Dominik Fleischmann

All Publications

• Denoising Multiphase Functional Cardiac CT Angiography Using Deep Learning and Synthetic Data. Radiology. Artificial intelligence Sandfort, V., Willemink, M., Codari, M., Mastrodicasa, D., Fleischmann, D. 2024: e230153

  Abstract

  "Just Accepted" papers have undergone full peer review and have been accepted for publication in Radiology: Artificial Intelligence. This article will undergo copyediting, layout, and proof review before it is published in its final version. Please note that during production of the final copyedited article, errors may be discovered which could affect the content. Coronary CT angiography (CTA) is increasingly used for cardiac diagnosis. Dose modulation techniques can reduce radiation dose, but resulting functional images are noisy and challenging for functional analysis. This retrospective study describes and evaluates a deep learning method for denoising functional cardiac imaging, taking advantage of multiphase information in a 3D convolutional neural network. Coronary CT angiograms (n = 566) were used to derive synthetic data for training. Deep learning-based image denoising (DLID) was compared with unprocessed images and a standard noise reduction algorithm (BM3D). Noise and signal-to-noise ratio measurements, as well as expert evaluation of image quality were performed. To validate the use of the denoised images for cardiac quantification, threshold-based segmentation was performed, and results were compared with manual measurements on unprocessed images. Deep learning-based denoised images showed significantly improved noise compared with standard denoising-based images (SD of left ventricular blood pool, 20.3 ± 42.5 HU versus 33.4 ± 39.8 HU for DLID versus BM3D, P < .0001). Expert evaluations of image quality were significantly higher in deep learningbased denoised images compared with standard denoising. Semiautomatic left ventricular size measurements on deep learning-based denoised images showed excellent correlation with expert quantification on unprocessed images (intraclass correlation coefficient, 0.97). Deep learning-based denoising using a 3D approach resulted in excellent denoising performance and facilitated valid automatic processing of cardiac functional imaging. ©RSNA, 2024.

  View details for DOI 10.1148/ryai.230153

  View details for PubMedID 38416035

• Hemodynamic effects of entry and exit tear size in aortic dissection evaluated with in vitro magnetic resonance imaging and fluid-structure interaction simulation. Scientific reports Zimmermann, J., Bäumler, K., Loecher, M., Cork, T. E., Marsden, A. L., Ennis, D. B., Fleischmann, D. 2023; 13 (1): 22557

  Abstract

  Understanding the complex interplay between morphologic and hemodynamic features in aortic dissection is critical for risk stratification and for the development of individualized therapy. This work evaluates the effects of entry and exit tear size on the hemodynamics in type B aortic dissection by comparing fluid-structure interaction (FSI) simulations with in vitro 4D-flow magnetic resonance imaging (MRI). A baseline patient-specific 3D-printed model and two variants with modified tear size (smaller entry tear, smaller exit tear) were embedded into a flow- and pressure-controlled setup to perform MRI as well as 12-point catheter-based pressure measurements. The same models defined the wall and fluid domains for FSI simulations, for which boundary conditions were matched with measured data. Results showed exceptionally well matched complex flow patterns between 4D-flow MRI and FSI simulations. Compared to the baseline model, false lumen flow volume decreased with either a smaller entry tear (- 17.8 and - 18.5%, for FSI simulation and 4D-flow MRI, respectively) or smaller exit tear (- 16.0 and - 17.3%). True to false lumen pressure difference (initially 11.0 and 7.9 mmHg, for FSI simulation and catheter-based pressure measurements, respectively) increased with a smaller entry tear (28.9 and 14.6 mmHg), and became negative with a smaller exit tear (- 20.6 and - 13.2 mmHg). This work establishes quantitative and qualitative effects of entry or exit tear size on hemodynamics in aortic dissection, with particularly notable impact observed on FL pressurization. FSI simulations demonstrate acceptable qualitative and quantitative agreement with flow imaging, supporting its deployment in clinical studies.

  View details for DOI 10.1038/s41598-023-49942-0

  View details for PubMedID 38110526

  View details for PubMedCentralID PMC10728172

• Registry of Aortic Diseases to Model Adverse Events and Progression (ROADMAP) in Uncomplicated Type B Aortic Dissection: Study Design and Rationale. Radiology. Cardiothoracic imaging Mastrodicasa, D., Willemink, M. J., Turner, V. L., Hinostroza, V., Codari, M., Hanneman, K., Ouzounian, M., Ocazionez Trujillo, D., Afifi, R. O., Hedgire, S., Burris, N. S., Yang, B., Lacomis, J. M., Gleason, T. G., Pacini, D., Folesani, G., Lovato, L., Hinzpeter, R., Alkadhi, H., Stillman, A. E., Chen, E. P., van Kuijk, S. M., Schurink, G. W., Sailer, A. M., Bäumler, K., Miller, D. C., Fischbein, M. P., Fleischmann, D. 2022; 4 (6): e220039

  Abstract

  To describe the design and methodological approach of a multicenter, retrospective study to externally validate a clinical and imaging-based model for predicting the risk of late adverse events in patients with initially uncomplicated type B aortic dissection (uTBAD).The Registry of Aortic Diseases to Model Adverse Events and Progression (ROADMAP) is a collaboration between 10 academic aortic centers in North America and Europe. Two centers have previously developed and internally validated a recently developed risk prediction model. Clinical and imaging data from eight ROADMAP centers will be used for external validation. Patients with uTBAD who survived the initial hospitalization between January 1, 2001, and December 31, 2013, with follow-up until 2020, will be retrospectively identified. Clinical and imaging data from the index hospitalization and all follow-up encounters will be collected at each center and transferred to the coordinating center for analysis. Baseline and follow-up CT scans will be evaluated by cardiovascular imaging experts using a standardized technique.The primary end point is the occurrence of late adverse events, defined as aneurysm formation (≥6 cm), rapid expansion of the aorta (≥1 cm/y), fatal or nonfatal aortic rupture, new refractory pain, uncontrollable hypertension, and organ or limb malperfusion. The previously derived multivariable model will be externally validated by using Cox proportional hazards regression modeling.This study will show whether a recent clinical and imaging-based risk prediction model for patients with uTBAD can be generalized to a larger population, which is an important step toward individualized risk stratification and therapy.Keywords: CT Angiography, Vascular, Aorta, Dissection, Outcomes Analysis, Aortic Dissection, MRI, TEVAR© RSNA, 2022See also the commentary by Rajiah in this issue.

  View details for DOI 10.1148/ryct.220039

  View details for PubMedID 36601455

  View details for PubMedCentralID PMC9806732

• Imaging and Surveillance of Chronic Aortic Dissection: A Scientific Statement From the American Heart Association. Circulation. Cardiovascular imaging Fleischmann, D., Afifi, R. O., Casanegra, A. I., Elefteriades, J. A., Gleason, T. G., Hanneman, K., Roselli, E. E., Willemink, M. J., Fischbein, M. P. 2022; 15 (3): e000075

  Abstract

  All patients surviving an acute aortic dissection require continued lifelong surveillance of their diseased aorta. Late complications, driven predominantly by chronic false lumen degeneration and aneurysm formation, often require surgical, endovascular, or hybrid interventions to treat or prevent aortic rupture. Imaging plays a central role in the medical decision-making of patients with chronic aortic dissection. Accurate aortic diameter measurements and rigorous, systematic documentation of diameter changes over time with different imaging equipment and modalities pose a range of practical challenges in these complex patients. Currently, no guidelines or recommendations for imaging surveillance in patients with chronic aortic dissection exist. In this document, we present state-of-the-art imaging and measurement techniques for patients with chronic aortic dissection and clarify the need for standardized measurements and reporting for lifelong surveillance. We also examine the emerging role of imaging and computer simulations to predict aortic false lumen degeneration, remodeling, and biomechanical failure from morphological and hemodynamic features. These insights may improve risk stratification, individualize contemporary treatment options, and potentially aid in the conception of novel treatment strategies in the future.

  View details for DOI 10.1161/HCI.0000000000000075

  View details for PubMedID 35172599

• Fluid-structure interaction simulations of patient-specific aortic dissection. Biomechanics and modeling in mechanobiology Baumler, K., Vedula, V., Sailer, A. M., Seo, J., Chiu, P., Mistelbauer, G., Chan, F. P., Fischbein, M. P., Marsden, A. L., Fleischmann, D. 2020

  Abstract

  Credible computational fluid dynamic (CFD) simulations of aortic dissection are challenging, because the defining parallel flow channels-the true and the false lumen-are separated from each other by a more or less mobile dissection membrane, which is made up of a delaminated portion of the elastic aortic wall. We present a comprehensive numerical framework for CFD simulations of aortic dissection, which captures the complex interplay between physiologic deformation, flow, pressures, and time-averaged wall shear stress (TAWSS) in a patient-specific model. Our numerical model includes (1) two-way fluid-structure interaction (FSI) to describe the dynamic deformation of the vessel wall and dissection flap; (2) prestress and (3) external tissue support of the structural domain to avoid unphysiologic dilation of the aortic wall and stretching of the dissection flap; (4) tethering of the aorta by intercostal and lumbar arteries to restrict translatory motion of the aorta; and a (5) independently defined elastic modulus for the dissection flap and the outer vessel wall to account for their different material properties. The patient-specific aortic geometry is derived from computed tomography angiography (CTA). Three-dimensional phase contrast magnetic resonance imaging (4D flow MRI) and the patient's blood pressure are used to inform physiologically realistic, patient-specific boundary conditions. Our simulations closely capture the cyclical deformation of the dissection membrane, with flow simulations in good agreement with 4D flow MRI. We demonstrate that decreasing flap stiffness from [Formula: see text] to [Formula: see text] kPa (a) increases the displacement of the dissection flap from 1.4 to 13.4 mm, (b) decreases the surface area of TAWSS by a factor of 2.3, (c) decreases the mean pressure difference between true lumen and false lumen by a factor of 0.63, and (d) decreases the true lumen flow rate by up to 20% in the abdominal aorta. We conclude that the mobility of the dissection flap substantially influences local hemodynamics and therefore needs to be accounted for in patient-specific simulations of aortic dissection. Further research to accurately measure flap stiffness and its local variations could help advance future CFD applications.

  View details for DOI 10.1007/s10237-020-01294-8

  View details for PubMedID 31993829

• Aortic growth and development of partial false lumen thrombosis are associated with late adverse events in type B aortic dissection. The Journal of thoracic and cardiovascular surgery Higashigaito, K. n., Sailer, A. M., van Kuijk, S. M., Willemink, M. J., Hahn, L. D., Hastie, T. J., Miller, D. C., Fischbein, M. P., Fleischmann, D. n. 2019

  Abstract

  Patients with medically treated type B aortic dissection (TBAD) remain at significant risk for late adverse events (LAEs). We hypothesize that not only initial morphological features, but also their change over time at follow-up are associated with LAEs.Baseline and 188 follow-up computed tomography (CT) scans with a median follow-up time of 4 years (range, 10 days to 12.7 years) of 47 patients with acute uncomplicated TBAD were retrospectively reviewed. Morphological features (n = 8) were quantified at baseline and each follow-up. Medical records were reviewed for LAEs, which were defined according to current guidelines. To assess the effects of changes of morphological features over time, the linear mixed effects models were combined with Cox proportional hazards regression for the time-to-event outcome using a joint modeling approach.LAEs occurred in 21 of 47 patients at a median of 6.6 years (95% confidence interval [CI], 5.1-11.2 years). Among the 8 investigated morphological features, the following 3 features showed strong association with LAEs: increase in partial false lumen thrombosis area (hazard ratio [HR], 1.39; 95% CI, 1.18-1.66 per cm2 increase; P < .001), increase of major aortic diameter (HR, 1.24; 95% CI, 1.13-1.37 per mm increase; P < .001), and increase in the circumferential extent of false lumen (HR, 1.05; 95% CI, 1.01-1.10 per degree increase; P < .001).In medically treated TBAD, increases in aortic diameter, new or increased partial false lumen thrombosis area, and increases of circumferential extent of the false lumen are strongly associated with LAEs.

  View details for DOI 10.1016/j.jtcvs.2019.10.074

  View details for PubMedID 31839226

• Acute Limited Intimal Tears of the Thoracic Aorta. Journal of the American College of Cardiology Chin, A. S., Willemink, M. J., Kino, A. n., Hinostroza, V. n., Sailer, A. M., Fischbein, M. P., Mitchell, R. S., Berry, G. J., Miller, D. C., Fleischmann, D. n. 2018; 71 (24): 2773–85

  Abstract

  Limited intimal tears (LITs) of the aorta (Class 3 dissection variant) are the least common form of aortic pathology in patients presenting with acute aortic syndrome (AAS). LITs are difficult to detect on imaging and may be underappreciated.This study sought to describe the frequency, pathology, treatment, and outcome of LITs compared with other AAS, and to demonstrate that LITs can be detected pre-operatively by contemporary imaging.The authors retrospectively reviewed 497 patients admitted for 513 AAS events at a single academic aortic center between 2003 and 2012. AAS were classified into classic dissection (AD), intramural hematoma, LIT, penetrating atherosclerotic ulcer, and rupturing thoracic aortic aneurysm. The prevalence, pertinent risk factors, and detailed imaging findings with surgical and pathological correlation of LITs are described. Management, early outcomes, and late mortality are reported.Among 497 patients with AAS, the authors identified 24 LITs (4.8% of AAS) in 16 men and 8 women (17 type A, 7 type B). Patients with LITs were older than those with AD, and type A LITs had similarly dilated ascending aortas as type A AD. Three patients presented with rupture. Eleven patients underwent urgent surgical aortic replacement, and 2 patients underwent endovascular repair. Medial degeneration was present in all surgical specimens. In-hospital mortality was 4% (1 of 24), and in total, 5 patients with LIT died subsequently at 1.5 years (interquartile range [IQR]: 0.3 to 2.5 years). Computed tomography imaging detected all but 1 LIT, best visualized on volume-rendered images.LITs are rare acute aortic lesions within the dissection spectrum, with similar presentation, complications, and outcomes compared with AD and intramural hematoma. Awareness of this lesion allows pre-operative diagnosis using high-quality computed tomography angiography.

  View details for PubMedID 29903350

• Computed Tomography Imaging Features in Acute Uncomplicated Stanford Type-B Aortic Dissection Predict Late Adverse Events CIRCULATION-CARDIOVASCULAR IMAGING Sailer, A. M., Van Kuijk, S. M., Nelemans, P. J., Chin, A. S., Kino, A., Huininga, M., Schmidt, J., Mistelbauer, G., Baeumler, K., Chiu, P., Fischbein, M. P., Dake, M. D., Miller, D. C., Schurink, G. W., Fleischmann, D. 2017; 10 (4)

  Abstract

  Medical treatment of initially uncomplicated acute Stanford type-B aortic dissection is associated with a high rate of late adverse events. Identification of individuals who potentially benefit from preventive endografting is highly desirable.The association of computed tomography imaging features with late adverse events was retrospectively assessed in 83 patients with acute uncomplicated Stanford type-B aortic dissection, followed over a median of 850 (interquartile range 247-1824) days. Adverse events were defined as fatal or nonfatal aortic rupture, rapid aortic growth (>10 mm/y), aneurysm formation (≥6 cm), organ or limb ischemia, or new uncontrollable hypertension or pain. Five significant predictors were identified using multivariable Cox regression analysis: connective tissue disease (hazard ratio [HR] 2.94, 95% confidence interval [CI]: 1.29-6.72; P=0.01), circumferential extent of false lumen in angular degrees (HR 1.03 per degree, 95% CI: 1.01-1.04, P=0.003), maximum aortic diameter (HR 1.10 per mm, 95% CI: 1.02-1.18, P=0.015), false lumen outflow (HR 0.999 per mL/min, 95% CI: 0.998-1.000; P=0.055), and number of intercostal arteries (HR 0.89 per n, 95% CI: 0.80-0.98; P=0.024). A prediction model was constructed to calculate patient specific risk at 1, 2, and 5 years and to stratify patients into high-, intermediate-, and low-risk groups. The model was internally validated by bootstrapping and showed good discriminatory ability with an optimism-corrected C statistic of 70.1%.Computed tomography imaging-based morphological features combined into a prediction model may be able to identify patients at high risk for late adverse events after an initially uncomplicated type-B aortic dissection.

  View details for DOI 10.1161/CIRCIMAGING.116.005709

  View details for PubMedID 28360261

• Prognostic significance of early aortic remodeling in acute uncomplicated type B aortic dissection and intramural hematoma. The Journal of thoracic and cardiovascular surgery Sailer, A. M., Nelemans, P. J., Hastie, T. J., Chin, A. S., Huininga, M. n., Chiu, P. n., Fischbein, M. P., Dake, M. D., Miller, D. C., Schurink, G. W., Fleischmann, D. n. 2017; 154 (4): 1192–1200

  Abstract

  Patients with Stanford type B aortic dissections (ADs) are at risk of long-term disease progression and late complications. The aim of this study was to evaluate the natural course and evolution of acute type B AD and intramural hematomas (IMHs) in patients who presented without complications during their initial hospital admission and who were treated with optimal medical management (MM).Databases from 2 aortic centers in Europe and the United States were used to identify 136 patients with acute type B AD (n = 92) and acute type B IMH (n = 44) who presented without complications during their index admission and were treated with MM. Computed tomography angiography scans were available at onset (≤14 days) and during follow-up for those patients. Relevant data, including evidence of adverse events during follow-up (AE; defined according to current guidelines), were retrieved from medical records and by reviewing computed tomography scan images. Aortic diameters were measured with dedicated 3-dimensional software.The 1-, 2-, and 5-year event-free survival rates of patients with type B AD were 84.3% (95% confidence interval [CI], 74.4-90.6), 75.4% (95% CI, 64.0-83.7), and 62.6% (95% CI, 68.9-73.6), respectively. Corresponding estimates for IMH were 76.5% (95% CI, 57.8-87.8), 76.5% (95% CI, 57.8-87.8), and 68.9% (95% CI, 45.2-83.9), respectively. In patients with type B AD, risk of an AE increased with aortic growth within the first 6 months after onset. A diameter increase of 5 mm in the first half year was associated with a relative risk for AE of 2.29 (95% CI, 1.70-3.09) compared with the median 6 months' growth of 2.4 mm. In approximately 60% of patients with IMH, the abnormality resolved within 12 months and in the patients with nonresolving IMH, risk of an adverse event was greatest in the first year after onset and remained stable thereafter.More than one third of patients with initially uncomplicated type B AD suffer an AE under MM within 5 years of initial diagnosis. In patients with nonresolving IMH, most adverse events are observed in the first year after onset. In patients with type B AD an early aortic growth is associated with a greater risk of AE.

  View details for PubMedID 28668458

• Evaluation of Two Iterative Techniques for Reducing Metal Artifacts in Computed Tomography RADIOLOGY Boas, F. E., Fleischmann, D. 2011; 259 (3): 894-902

  Abstract

  To evaluate two methods for reducing metal artifacts in computed tomography (CT)--the metal deletion technique (MDT) and the selective algebraic reconstruction technique (SART)--and compare these methods with filtered back projection (FBP) and linear interpolation (LI).The institutional review board approved this retrospective HIPAA-compliant study; informed patient consent was waived. Simulated projection data were calculated for a phantom that contained water, soft tissue, bone, and iron. Clinical projection data were obtained retrospectively from 11 consecutively identified CT scans with metal streak artifacts, with a total of 178 sections containing metal. Each scan was reconstructed using FBP, LI, SART, and MDT. The simulated scans were evaluated quantitatively by calculating the average error in Hounsfield units for each pixel compared with the original phantom. Two radiologists who were blinded to the reconstruction algorithms used qualitatively evaluated the clinical scans, ranking the overall severity of artifacts for each algorithm. P values for comparisons of the image quality ranks were calculated from the binomial distribution.The simulations showed that MDT reduces artifacts due to photon starvation, beam hardening, and motion and does not introduce new streaks between metal and bone. MDT had the lowest average error (76% less than FBP, 42% less than LI, 17% less than SART). Blinded comparison of the clinical scans revealed that MDT had the best image quality 100% of the time (95% confidence interval: 72%, 100%). LI had the second best image quality, and SART and FBP had the worst image quality. On images from two CT scans, as compared with images generated by the scanner, MDT revealed information of potential clinical importance.For a wide range of scans, MDT yields reduced metal streak artifacts and better-quality images than does FBP, LI, or SART.http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101782/-/DC1.

  View details for DOI 10.1148/radiol.11101782

  View details for Web of Science ID 000290898100030

  View details for PubMedID 21357521

• Computed tomography-old ideas and new technology EUROPEAN RADIOLOGY Fleischmann, D., Boas, F. E. 2011; 21 (3): 510-517

  Abstract

  Several recently introduced 'new' techniques in computed tomography--iterative reconstruction, gated cardiac CT, multiple-source, and dual-energy CT--actually date back to the early days of CT. We review the historic origins and evolution of these techniques, which may provide some insight into the latest innovations in commercial CT systems.

  View details for DOI 10.1007/s00330-011-2056-z

  View details for Web of Science ID 000286943600013

  View details for PubMedID 21249371

• Dual-energy CT Discrimination of Iodine and Calcium: Experimental Results and Implications for Lower Extremity CT Angiography ACADEMIC RADIOLOGY Tran, D. N., Straka, M., Roos, J. E., Napel, S., Fleischmann, D. 2009; 16 (2): 160-171

  Abstract

  The purpose of this work was to measure the accuracy of dual-energy computed tomography for identifying iodine and calcium and to determine the effects of calcium suppression in phantoms and lower-extremity computed tomographic (CT) angiographic data sets.Using a three-material basis decomposition method for 80- and 140-kVp data, the accuracy of correctly identified contrast medium and calcium voxels and the mean attenuation before and after calcium suppression were computed. Experiments were first performed on a phantom of homogenous contrast medium and hydroxyapatite samples with mean attenuation of 57.2, 126, and 274 Hounsfield units (HU) and 50.0, 122, and 265 HU, respectively. Experiments were repeated in corresponding attenuation groups of voxels from manually segmented bones and contrast medium-enhanced arteries in a lower-extremity CT angiographic data set with mean attenuation of 293 and 434 HU, respectively. Calcium suppression in atherosclerotic plaques of a cadaveric specimen was also studied, using micro-computed tomography as a reference, and in a lower-extremity CT angiographic data set with substantial below-knee calcified plaques.Higher concentrations showed increased accuracy of iodine and hydroxyapatite identification of 87.4%, 99.7%, and 99.9% and 88.0%, 95.0%, and 99.9%, respectively. Calcium suppression was also more accurate with higher concentrations of iodine and hydroxyapatite, with mean attenuation after suppression of 47.1, 122, and 263 HU and 7.14, 11.6, and 12.6 HU, respectively. Similar patterns were seen in the corresponding attenuation groups of the contrast medium-enhanced arteries and bone in the clinical data set, which had overall accuracy of 81.3% and 78.9%, respectively, and mean attenuation after calcium suppression of 254 and 73.7 HU, respectively. The suppression of calcified atherosclerotic plaque was accurate compared with the micro-CT reference; however, the suppression in the clinical data set showed probable inappropriate suppression of the small vessels.Dual-energy computed tomography can detect and differentiate between contrast medium and calcified tissues, but its accuracy is dependent on the CT density of tissues and limited when CT attenuation is low.

  View details for DOI 10.1016/j.acra.2008.09.004

  View details for Web of Science ID 000262536500007

  View details for PubMedID 19124101

• An improved algorithm for femoropopliteal artery centerline restoration using prior knowledge of shapes and image space data MEDICAL PHYSICS Rakshe, T., Fleischmann, D., Rosenberg, J., Roos, J. E., Straka, M., Napel, S. 2008; 35 (7): 3372-3382

  Abstract

  Accurate arterial centerline extraction is essential for comprehensive visualization in CT Angiography. Time consuming manual tracking is needed when automated methods fail to track centerlines through severely diseased and occluded vessels. A previously described algorithm, Partial Vector Space Projection (PVSP), which uses vessel shape information from a database to bridge occlusions of the femoropopliteal artery, has a limited accuracy in long (>100 mm) occlusions. In this article we introduce a new algorithm, Intermediate Point Detection (IPD), which uses calcifications in the occluded artery to provide additional information about the location of the centerline to facilitate improvement in PVSP performance. It identifies calcified plaque in image space to find the most useful point within the occlusion to improve the estimate from PVSP. In this algorithm candidates for calcified plaque are automatically identified on axial CT slices in a restricted region around the estimate obtained from PVSP. A modified Canny edge detector identifies the edge of the calcified plaque and a convex polygon fit is used to find the edge of the calcification bordering the wall of the vessel. The Hough transform for circles estimates the center of the vessel on the slice, which serves as a candidate intermediate point. Each candidate is characterized by two scores based on radius and relative position within the occluded segment, and a polynomial function is constructed to define a net score representing the potential benefit of using this candidate for improving the centerline. We tested our approach in 44 femoropopliteal artery occlusions of lengths up to 398 mm in 30 patients with peripheral arterial occlusive disease. Centerlines were tracked manually by four-experts, twice each, with their mean serving as the reference standard. All occlusions were first interpolated with PVSP using a database of femoropopliteal arterial shapes obtained from a total of 60 subjects. Occlusions longer than 80 mm (N = 20) were then processed with the IPD algorithm, provided calcifications were found (N = 14). We used the maximum point-wise distance of an interpolated curve from the reference standard as our error metric. The IPD algorithm significantly reduced the average error of the initial PVSP from 2.76 to 1.86 mm (p < 0.01). The error was less than the clinically desirable 3 mm (smallest radius of the femoropopliteal artery) in 13 of 14 occlusions. The IPD algorithm achieved results within the range of the human readers in 11 of 14 cases. We conclude that the additional use of sparse but specific image space information, such as calcified atherosclerotic plaque, can be used to substantially improve the performance of a previously described knowledge-based method to restore the centerlines of femoropopliteal arterial occlusions.

  View details for DOI 10.1118/1.2940194

  View details for Web of Science ID 000257231700039

  View details for PubMedID 18697561

  View details for PubMedCentralID PMC2673553

• Femoropopliteal artery centerline interpolation using contralateral shape MEDICAL PHYSICS Tran, D. N., Fleischmann, D., Rakshe, T., Roos, J. E., Rosenberg, J., Straka, M., Napel, S. 2007; 34 (9): 3428-3435

  Abstract

  Curved planar reformation allows comprehensive visualization of arterial flow channels, providing information about calcified and noncalcified plaques and degrees of stenoses. Existing semiautomated centerline-extraction algorithms for curved planar reformation generation fail in severely diseased and occluded arteries. We explored whether contralateral shape information could be used to reconstruct centerlines through femoropopliteal occlusions. We obtained CT angiography data sets of 29 subjects (16m/13f, 19-86yo) without peripheral arterial occlusive disease and five consecutive subjects (1m/4f, 54-85yo) with unilateral femoropopliteal arterial occlusions. A gradient-based method was used to extract the femoropopliteal centerlines in nondiseased segments. Centerlines of the five occluded segments were manually determined by four experts, two times each. We interpolated missing centerlines in 2475 simulated occlusions of various occlusion lengths in nondiseased subjects. We used different curve registration methods (reflection, similarity, affine, and global polynomial) to align the nonoccluded segments, matched the end points of the occluded segments to the corresponding patent end points, and recorded maximum Euclidean distances to the known centerlines. We also compared our algorithm to an existing knowledge-based PCA interpolation algorithm using the nondiseased subjects. In the five subjects with real femoropopliteal occlusions, we measured the maximum Euclidean distance and the percentage of the interpolation that remained within a typical 3 mm radius vessel. In the nondiseased subjects, we found that the rigid registration methods were not significantly (p<0.750) different among themselves but were more accurate than the nonrigid methods (p<0.001). In simulations using nondiseased subjects, our method produced centerlines that stayed within 3 mm of a semiautomatically tracked centerline in occlusions up to 100 mm in length; however, the PCA method was significantly more accurate for all occlusions lengths. In the actual clinical cases, we found the following [occlusion length (mm):error (mm)]: 16.5:0.775, 42.0:1.54, 79.9:1.82, 145:3.23, and 292:6.13, which were almost always more accurate than the PCA algorithm. We conclude that the use of contralateral shape information, when available, is a promising method for the interpolation of centerlines through arterial occlusions.

  View details for DOI 10.1118/1.2759603

  View details for Web of Science ID 000249547200003

  View details for PubMedID 17926944

• Multipath curved planar reformation of the peripheral arterial tree in CT angiography RADIOLOGY Roos, J. E., Fleischmann, D., Koechl, A., Rakshe, T., Straka, M., Napoli, A., Kanitsar, A., Sramek, M., Groeller, E. 2007; 244 (1): 281-290

  Abstract

  The study was approved by the institutional review board, and informed consent was obtained. The purpose of the study was to prospectively quantify the angular visibility range, determine the existence of orthogonal viewing pairs, and characterize the conditions that cause artifacts in multipath curved planar reformations (MPCPRs) of the peripheral arterial tree in 10 patients (eight men and two women; mean age, 69 years; range, 54-80 years) with peripheral arterial occlusive disease. Percentage of segments with the maximal possible visibility score of 1 was significantly greater (odds ratio, 1.42; P<.001) for MPCPRs than for maximum intensity projections. One or more orthogonal viewing pairs were identified for all above-knee arterial segments, and artifactual vessel distortion was observed when the vessel axis approached a horizontal course in MPCPRs.

  View details for DOI 10.1148/radiol.2441060976

  View details for Web of Science ID 000247436500032

  View details for PubMedID 17495179

• Knowledge-based interpolation of curves: Application to femoropopliteal arterial centerline restoration MEDICAL IMAGE ANALYSIS Rakshe, T., Fleischmann, D., Rosenberg, J., Roos, J. E., Napel, S. 2007; 11 (2): 157-168

  Abstract

  We present a novel algorithm, Partial Vector Space Projection (PVSP), for estimation of missing data given a database of similar datasets, and demonstrate its use in restoring the centerlines through simulated occlusions of femoropopliteal arteries, derived from CT angiography data. The algorithm performs Principal Component Analysis (PCA) on a database of centerlines to obtain a set of orthonormal basis functions defined in a scaled and oriented frame of reference, and assumes that any curve not in the database can be represented as a linear combination of these basis functions. Using a database of centerlines derived from 30 normal femoropopliteal arteries, we evaluated the algorithm, and compared it to a correlation-based linear Minimum Mean Squared Error (MMSE) method, by deleting portions of a centerline for several occlusion lengths (OL: 10 mm, 25 mm, 50 mm, 75 mm, 100 mm, 125 mm, 150 mm, 175 mm and 200 mm). For each simulated occlusion, we projected the partially known dataset on the set of basis functions derived from the remaining 29 curves to restore the missing segment. We calculated the maximum point-wise distance (Maximum Departure or MD) between the actual and estimated centerline as the error metric. Mean (standard deviation) of MD increased from 0.18 (0.14) to 4.35 (2.23) as OL increased. The results were fairly accurate even for large occlusion lengths and are clinically useful. The results were consistently better than those using the MMSE method. Multivariate regression analysis found that OL and the root-mean-square error in the 2 cm proximal and distal to the occlusion accounted for most of the error.

  View details for DOI 10.1016/j.media.2006.11.005

  View details for Web of Science ID 000245596200005

  View details for PubMedID 17218147

  View details for PubMedCentralID PMC1989127

• Quantification of intravenously administered contrast medium transit through the peripheral arteries: Implications for CT angiography RADIOLOGY Fleischmann, D., Rubin, G. D. 2005; 236 (3): 1076-1082

  Abstract

  To prospectively determine the range of aortopopliteal bolus transit times in patients with moderate-to-severe peripheral arterial occlusive disease (PAOD) as a guideline for developing injection strategies for computed tomographic (CT) angiography of peripheral arteries.The study protocol was approved by the local ethics board, and informed consent was obtained. Twenty patients with PAOD referred for CT angiography of the lower extremities were categorized into two groups, Fontaine stage IIb (group 1) and stage III or IV (group 2), and demographic information was collected. In all patients, a 16-mL test bolus was injected intravenously, and single-level dynamic acquisitions were obtained at the level of the abdominal aorta. After injection of a second 16-mL test bolus, dynamic acquisitions were obtained at the level of the knee (popliteal arteries). Aortopopliteal bolus transit times were calculated by subtracting the time to peak enhancement in the popliteal arteries from that in the aorta. Aortopopliteal transit speeds also were derived. Transit times and speeds were compared graphically between clinical stage groups. The time required for the contrast medium to enhance the entire peripheral arterial tree in patients with PAOD was estimated by using linear extrapolation.Sixteen men and four women with a mean age of 69 years (range, 49-86 years) were included. Twelve patients were included in group 1, and eight patients, in group 2. Aortopopliteal bolus transit times ranged from 4 to 24 seconds (median, 8 seconds) in all subjects, which corresponded to bolus transit speeds of 177 and 29 mm/sec, respectively. Wide overlap of transit times and transit speeds was observed between clinical stage groups. The estimated time needed for the bolus to enhance the entire peripheral arterial tree was 6-39 seconds.Aortopopliteal bolus transit times differ widely among patients and may be substantially delayed in all patients with PAOD. Empirical injection protocols should include an injection duration of 35 seconds or more, as well as an increased scanning delay, with table speeds of more than 30 mm/sec.

  View details for DOI 10.1148/radiol.2363041392

  View details for Web of Science ID 000231412600046

  View details for PubMedID 16000649

• Non-Linear Model Fitting to Parameterize Diseased Blood Vessels IEEE Vizualization 2004 La Cruz A, Straka M, Köchl A, Srámek M, Gröller E, Fleischmann D 2004: 393-400
• VesselGlyph: Focus & Context Visualization in CT-Angiography IEEE Visualization 2004 Straka M, Cervenanský M, La Cruz A, Köchl A, Srámek M, Gröller E, Fleischmann D 2004: 385-392
• CPR - Curved Planar Reformation IEEE Visualization 2002 Kanitsar A, Fleischmann D, Wegenkittl R, Felkel P, Gröller E 2002: 37-44
• Accuracy of predicting and controlling time-dependent aortic enhancement from a test bolus injection JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Hittmair, K., Fleischmann, D. 2001; 25 (2): 287-294

  Abstract

  The purpose of this work was to determine the accuracy of predicting arterial enhancement from peripheral versus central venous test bolus injections at CT angiography (CTA).In 40 patients with abdominal aortic aneurysms, aortoiliac enhancement profiles were predicted by mathematical deconvolution of the time-attenuation response to a 16 ml test bolus injection. Injection sites were either a cubital vein (n = 20) or a central venous injection site (n = 20). The accuracy of predicting enhancement was quantified as the "off-predicted deviation" (calculated as mean squared differences between observed minus predicted enhancement values) in all patients.Off-predicted deviation was significantly smaller in the central venous injection group (17 +/- 6 HU) than the peripheral injection group (33 +/- 18 HU) (p < 0.001).Arterial enhancement at CTA can be mathematically predicted and controlled more accurately if a central venous injection site is used. Automated saline flushing of the veins might improve the accuracy of the mathematical model for peripheral injections.

  View details for Web of Science ID 000167521000024

  View details for PubMedID 11242230

• Quantitative determination of age-related geometric changes in the normal abdominal aorta JOURNAL OF VASCULAR SURGERY Fleischmann, D., Hastie, T. J., Dannegger, F. C., Paik, D. S., Tillich, M., Zarins, C. K., Rubin, G. D. 2001; 33 (1): 97-105

  Abstract

  We conducted a novel quantitative three-dimensional analysis of computed tomography (CT) angiograms to establish the relationship between aortic geometry and age, sex, and body surface area in healthy subjects.Abdominal helical CT angiograms from 77 healthy potential renal donors (33 men/44 women; mean age, 44 years; age range, 19-67 years) were selected. In each dataset, orthonormal cross-sectional area and diameter measurements were obtained at 1-mm intervals along the automatically calculated central axis of the abdominal aorta. The aorta was subdivided into six consecutive anatomic segments (supraceliac, supramesenteric, suprarenal, inter-renal, proximal infrarenal, and distal infrarenal). The interrelated effects of anatomic segment, age, sex, and body surface area on cross-sectional dimensions were analyzed with linear mixed-effects and varying-coefficient statistical models.We found that significant effects of sex and of body surface area on aortic diameters were similar at all anatomic levels. The effect of age, however, was interrelated with anatomic position, and gradually decreasing slopes of significant diameter-versus-age relationships along the aorta, which ranged from 0.14 mm/y (P <.0001) proximally to 0.03 mm/y (P =.013) distally in the abdominal aorta, were shown.The abdominal aorta undergoes considerable geometric changes when a patient is between 19 and 67 years of age, leading to an increase of aortic taper with time. The hemodynamic consequences of this geometric evolution for the development of aortic disease still need to be established.

  View details for Web of Science ID 000166576900022

  View details for PubMedID 11137929

• Improved uniformity of aortic enhancement with customized contrast medium injection protocols at CT angiography RADIOLOGY Fleischmann, D., Rubin, G. D., Bankier, A. A., Hittmair, K. 2000; 214 (2): 363-371

  Abstract

  To compare the uniformity of aortoiliac opacification obtained from uniphasic contrast medium injections versus individualized biphasic injections at computed tomographic (CT) angiography.Thirty-two patients with an abdominal aortic aneurysm underwent CT angiography. In 16 patients (group 1), 120 mL of contrast material was administered at a flow rate of 4 mL/sec. In the other 16 patients (group 2), biphasic injection protocols were computed by using mathematic deconvolution of each patient's time-attenuation response to a standardized test injection. Attenuation uniformity was quantified as the "plateau deviation" of enhancement values, which were calculated as the SD of the time-contiguous attenuation values observed during the 30-second scanning period.Group 2 patients received between 77 and 165 mL (mean, 115 mL) of contrast medium. Initial flow rates ranged from 4.1 to 10.0 mL/sec (mean, 6.8 mL/sec) for the first 4-6 seconds; continuing flow rates ranged from 2.0 to 4.8 mL/sec (mean, 3.1 mL/sec) for the remaining 24-26 seconds. The plateau deviation was significantly smaller in group 2 patients (19 HU) versus group 1 patients (38 HU, P <.001).At CT angiography, tailored biphasic injections led to more uniform aortoiliac enhancement, compared with standard uniphasic injections of contrast medium.

  View details for Web of Science ID 000085023400009

  View details for PubMedID 10671582

• Mathematical analysis of arterial enhancement and optimization of bolus geometry for CT angiography using the discrete Fourier transform JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Fleischmann, D., Hittmair, K. 1999; 23 (3): 474-484

  Abstract

  The goal of this work was to develop a clinically applicable mathematical algorithm to analyze and optimize individual arterial enhancement in CT angiography (CTA).Assuming a time-invariant linear system, the discrete Fourier transform was used to calculate the transfer function of the system ("patient function") from the arterial time-attenuation response to a test bolus. The patient function was subsequently used to predict aortic enhancement in five select patients and to calculate optimized biphasic injection protocols in two of these patients undergoing CTA of the abdominal aorta.Arterial time-attenuation curves were accurately predicted in all patients. Optimized biphasic contrast agent injection protocols resulted in uniform aortic enhancement at the predefined level over the entire scanning period in both subjects despite markedly different contrast agent volumes and injection rates used.Fourier analysis of the time-attenuation response to a test bolus is a simple and feasible approach to optimize arterial enhancement in CTA.

  View details for Web of Science ID 000080366000026

  View details for PubMedID 10348458

• Three-dimensional spiral CT cholangiography in patients with suspected obstructive biliary disease: Comparison with endoscopic retrograde cholangiography 80th RSNA Scientific Assembly Fleischmann, D., Ringl, H., Schofl, R., Potzi, R., Kontrus, M., Henk, C., Bankier, A. A., Kettenbach, J., Mostbeck, G. H. RADIOLOGICAL SOC NORTH AMERICA. 1996: 861–68

  Abstract

  To evaluate the diagnostic potential of spiral computed tomography (CT) performed after the administration of cholangiographic contrast material (spiral CT cholangiography) in patients with suspected obstructive biliary disease.After infusion of meglumine iodoxamate, 29 patients underwent upper abdominal spiral CT with subsequent three-dimensional rendering of the biliary tract. In 27 patients, the presence, site, and extent of biliary obstruction were compared with that at endoscopic retrograde cholangiography (ERC).Spiral CT cholangiography correctly depicted biliary obstruction in 14 of 27 patients, with no false-positive or false-negative cases. In one patient, the precise length of a common bile duct stenosis could not be assessed with spiral CT cholangiography. ERC demonstrated intrahepatic ductal stenoses more clearly in two patients. In two patients with hilar cholangiocarcinomas, spiral CT cholangiography depicted undrained areas not seen with ERC.Spiral CT cholangiography allows accurate assessment of the biliary system in patients with suspected obstructive biliary disease.

  View details for Web of Science ID A1996TW21200043

  View details for PubMedID 8628884

• Synthetic surface mesh generation of aortic dissections using statistical shape modeling COMPUTERS & GRAPHICS-UK Ostendorf, K., Baeumler, K., Mastrodicasa, D., Fleischmann, D., Preim, B., Mistelbauer, G. 2024; 124

  View details for DOI 10.1016/j.cag.2024.104070

  View details for Web of Science ID 001314772100001

• Advanced visualization of aortic dissection anatomy and hemodynamics COMPUTERS & GRAPHICS-UK Schroeder, A., Ostendorf, K., Baeumler, K., Mastrodicasa, D., Sandfort, V., Fleischmann, D., Preim, B., Mistelbauer, G. 2024; 124

  View details for DOI 10.1016/j.cag.2024.104060

  View details for Web of Science ID 001309002200001

• Early 3D Growth in Uncomplicated Type B Aortic Dissection is Associated with Long-Term Outcomes. Journal of vascular surgery Marway, P. S., Campello Jorge, C. A., Tjahjadi, N., Baker, T. J., Mistelbauer, G., Baeumler, K., Hinostroza, V., Higashigaito, K., Mastrodicasa, D., Masotti, M., Nordsletten, D., Patel, H. J., Fleischmann, D., Burris, N. S. 2024

  Abstract

  Late adverse events (LAE) are common among initially uncomplicated type B aortic dissection (uTBAD), however, identifying those patients at highest risk of LAE remains a significant challenge. Early false lumen (FL) growth has been suggested to increase risk, but confident determination of growth is often hampered by error in 2D clinical measurements. Semi-automated 3D mapping of aortic growth, such as by vascular deformation mapping (VDM), can potentially overcome this limitation using CT angiograms (CTA). We hypothesized that FL growth in the early pre-dissection phase by VDM can accurately predict LAEs.We performed a two-centre retrospective study of uTBAD patients, with paired CTAs in the acute (1-14 days) and subacute/early chronic (1-6 months) periods. VDM analysis was used to map 3D growth. Standard clinical CT measures (i.e., aortic diameters, tear characteristics) were also collected. Multivariate analysis was conducted using a decision tree and Cox proportional hazards model. LAEs were defined as aneurysmal FL (>55mm); rapid growth (>5mm within 6 months); aorta-specific mortality, rupture, or re-dissection.107 (69% male) initially uTBAD patients met inclusion criteria with a median follow-up of 7.3 (IQR 4.7-9.9) years. LAEs occurred in 72 patients (67%) at 2.5 (IQR 0.7-4.8) years after the initial event. A multivariate decision tree model identified VDM growth (>2.1 mm) and baseline diameter (>42.7 mm) as optimal predictors of LAEs (AUC-ROC = 0.94), achieving an 87% accuracy (sensitivity of 93%, specificity of 76%) after leave-one-out validation. Guideline reported high-risk features were not significantly different between groups.Early growth of the FL in uTBAD was the best tested indicator for LAEs and improves upon the current gold-standard of baseline diameter in selecting patients for early prophylactic TEVAR.

  View details for DOI 10.1016/j.jvs.2024.08.059

  View details for PubMedID 39222827

• Demographics, utilization, workflow and outcomes based on observational data from the RSNA-ACR 3D Printing Registry. Journal of the American College of Radiology : JACR Wang, K. C., Ryan, J. R., Chepelev, L., Wake, N., Quigley, E. P., Santiago, L., Wentworth, A., Alexander, A., Morris, J. M., Fleischmann, D., Ballard, D. H., Ravi, P., Hirsch, J. D., Sturgeon, G. M., Huang, Y. H., Decker, S. J., von Windheim, N., Pugliese, R. S., Hidalgo, R. V., Patel, P., Colon, J., Thieringer, F. M., Rybicki, F. J. 2024

  Abstract

  To report data from the first three years of operation of the RSNA-ACR 3D Printing Registry.Data from June 2020 to June 2023 was extracted, including demographics, indications, workflow and user assessments. Clinical indications were stratified by 12 organ systems. Imaging modalities, printing technologies and number of parts per case were assessed. Effort data was analyzed, dividing staff into provider and non-provider categories. The opinions of clinical users were evaluated through a Likert-scale questionnaire, and estimates of procedure time saved were collected.A total of 20 sites and 2,637 cases were included, consisting of 1,863 anatomic models and 774 anatomic guides. Mean patient age for models and guides was 42.4 ± 24.5 years and 56.3 ± 18.5 years respectively. Cardiac models were the most common type of models (27.2%), and neurologic guides were the most common type of guides (42.4%). Material jetting, vat photopolymerization and material extrusion were the most common printing technologies used overall (85.6% of all cases). On average, providers spent 92.4 minutes and non-providers spent 335.0 minutes per case. Providers spent most time on consultation (33.6 minutes), while non-providers focused most on segmentation (148.0 minutes). Confidence in treatment plans increased after using 3D printing (p<.001). Estimated procedure time savings for 155 cases was 40.5 ± 26.1 minutes.3D printing is performed in healthcare facilities for many clinical indications. The registry provides insight into the technologies and workflows used to create anatomic models and guides, and the data shows clinical benefits from 3D printing.

  View details for DOI 10.1016/j.jacr.2024.07.019

  View details for PubMedID 39117182

• Feasibility of virtual non-iodine coronary calcium scoring on dual source photon-counting coronary CT angiography: a dynamic phantom study. European radiology Dobrolinska, M. M., Koetzier, L. R., Greuter, M. J., Vliegenthart, R., van der Bie, J., Prakken, N. H., Slart, R. H., Leiner, T., Budde, R. P., Mastrodicasa, D., Booij, R., Fleischmann, D., Willemink, M. J., van Straten, M., van der Werf, N. R. 2024

  Abstract

  The aim of our current systematic dynamic phantom study was first, to optimize reconstruction parameters of coronary CTA (CCTA) acquired on photon counting CT (PCCT) for coronary artery calcium (CAC) scoring, and second, to assess the feasibility of calculating CAC scores from CCTA, in comparison to reference calcium scoring CT (CSCT) scans.In this phantom study, an artificial coronary artery was translated at velocities corresponding to 0, < 60, and 60-75 beats per minute (bpm) within an anthropomorphic phantom. The density of calcifications was 100 (very low), 200 (low), 400 (medium), and 800 (high) mgHA/cm3, respectively. CCTA was reconstructed with the following parameters: virtual non-iodine (VNI), with and without iterative reconstruction (QIR level 2, QIR off, respectively); kernels Qr36 and Qr44f; slice thickness/increment 3.0/1.5 mm and 0.4/0.2 mm. The agreement in risk group classification between CACCCTA and CACCSCT scoring was measured using Cohen weighted linear κ with 95% CI.For CCTA reconstructed with 0.4 mm slice thickness, calcium detectability was perfect (100%). At < 60 bpm, CACCCTA of low, and medium density calcification was underestimated by 53%, and 15%, respectively. However, CACCCTA was not significantly different from CACCSCT of very low, and high-density calcifications. The best risk agreement was achieved when CCTA was reconstructed with QIR off, Qr44f, and 0.4 mm slice thickness (κ = 0.762, 95% CI 0.671-0.853).In this dynamic phantom study, the detection of calcifications with different densities was excellent with CCTA on PCCT using thin-slice VNI reconstruction. Agatston scores were underestimated compared to CSCT but agreement in risk classification was substantial.Photon counting CT may enable the implementation of coronary artery calcium scoring from coronary CTA in daily clinical practice.Photon-counting CTA allows for excellent detectability of low-density calcifications at all heart rates. Coronary artery calcium scoring from coronary CTA acquired on photon counting CT is feasible, although improvement is needed. Adoption of the standard acquisition and reconstruction protocol for calcium scoring is needed for improved quantification of coronary artery calcium to fully employ the potential of photon counting CT.

  View details for DOI 10.1007/s00330-024-10806-4

  View details for PubMedID 38789792

  View details for PubMedCentralID 8270810

• 3D Printing for the Development of Palatal Defect Prosthetics. Federal practitioner : for the health care professionals of the VA, DoD, and PHS Calderon, C., Golzar, A., Marcott, S., Gifford, K., Napel, S., Fleischmann, D., Baik, F. M., Osborne, T. F., Finegersh, A., Sirjani, D. 2024; 41 (Suppl 2): S3-S7

  Abstract

  Three-dimensional (3D) printing has emerged as a promising new technology for the development of surgical prosthetics. Research in orthopedic surgery has demonstrated that using 3D printed customized prosthetics results in more precise implant placements and better patient outcomes. However, there has been little research on implementing customized 3D printed prosthetics in otolaryngology. The program sought to determine whether computed tomography (CT) serves as feasible templates to construct 3D printed palatal obturator prosthetics for defects in patients who have been treated for head and neck cancers.A retrospective review of patients with palatal defects was conducted and identified 1 patient with high quality CTs compatible with 3D modeling. CTs of the patient's craniofacial anatomy were used to develop a 3D model and a Formlabs 3B+ printer printed the palatal prosthetic. We successfully developed and produced an individualized prosthetic using CTs from a veteran with head and neck deformities caused by cancer treatment who was previously treated at the Veterans Affairs Palo Alto Health Care System. This project was successful in printing patient-specific implants using CT reproductions of the patient's craniofacial anatomy, particularly of the palate. The program was a proof of concept and the implant we created was not used on the patient.Customized 3D printed implants may allow otolaryngologists to enhance the performance and efficiency of surgeries and better rehabilitate and reconstruct craniofacial deformities to restore appearance and function to patients. Additional research will strive to enhance the therapeutic potential of these prosthetics to serve as low-cost, patient-specific implants.

  View details for DOI 10.12788/fp.0464

  View details for PubMedID 38813248

  View details for PubMedCentralID PMC11132111

• Pulmonary interstitial lymphography: A prospective trial with potential impact on stereotactic ablative radiotherapy planning for early-stage lung cancer. Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology Ko, R. B., Abelson, J. A., Fleischmann, D., Louie, J. D., Hwang, G. L., Sze, D. Y., Schuler, E., Kielar, K. N., Maxim, P. G., Le, Q., Hara, W. H., Diehn, M., Kothary, N., Loo, B. W. 2023: 110079

  Abstract

  This prospective feasibility trial investigated pulmonary interstitial lymphography to identify thoracic primary nodal drainage (PND). A post-hoc analysis of nodal recurrences was compared with PND for patients with early-stage lung cancer; larger studies are needed to establish correlation. Exploratory PND-inclusive stereotactic ablative radiotherapy plans were assessed for dosimetric feasibility.

  View details for DOI 10.1016/j.radonc.2023.110079

  View details for PubMedID 38163486

• Transfemoral tricuspid valve replacement and one-year outcomes: the TRISCEND study. European heart journal Kodali, S., Hahn, R. T., Makkar, R., Makar, M., Davidson, C. J., Puthumana, J. J., Zahr, F., Chadderdon, S., Fam, N., Ong, G., Yadav, P., Thourani, V., Vannan, M. A., O'Neill, W. W., Wang, D. D., Tchétché, D., Dumonteil, N., Bonfils, L., Lepage, L., Smith, R., Grayburn, P. A., Sharma, R. P., Haeffele, C., Babaliaros, V., Gleason, P. T., Elmariah, S., Inglessis-Azuaje, I., Passeri, J., Herrmann, H. C., Silvestry, F. E., Lim, S., Fowler, D., Webb, J. G., Moss, R., Modine, T., Lafitte, S., Latib, A., Ho, E., Goldberg, Y., Shah, P., Nyman, C., Rodés-Cabau, J., Bédard, E., Brugger, N., Sannino, A., Mack, M. J., Leon, M. B., Windecker, S. 2023

  Abstract

  For patients with symptomatic, severe tricuspid regurgitation (TR), early results of transcatheter tricuspid valve (TV) intervention studies have shown significant improvements in functional status and quality of life associated with right-heart reverse remodelling. Longer-term follow-up is needed to confirm sustained improvements in these outcomes.The prospective, single-arm, multicentre TRISCEND study enrolled 176 patients to evaluate the safety and performance of transcatheter TV replacement in patients with ≥moderate, symptomatic TR despite medical therapy. Major adverse events, reduction in TR grade and haemodynamic outcomes by echocardiography, and clinical, functional, and quality-of-life parameters are reported to one year.Enrolled patients were 71.0% female, mean age 78.7 years, 88.0% ≥ severe TR, and 75.4% New York Heart Association classes III-IV. Tricuspid regurgitation was reduced to ≤mild in 97.6% (P < .001), with increases in stroke volume (10.5 ± 16.8 mL, P < .001) and cardiac output (0.6 ± 1.2 L/min, P < .001). New York Heart Association class I or II was achieved in 93.3% (P < .001), Kansas City Cardiomyopathy Questionnaire score increased by 25.7 points (P < .001), and six-minute walk distance increased by 56.2 m (P < .001). All-cause mortality was 9.1%, and 10.2% of patients were hospitalized for heart failure.In an elderly, highly comorbid population with ≥moderate TR, patients receiving transfemoral EVOQUE transcatheter TV replacement had sustained TR reduction, significant increases in stroke volume and cardiac output, and high survival and low hospitalization rates with improved clinical, functional, and quality-of-life outcomes to one year. Funded by Edwards Lifesciences, TRISCEND ClinicalTrials.gov number, NCT04221490.

  View details for DOI 10.1093/eurheartj/ehad667

  View details for PubMedID 37930776

• Longitudinal investigation of aortic dissection in mice with computational fluid dynamics. Computer methods in biomechanics and biomedical engineering Bäumler, K., Phillips, E. H., Grande Gutiérrez, N., Fleischmann, D., Marsden, A. L., Goergen, C. J. 2023: 1-14

  Abstract

  Predicting late adverse events in aortic dissections is challenging. One commonly observed risk factor is partial thrombosis of the false lumen. In this study we investigated false lumen thrombus progression over 7 days in four mice with angiotensin II-induced aortic dissection. We performed computational fluid dynamic simulations with subject-specific boundary conditions from velocity and pressure measurements. We investigated endothelial cell activation potential, mean velocity, thrombus formation potential, and other hemodynamic factors. Our findings support the hypothesis that flow stagnation is the predominant hemodynamic factor driving a large thrombus ratio in false lumina, particularly those with a single fenestration.

  View details for DOI 10.1080/10255842.2023.2274281

  View details for PubMedID 37897230

• Automated cross-sectional view selection in CT angiography of aortic dissections with uncertainty awareness and retrospective clinical annotations. Computers in biology and medicine Pepe, A., Egger, J., Codari, M., Willemink, M. J., Gsaxner, C., Li, J., Roth, P. M., Schmalstieg, D., Mistelbauer, G., Fleischmann, D. 2023; 165: 107365

  Abstract

  Surveillance imaging of patients with chronic aortic diseases, such as aneurysms and dissections, relies on obtaining and comparing cross-sectional diameter measurements along the aorta at predefined aortic landmarks, over time. The orientation of the cross-sectional measuring planes at each landmark is currently defined manually by highly trained operators. Centerline-based approaches are unreliable in patients with chronic aortic dissection, because of the asymmetric flow channels, differences in contrast opacification, and presence of mural thrombus, making centerline computations or measurements difficult to generate and reproduce. In this work, we present three alternative approaches - INS, MCDS, MCDbS - based on convolutional neural networks and uncertainty quantification methods to predict the orientation (ϕ,θ) of such cross-sectional planes. For the monitoring of chronic aortic dissections, we show how a dataset of 162 CTA volumes with overall 3273 imperfect manual annotations routinely collected in a clinic can be efficiently used to accomplish this task, despite the presence of non-negligible interoperator variabilities in terms of mean absolute error (MAE) and 95% limits of agreement (LOA). We show how, despite the large limits of agreement in the training data, the trained model provides faster and more reproducible results than either an expert user or a centerline method. The remaining disagreement lies within the variability produced by three independent expert annotators and matches the current state of the art, providing a similar error, but in a fraction of the time.

  View details for DOI 10.1016/j.compbiomed.2023.107365

  View details for PubMedID 37647783

• Early clinical outcomes and molecular smooth muscle cell phenotyping using a prophylactic aortic arch replacement strategy in Loeys-Dietz syndrome. The Journal of thoracic and cardiovascular surgery Pedroza, A. J., Cheng, P., Dalal, A. R., Baeumler, K., Kino, A., Tognozzi, E., Shad, R., Yokoyama, N., Nakamura, K., Mitchel, O., Hiesinger, W., MacFarlane, E. G., Fleischmann, D., Woo, Y. J., Quertermous, T., Fischbein, M. P. 2023

  Abstract

  Loeys-Dietz syndrome (LDS) patients demonstrate heightened risk of distal thoracic aortic events after valve-sparing aortic root replacement (VSARR). This study assesses the clinical risks and hemodynamic consequences of a prophylactic aortic arch replacement strategy in LDS and characterizes smooth muscle cell (SMC) phenotype in LDS aneurysmal and normal-sized downstream aorta.Patients with genetically confirmed LDS (n=8) underwent prophylactic aortic arch replacement during VSARR. 4D flow magnetic resonance imaging (MRI) studies were performed in n=4 LDS patients (VSARR+arch) and compared with both contemporary Marfan syndrome patients (VSARR only, n=5) and control patients (without aortopathy, n=5). Aortic tissues from n=4 LDS patients and n=2 organ donors were processed for anatomically segmented single-cell RNA sequencing (scRNAseq) and histologic assessment.LDS VSARR+arch patients had no deaths, major morbidity, or aortic events in median 2.00 years follow-up. 4D-MRI demonstrated altered flow parameters in post-operative aortopathy patients relative to controls, but no clear deleterious changes attributable to arch replacement. Integrated analysis of aortic scRNAseq data (>49,000 cells) identified a continuum of abnormal SMC phenotypic modulation in LDS defined by reduced contractility and enriched extracellular matrix synthesis, adhesion receptors, and transforming growth factor-beta signaling. These 'modulated SMCs' populated the LDS tunica media with gradually reduced density from the overtly aneurysmal root to the non-dilated arch.LDS patients demonstrated excellent surgical outcomes without overt downstream flow or shear stress disturbances after concomitant VSARR+arch operations. Abnormal SMC-mediated aortic remodeling occurs within the normal diameter, clinically at-risk LDS arch segment. These initial clinical and pathophysiologic findings support concomitant arch replacement in LDS.

  View details for DOI 10.1016/j.jtcvs.2023.07.023

  View details for PubMedID 37500053

• Vendor Independent Coronary Calcium Scoring Improves Individual Risk Assessment: The Multi-Ethnic Study of Atherosclerosis (MESA). JACC. Cardiovascular imaging van der Werf, N. R., Dobrolinska, M. M., Greuter, M. J., Willemink, M. J., Fleischmann, D., Bos, D., Slart, R. H., Budoff, M., Leiner, T. 2023

  Abstract

  Substantial variation in Agatston scores (AS) acquired with different computed tomography (CT) scanners may influence patient risk classification.This study sought to develop a calibration tool for state-of-the-art CT systems resulting in vendor-neutral AS (vnAS), and to assess the impact of vnAS on coronary heart disease (CHD) event prediction.The vnAS calibration tool was derived by imaging 2 anthropomorphic calcium containing phantoms on 7 different CT and 1 electron beam tomography system, which was used as the reference system. The effect of vnAS on CHD event prediction was analyzed with data from 3,181 participants from MESA (Multi-Ethnic Study on Atherosclerosis). Chi-square analysis was used to compare CHD event rates between low (vnAS <100) and high calcium groups (vnAS ≥100). Multivariable Cox proportional hazard regression models were used to assess the incremental value of vnAS.For all CT systems, a strong correlation with electron beam tomography-AS was found (R2 >0.932). Of the MESA participants originally in the low calcium group (n = 781), 85 (11%) participants were reclassified to a higher risk category based on the recalculated vnAS. For reclassified participants, the CHD event rate of 15% was significantly higher compared with participants in the low calcium group (7%; P = 0.008) with a CHD HR of 3.39 (95% CI: 1.82-6.35; P = 0.001).The authors developed a calibration tool that enables calculation of a vnAS. MESA participants who were reclassified to a higher calcium category by means of the vnAS experienced more CHD events, indicating improved risk categorization.

  View details for DOI 10.1016/j.jcmg.2023.05.005

  View details for PubMedID 37318394

• Radiology: Cardiothoracic Imaging Highlights 2022. Radiology. Cardiothoracic imaging Mastrodicasa, D., Aquino, G. J., Ordovas, K. G., Vargas, D., Fleischmann, D., Abbara, S., Hanneman, K. 2023; 5 (3): e230042

  Abstract

  Since its inaugural issue in 2019, Radiology: Cardiothoracic Imaging has disseminated the latest scientific advances and technical developments in cardiac, vascular, and thoracic imaging. In this review, we highlight select articles published in this journal between October 2021 and October 2022. The scope of the review encompasses various aspects of coronary artery and congenital heart diseases, vascular diseases, thoracic imaging, and health services research. Key highlights include changes in the revised Coronary Artery Disease Reporting and Data System 2.0, the value of coronary CT angiography in informing prognosis and guiding treatment decisions, cardiac MRI findings after COVID-19 vaccination or infection, high-risk features at CT angiography to identify patients with aortic dissection at risk for late adverse events, and CT-guided fiducial marker placement for preoperative planning for pulmonary nodules. Ongoing research and future directions include photon-counting CT and artificial intelligence applications in cardiovascular imaging. Keywords: Pediatrics, CT Angiography, CT-Perfusion, CT-Spectral Imaging, MR Angiography, PET/CT, Transcatheter Aortic Valve Implantation/Replacement (TAVI/TAVR), Cardiac, Pulmonary, Vascular, Aorta, Coronary Arteries © RSNA, 2023.

  View details for DOI 10.1148/ryct.230042

  View details for PubMedID 37404783

  View details for PubMedCentralID PMC10316293

• Reduced Pulmonary Artery Distensibility Predicts Persistent Pulmonary Hypertension and 2-Year Mortality in Patients with Severe Aortic Stenosis Undergoing TAVR. Academic radiology Turner, V., Maret, E., Kim, J. B., Codari, M., Hinostroza, V., Mastrodicasa, D., Watkins, A. C., Fearon, W. F., Fischbein, M. P., Haddad, F., Willemink, M. J., Fleischmann, D. 2023

  Abstract

  RATIONALE AND OBJECTIVES: Post-TAVR persistent pulmonary hypertension (PH) is a better predictor of poor outcome than pre-TAVR PH. In this longitudinal study we sought to evaluate whether pulmonary artery (distensibility (DPA) measured on preprocedural ECG-gated CTA is associated with persistent-PH and 2-year mortality after TAVR.MATERIALS AND METHODS: Three hundred and thirty-six patients undergoing TAVR between July 2012 and March 2016 were retrospectively included and followed for all-cause mortality until November 2017. All patients underwent retrospectively ECG-gated CTA prior to TAVR. Main pulmonary artery (MPA) area was measured in systole and in diastole. DPA was calculated as: [(area-MPAmax-area-MPAmin)/area-MPAmax]%. ROC analysis was performed to assess the AUC for persistent-PH. Youden Index was used to determine the optimal threshold of DPA for persistent-PH. Two groups were compared based on a DPA threshold of 8% (specificity of 70% for persistent-PH). Kaplan-Meier, Cox proportional-hazard, and logistic regression analyses were performed. The primary clinical endpoint was defined as persistent-PH post-TAVR. The secondary endpoint was defined as all-cause mortality 2 years after TAVR.RESULTS: Median follow-up time was 413 (interquartiles 339-757) days. A total of 183 (54%) had persistent-PH and 68 (20%) patients died within 2-years after TAVR. Patients with DPA<8% had significantly more persistent-PH (67% vs 47%, p<0.001) and 2-year deaths (28% vs 15%, p=0.006), compared to patients with DPA>8%. Adjusted multivariable regression analyses showed that DPA<8% was independently associated with persistent-PH (OR 2.10 [95%-CI 1.3-4.5], p=0.007) and 2-year mortality (HR 2.91 [95%-CI 1.5-5.8], p=0.002). Kaplan-Meier analysis showed that 2-year mortality of patients with DPA<8% was significantly higher compared to patients with DPA≥8% (mortality 28% vs 15%; log-rank p=0.003).CONCLUSION: DPA on preprocedural CTA is independently associated with persistent-PH and two-year mortality in patients who undergo TAVR.

  View details for DOI 10.1016/j.acra.2023.03.014

  View details for PubMedID 37147161

• Low Utility of Frequent Imaging Follow-up for Incidental Ascending Aortic Aneurysms. Radiology. Cardiothoracic imaging Shen, J., Fleischmann, D. 2023; 5 (2): e230092

  View details for DOI 10.1148/ryct.230092

  View details for PubMedID 37124641

  View details for PubMedCentralID PMC10141449

• Hemodynamic Effects of Entry and Exit Tear Size in Aortic Dissection Evaluated with In Vitro Magnetic Resonance Imaging and Fluid-Structure Interaction Simulation. ArXiv Zimmermann, J., Bäumler, K., Loecher, M., Cork, T. E., Marsden, A. L., Ennis, D. B., Fleischmann, D. 2023

  Abstract

  Understanding the complex interplay between morphologic and hemodynamic features in aortic dissection is critical for risk stratification and for the development of individualized therapy. This work evaluates the effects of entry and exit tear size on the hemodynamics in type B aortic dissection by comparing fluid-structure interaction (FSI) simulations with in vitro 4D-flow magnetic resonance imaging (MRI). A baseline patient-specific 3D-printed model and two variants with modified tear size (smaller entry tear, smaller exit tear) were embedded into a flow- and pressure-controlled setup to perform MRI as well as 12-point catheter-based pressure measurements. The same models defined the wall and fluid domains for FSI simulations, for which boundary conditions were matched with measured data. Results showed exceptionally well matched complex flow patterns between 4D-flow MRI and FSI simulations. Compared to the baseline model, false lumen flow volume decreased with either a smaller entry tear (-17.8 and -18.5 %, for FSI simulation and 4D-flow MRI, respectively) or smaller exit tear (-16.0 and -17.3 %). True to false lumen pressure difference (initially 11.0 and 7.9 mmHg, for FSI simulation and catheter-based pressure measurements, respectively) increased with a smaller entry tear (28.9 and 14.6 mmHg), and became negative with a smaller exit tear (-20.6 and -13.2 mmHg). This work establishes quantitative and qualitative effects of entry or exit tear size on hemodynamics in aortic dissection, with particularly notable impact observed on FL pressurization. FSI simulations demonstrate acceptable qualitative and quantitative agreement with flow imaging, supporting its deployment in clinical studies.

  View details for DOI 10.1161/HCI.0000000000000075

  View details for PubMedID 36994169

  View details for PubMedCentralID PMC10055490

• Deep Learning Image Reconstruction for CT: Technical Principles and Clinical Prospects. Radiology Koetzier, L. R., Mastrodicasa, D., Szczykutowicz, T. P., van der Werf, N. R., Wang, A. S., Sandfort, V., van der Molen, A. J., Fleischmann, D., Willemink, M. J. 2023: 221257

  Abstract

  Filtered back projection (FBP) has been the standard CT image reconstruction method for 4 decades. A simple, fast, and reliable technique, FBP has delivered high-quality images in several clinical applications. However, with faster and more advanced CT scanners, FBP has become increasingly obsolete. Higher image noise and more artifacts are especially noticeable in lower-dose CT imaging using FBP. This performance gap was partly addressed by model-based iterative reconstruction (MBIR). Yet, its "plastic" image appearance and long reconstruction times have limited widespread application. Hybrid iterative reconstruction partially addressed these limitations by blending FBP with MBIR and is currently the state-of-the-art reconstruction technique. In the past 5 years, deep learning reconstruction (DLR) techniques have become increasingly popular. DLR uses artificial intelligence to reconstruct high-quality images from lower-dose CT faster than MBIR. However, the performance of DLR algorithms relies on the quality of data used for model training. Higher-quality training data will become available with photon-counting CT scanners. At the same time, spectral data would greatly benefit from the computational abilities of DLR. This review presents an overview of the principles, technical approaches, and clinical applications of DLR, including metal artifact reduction algorithms. In addition, emerging applications and prospects are discussed.

  View details for DOI 10.1148/radiol.221257

  View details for PubMedID 36719287

• Hemodynamic Effects of Entry Versus Exit Tear Size and Tissue Stiffness in Simulations of Aortic Dissection Baumler, K., Zimmermann, J., Ennis, D. B., Marsden, A. L., Fleischmann, D., Tavares, J. M., Bourauel, C., Geris, L., Slote, J. V. SPRINGER INTERNATIONAL PUBLISHING AG. 2023: 143-152

  View details for DOI 10.1007/978-3-031-10015-4_13

  View details for Web of Science ID 000876827700013

• Limited Aortic Intimal Tears: CT Imaging Features and Clinical Characteristics. Radiology. Cardiothoracic imaging Madani, M. H., Turner, V. L., Hallett, R. L., Willemink, M. J., Murillo, H., Chin, A. S., Berry, G. J., Fleischmann, D. 2022; 4 (6): e220155

  Abstract

  Limited aortic intimal tear is an uncommon lesion of the dissection spectrum. The lesion has several imaging features that are not well known, including asymmetric aortic contour abnormalities, filling defects, and various morphologic patterns, such as linear, L-shaped, T-shaped, and stellate configurations. Hemorrhage of the aortic wall may also be present in patients with this rare entity. This imaging essay reviews the CT imaging findings and clinical characteristics of patients with limited intimal tears. Keywords: Aorta, CT © RSNA, 2022.

  View details for DOI 10.1148/ryct.220155

  View details for PubMedID 36601454

  View details for PubMedCentralID PMC9806729

• Thoracic Endovascular Aortic Repair for Chronic Type B Aortic Dissection: Pre- and Postprocedural Imaging. Radiographics : a review publication of the Radiological Society of North America, Inc Shen, J., Mastrodicasa, D., Al Bulushi, Y., Lin, M. C., Tse, J. R., Watkins, A. C., Lee, J. T., Fleischmann, D. 2022; 42 (6): 1638-1653

  Abstract

  Aortic dissection is a chronic disease that requires lifelong clinical and imaging surveillance, long after the acute event. Imaging has an important role in prognosis, timing of repair, device sizing, and monitoring for complications, especially in the endovascular therapy era. Important anatomic features at preprocedural imaging include the location of the primary intimal tear and aortic zonal and branch vessel involvement, which influence the treatment strategy. Challenges of repair in the chronic phase include a small true lumen in conjunction with a stiff intimal flap, complex anatomy, and retrograde perfusion from distal reentry tears. The role of thoracic endovascular aortic repair (TEVAR) remains controversial for treatment of chronic aortic dissection. Standard TEVAR is aimed at excluding the primary intimal tear to decrease false lumen perfusion, induce false lumen thrombosis, promote aortic remodeling, and prevent aortic growth. In addition to covering the primary intimal tear with an endograft, several adjunctive techniques have been developed to mitigate retrograde false lumen perfusion. These techniques are broadly categorized into false lumen obliteration and landing zone optimization strategies, such as the provisional extension to induce complete attachment (PETTICOAT), false lumen embolization, cheese-wire fenestration, and knickerbocker techniques. Familiarity with these techniques is important to recognize expected changes and complications at postintervention imaging. The authors detail imaging options, provide examples of simple and complex endovascular repairs of aortic dissections, and highlight complications that can be associated with various techniques. Online supplemental material is available for this article. ©RSNA, 2022.

  View details for DOI 10.1148/rg.220028

  View details for PubMedID 36190862

• Imaging Challenges in Chronic Dissection. Seminars in roentgenology Shen, J., Mastrodicasa, D., Tse, J. R., Fleischmann, D. 2022; 57 (4): 345-356

  Abstract

  Chronic aortic dissection comprises a heterogeneous group of unrepaired and repaired disease requiring lifelong clinical and imaging surveillance. CT and MRI are the main imaging modalities for longitudinal surveillance, with growing interest in emerging imaging techniques for prognostic potential. Imaging difficulties span technical and diagnostic challenges, some of which are unique to the repaired aorta, with specific complications depending on the type of repair. This review describes existing and emerging imaging techniques, outlines the technical and diagnostic challenges encountered at CT and MRI, and highlights the diagnostic pitfalls of chronic aortic dissection.

  View details for DOI 10.1053/j.ro.2022.06.002

  View details for PubMedID 36265986

• Artificial Intelligence Applications in Aortic Dissection Imaging. Seminars in roentgenology Mastrodicasa, D., Codari, M., Bäumler, K., Sandfort, V., Shen, J., Mistelbauer, G., Hahn, L. D., Turner, V. L., Desjardins, B., Willemink, M. J., Fleischmann, D. 2022; 57 (4): 357-363

  View details for DOI 10.1053/j.ro.2022.07.001

  View details for PubMedID 36265987

• Inter-observer variability of expert-derived morphologic risk predictors in aortic dissection. European radiology Willemink, M. J., Mastrodicasa, D., Madani, M. H., Codari, M., Chepelev, L. L., Mistelbauer, G., Hanneman, K., Ouzounian, M., Ocazionez, D., Afifi, R. O., Lacomis, J. M., Lovato, L., Pacini, D., Folesani, G., Hinzpeter, R., Alkadhi, H., Stillman, A. E., Sailer, A. M., Turner, V. L., Hinostroza, V., Baumler, K., Chin, A. S., Burris, N. S., Miller, D. C., Fischbein, M. P., Fleischmann, D. 2022

  Abstract

  OBJECTIVES: Establishing the reproducibility of expert-derived measurements on CTA exams of aortic dissection is clinically important and paramount for ground-truth determination for machine learning.METHODS: Four independent observers retrospectively evaluated CTA exams of 72 patients with uncomplicated Stanford type B aortic dissection and assessed the reproducibility of a recently proposed combination of four morphologic risk predictors (maximum aortic diameter, false lumen circumferential angle, false lumen outflow, and intercostal arteries). For the first inter-observer variability assessment, 47 CTA scans from one aortic center were evaluated by expert-observer 1 in an unconstrained clinical assessment without a standardized workflow and compared to a composite of three expert-observers (observers 2-4) using a standardized workflow. A second inter-observer variability assessment on 30 out of the 47 CTA scans compared observers 3 and 4 with a constrained, standardized workflow. A third inter-observer variability assessment was done after specialized training and tested between observers 3 and 4 in an external population of 25 CTA scans. Inter-observer agreement was assessed with intraclass correlation coefficients (ICCs) and Bland-Altman plots.RESULTS: Pre-training ICCs of the four morphologic features ranged from 0.04 (-0.05 to 0.13) to 0.68 (0.49-0.81) between observer 1 and observers 2-4 and from 0.50 (0.32-0.69) to 0.89 (0.78-0.95) between observers 3 and 4. ICCs improved after training ranging from 0.69 (0.52-0.87) to 0.97 (0.94-0.99), and Bland-Altman analysis showed decreased bias and limits of agreement.CONCLUSIONS: Manual morphologic feature measurements on CTA images can be optimized resulting in improved inter-observer reliability. This is essential for robust ground-truth determination for machine learning models.KEY POINTS: Clinical fashion manual measurements of aortic CTA imaging features showed poor inter-observer reproducibility. A standardized workflow with standardized training resulted in substantial improvements with excellent inter-observer reproducibility. Robust ground truth labels obtained manually with excellent inter-observer reproducibility are key to develop reliable machine learning models.

  View details for DOI 10.1007/s00330-022-09056-z

  View details for PubMedID 36029344

• Association of left ventricular diastolic function with coronary artery calcium score: A Project Baseline Health Study. Journal of cardiovascular computed tomography Haddad, F., Cauwenberghs, N., Daubert, M. A., Kobayashi, Y., Bloomfield, G. S., Fleischman, D., Koweek, L., Maron, D. J., Rodriguez, F., Liao, Y. J., Moneghetti, K., Amsallem, M., Mega, J., Hernandez, A., Califf, R., Mahaffey, K. W., Shah, S. H., Kuznetsova, T., Douglas, P. S., Project Baseline Health Study Investigators 2022

  Abstract

  BACKGROUND: Coronary artery calcium (CAC) and left ventricular diastolic dysfunction (LVDD) are strong predictors of cardiovascular events and share common risk factors. However, their independent association remains unclear.METHODS: In the Project Baseline Health Study (PBHS), 2082 participants underwent cardiac-gated, non-contrast chest computed tomography (CT) and echocardiography. The association between left ventricular (LV) diastolic function and CAC was assessed using multidimensional network and multivariable-adjusted regression analyses. Multivariable analysis was conducted on continuous LV diastolic parameters and categorical classification of LVDD and adjusted for traditional cardiometabolic risk factors. LVDD was defined using reference limits from a low-risk reference group without established cardiovascular disease, cardiovascular risk factors or evidence of CAC, (n​=​560). We also classified LVDD using the American Society of Echocardiography recommendations.RESULTS: The mean age of the participants was 51​±​17 years with 56.6% female and 62.6% non-Hispanic White. Overall, 38.1% had hypertension; 13.7% had diabetes; and 39.9% had CAC >0. An intertwined network was observed between diastolic parameters, CAC score, age, LV mass index, and pulse pressure. In the multivariable-adjusted analysis, e', E/e', and LV mass index were independently associated with CAC after adjustment for traditional risk factors. For both e' and E/e', the effect size and statistical significance were higher across increasing CAC tertiles. Other independent correlates of e' and E/e' included age, female sex, Black race, height, weight, pulse pressure, hemoglobin A1C, and HDL cholesterol. The independent association with CAC was confirmed using categorical analysis of LVDD, which occurred in 554 participants (26.6%) using population-derived thresholds.CONCLUSION: In the PBHS study, the subclinical coronary atherosclerotic disease burden detected using CAC scoring was independently associated with diastolic function.CLINICALTRIALS: GOV IDENTIFIER: NCT03154346.

  View details for DOI 10.1016/j.jcct.2022.06.003

  View details for PubMedID 35872137

• Blood Flow Patterns of Risk in AorticDissection: Time to Go With the Flow? Journal of the American College of Cardiology Burris, N. S., Fleischmann, D., Hope, M. D. 2022; 79 (24): 2428-2430

  View details for DOI 10.1016/j.jacc.2022.04.023

  View details for PubMedID 35710194

• Tetralogy of Fallot and Aortic Dissection: Implications in Management. JACC. Case reports Vaikunth, S. S., Chan, J. L., Woo, J. P., Bykhovsky, M. R., Lui, G. K., Ma, M., Romfh, A. W., Lamberti, J., Mastrodicasa, D., Fleischmann, D., Fischbein, M. P. 2022; 4 (10): 581-586

  Abstract

  We present the case of a 61-year-old man with tetralogy of Fallot postrepair and mechanical aortic valve replacement with an aortic root/ascending/arch aneurysm with chronic type A aortic dissection. He underwent uncomplicated aortic root and total arch replacement. Continued surveillance for aortic aneurysm is necessary in the tetralogy of Fallot population. (Level of Difficulty: Intermediate.).

  View details for DOI 10.1016/j.jaccas.2022.02.021

  View details for PubMedID 35615213

• Low-dose coronary calcium scoring CT using a dedicated reconstruction filter for kV-independent calcium measurements. European radiology Jubran, A., Mastrodicasa, D., van Praagh, G. D., Willemink, M. J., Kino, A., Wang, J., Fleischmann, D., Nieman, K. 1800

  Abstract

  In this prospective, pilot study, we tested a kV-independent coronary artery calcium scoring CT protocol, using a novel reconstruction kernel (Sa36f). From December 2018 to November 2019, we performed an additional research scan in 61 patients undergoing clinical calcium scanning. For the standard protocol (120 kVp), images were reconstructed with a standard, medium-sharp kernel (Qr36d). For the research protocol (automated kVp selection), images were reconstructed with a novel kernel (Sa36f). Research scans were sequentially performed using a higher (cohort A, n=31) and a lower (cohort B, n=30) dose optimizer setting within the automatic system with customizable kV selection. Agatston scores, coronary calcium volumes, and radiation exposure of the standard and research protocol were compared. A phantom study was conducted to determine inter-scan variability. There was excellent correlation for the Agatston score between the two protocols (r=0.99); however, the standard protocol resulted in slightly higher Agatston scores (29.4 [0-139.0] vs 17.4 [0-158.2], p=0.028). The median calcium volumes were similar (11.5 [0-109.2] vs 11.2 [0-118.0] mm3; p=0.176), and the number of calcified lesions was not significantly different (p=0.092). One patient was reclassified to another risk category. The research protocol could be performed at a lower kV and resulted in a substantially lower radiation exposure, with a median volumetric CT dose index of 4.1 vs 5.2mGy, respectively (p<0.001). Our results showed that a consistent coronary calcium scoring can be achieved using a kV-independent protocol that lowers radiation doses compared to the standard protocol. KEY POINTS: The Sa36f kernel enables kV-independent Agatston scoring without changing the original Agatston weighting threshold. Agatston scores and calcium volumes of the standard and research protocols showed an excellent correlation. The research protocol resulted in a significant reduction in radiation exposure with a mean reduction of 22% in DLP and 25% in CTDIvol.

  View details for DOI 10.1007/s00330-021-08451-2

  View details for PubMedID 34989838

• Biological and clinical correlates of the patient health questionnaire-9: exploratory cross-sectional analyses of the baseline health study. BMJ open Califf, R. M., Wong, C., Doraiswamy, P. M., Hong, D. S., Miller, D. P., Mega, J. L. 2022; 12 (1): e054741

  Abstract

  We assessed the relationship between the Patient Health Questionnaire-9 (PHQ-9) at intake and other measurements intended to assess biological factors, markers of disease and health status.We performed a cross-sectional analysis of 2365 participants from the Baseline Health Study, a prospective cohort of adults selected to represent major demographic groups in the USA. Participants underwent deep phenotyping on demographic, clinical, laboratory, functional and imaging findings.Despite extensive research on the clinical implications of the PHQ-9, data are limited on the relationship between PHQ-9 scores and other measures of health and disease; we sought to better understand this relationship.None.Cross-sectional measures of medical illnesses, gait, balance strength, activities of daily living, imaging and laboratory tests.Compared with lower PHQ-9 scores, higher scores were associated with female sex (46.9%-66.7%), younger participants (53.6-42.4 years) and compromised physical status (higher resting heart rates (65 vs 75 bpm), larger body mass index (26.5-30 kg/m2), greater waist circumference (91-96.5 cm)) and chronic conditions, including gastro-oesophageal reflux disease (13.2%-24.7%) and asthma (9.5%-20.4%) (p<0.0001). Increasing PHQ-9 score was associated with a higher frequency of comorbidities (migraines (6%-20.4%)) and active symptoms (leg cramps (6.4%-24.7%), mood change (1.2%-47.3%), lack of energy (1.2%-57%)) (p<0.0001). After adjustment for relevant demographic, socioeconomic, behavioural and medical characteristics, we found that memory change, tension, shortness of breath and indicators of musculoskeletal symptoms (backache and neck pain) are related to higher PHQ-9 scores (p<0.0001).Our study highlights how: (1) even subthreshold depressive symptoms (measured by PHQ-9) may be indicative of several individual- and population-level concerns that demand more attention; and (2) depression should be considered a comorbidity in common disease.NCT03154346.

  View details for DOI 10.1136/bmjopen-2021-054741

  View details for PubMedID 34983769

• CT Angiography of Venoarterial Extracorporeal Membrane Oxygenation. Radiographics : a review publication of the Radiological Society of North America, Inc Shen, J., Tse, J. R., Chan, F., Fleischmann, D. 2021: 210079

  Abstract

  Imaging plays a central role in the workup of thromboembolic events and bleeding complications in patients treated with venoarterial extracorporeal membrane oxygenation (ECMO) (VA-ECMO), and radiologists should be familiar with the expected hemodynamic changes and flow-related artifacts associated with the VA-ECMO system. VA-ECMO is a form of temporary mechanical circulatory support for critically ill patients with acute, refractory cardiac or cardiopulmonary failure. As the use of VA-ECMO continues to increase, it is important to be aware of associated hemodynamic changes and challenges at imaging. Patients treated with VA-ECMO are at high risk for thromboembolic events and bleeding complications and, thus, often require evaluation with CT angiography (CTA). VA-ECMO can be implemented by using central or peripheral cannulation. The peripheral femorofemoral VA-ECMO circuit in particular alters the sequence and direction of contrast medium enhancement substantially, resulting in flow-related artifacts that can mimic or obscure disease at CTA. Nonopacification can be mistaken for spurious thrombus or simulate complete vascular occlusion, while mixing artifacts can mimic dissections. Misinterpretation of flow-related CTA artifacts can lead to inappropriate surgical or medical intervention. A methodical and multiphasic approach should be taken to CTA imaging strategies and interpretation for patients treated with VA-ECMO. There is no universal CTA protocol for patients on VA-ECMO. Each protocol must be designed for the study indication, with consideration of the configuration of the ECMO cannulas, contrast material injection site, region of interest, native cardiac output, and ECMO flow rate. The authors provide examples of common and unusual VA-ECMO-related artifacts, with a focus on strategies for optimizing CTA image acquisition. Online supplemental material is available for this article. ©RSNA, 2021.

  View details for DOI 10.1148/rg.210079

  View details for PubMedID 34890275

• Entry Tear Dominance at CT Angiography Predicts Long-term Clinical Outcomes in Aortic Dissection: Another Piece of the Puzzle. Radiology. Cardiothoracic imaging Fleischmann, D., Burris, N. 1800; 3 (6): e210271

  View details for DOI 10.1148/ryct.2021210271

  View details for PubMedID 34934955

• Coronary Artery Calcium Scoring: Toward a New Standard. Investigative radiology van Praagh, G. D., Wang, J., van der Werf, N. R., Greuter, M. J., Mastrodicasa, D., Nieman, K., van Hamersvelt, R. W., Oostveen, L. J., Lange, F. d., Slart, R. H., Leiner, T., Fleischmann, D., Willemink, M. J. 2021

  Abstract

  OBJECTIVES: Although the Agatston score is a commonly used quantification method, rescan reproducibility is suboptimal, and different CT scanners result in different scores. In 2007, McCollough et al (Radiology 2007;243:527-538) proposed a standard for coronary artery calcium quantification. Advancements in CT technology over the last decade, however, allow for improved acquisition and reconstruction methods. This study aims to investigate the feasibility of a reproducible reduced dose alternative of the standardized approach for coronary artery calcium quantification on state-of-the-art CT systems from 4 major vendors.MATERIALS AND METHODS: An anthropomorphic phantom containing 9 calcifications and 2 extension rings were used. Images were acquired with 4 state-of-the-art CT systems using routine protocols and a variety of tube voltages (80-120 kV), tube currents (100% to 25% dose levels), slice thicknesses (3/2.5 and 1/1.25 mm), and reconstruction techniques (filtered back projection and iterative reconstruction). Every protocol was scanned 5 times after repositioning the phantom to assess reproducibility. Calcifications were quantified as Agatston scores.RESULTS: Reducing tube voltage to 100 kV, dose to 75%, and slice thickness to 1 or 1.25 mm combined with higher iterative reconstruction levels resulted in an on average 36% lower intrascanner variability (interquartile range) compared with the standard 120 kV protocol. Interscanner variability per phantom size decreased by 34% on average. With the standard protocol, on average, 6.2 ± 0.4 calcifications were detected, whereas 7.0 ± 0.4 were detected with the proposed protocol. Pairwise comparisons of Agatston scores between scanners within the same phantom size demonstrated 3 significantly different comparisons at the standard protocol (P < 0.05), whereas no significantly different comparisons arose at the proposed protocol (P > 0.05).CONCLUSIONS: On state-of-the-art CT systems of 4 different vendors, a 25% reduced dose, thin-slice calcium scoring protocol led to improved intrascanner and interscanner reproducibility and increased detectability of small and low-density calcifications in this phantom. The protocol should be extensively validated before clinical use, but it could potentially improve clinical interscanner/interinstitutional reproducibility and enable more consistent risk assessment and treatment strategies.

  View details for DOI 10.1097/RLI.0000000000000808

  View details for PubMedID 34261083

• Machine Learning to Predict In-Hospital Mortality in COVID-19 Patients Using Computed Tomography-Derived Pulmonary and Vascular Features. Journal of personalized medicine Schiaffino, S., Codari, M., Cozzi, A., Albano, D., Ali, M., Arioli, R., Avola, E., Bna, C., Cariati, M., Carriero, S., Cressoni, M., Danna, P. S., Della Pepa, G., Di Leo, G., Dolci, F., Falaschi, Z., Flor, N., Foa, R. A., Gitto, S., Leati, G., Magni, V., Malavazos, A. E., Mauri, G., Messina, C., Monfardini, L., Pasche, A., Pesapane, F., Sconfienza, L. M., Secchi, F., Segalini, E., Spinazzola, A., Tombini, V., Tresoldi, S., Vanzulli, A., Vicentin, I., Zagaria, D., Fleischmann, D., Sardanelli, F. 2021; 11 (6)

  Abstract

  Pulmonary parenchymal and vascular damage are frequently reported in COVID-19 patients and can be assessed with unenhanced chest computed tomography (CT), widely used as a triaging exam. Integrating clinical data, chest CT features, and CT-derived vascular metrics, we aimed to build a predictive model of in-hospital mortality using univariate analysis (Mann-Whitney U test) and machine learning models (support vectors machines (SVM) and multilayer perceptrons (MLP)). Patients with RT-PCR-confirmed SARS-CoV-2 infection and unenhanced chest CT performed on emergency department admission were included after retrieving their outcome (discharge or death), with an 85/15% training/test dataset split. Out of 897 patients, the 229 (26%) patients who died during hospitalization had higher median pulmonary artery diameter (29.0 mm) than patients who survived (27.0 mm, p < 0.001) and higher median ascending aortic diameter (36.6 mm versus 34.0 mm, p < 0.001). SVM and MLP best models considered the same ten input features, yielding a 0.747 (precision 0.522, recall 0.800) and 0.844 (precision 0.680, recall 0.567) area under the curve, respectively. In this model integrating clinical and radiological data, pulmonary artery diameter was the third most important predictor after age and parenchymal involvement extent, contributing to reliable in-hospital mortality prediction, highlighting the value of vascular metrics in improving patient stratification.

  View details for DOI 10.3390/jpm11060501

  View details for PubMedID 34204911

• Implicit Modeling of Patient-Specific Aortic Dissections with Elliptic Fourier Descriptors COMPUTER GRAPHICS FORUM Mistelbauer, G., Rossl, C., Baeumler, K., Preim, B., Fleischmann, D. 2021; 40 (3): 423-434

  View details for DOI 10.1111/cgf.14318

  View details for Web of Science ID 000667924000035

• An international survey on AI in radiology in 1041 radiologists and radiology residents part 2: expectations, hurdles to implementation, and education. European radiology Huisman, M., Ranschaert, E., Parker, W., Mastrodicasa, D., Koci, M., Pinto de Santos, D., Coppola, F., Morozov, S., Zins, M., Bohyn, C., Koc, U., Wu, J., Veean, S., Fleischmann, D., Leiner, T., Willemink, M. J. 2021

  Abstract

  OBJECTIVES: Currently, hurdles to implementation of artificial intelligence (AI) in radiology are a much-debated topic but have not been investigated in the community at large. Also, controversy exists if and to what extent AI should be incorporated into radiology residency programs.METHODS: Between April and July 2019, an international survey took place on AI regarding its impact on the profession and training. The survey was accessible for radiologists and residents and distributed through several radiological societies. Relationships of independent variables with opinions, hurdles, and education were assessed using multivariable logistic regression.RESULTS: The survey was completed by 1041 respondents from 54 countries. A majority (n = 855, 82%) expects that AI will cause a change to the radiology field within 10 years. Most frequently, expected roles of AI in clinical practice were second reader (n = 829, 78%) and work-flow optimization (n = 802, 77%). Ethical and legal issues (n = 630, 62%) and lack of knowledge (n = 584, 57%) were mentioned most often as hurdles to implementation. Expert respondents added lack of labelled images and generalizability issues. A majority (n = 819, 79%) indicated that AI should be incorporated in residency programs, while less support for imaging informatics and AI as a subspecialty was found (n = 241, 23%).CONCLUSIONS: Broad community demand exists for incorporation of AI into residency programs. Based on the results of the current study, integration of AI education seems advisable for radiology residents, including issues related to data management, ethics, and legislation.KEY POINTS: There is broad demand from the radiological community to incorporate AI into residency programs, but there is less support to recognize imaging informatics as a radiological subspecialty. Ethical and legal issues and lack of knowledge are recognized as major bottlenecks for AI implementation by the radiological community, while the shortage in labeled data and IT-infrastructure issues are less often recognized as hurdles. Integrating AI education in radiology curricula including technical aspects of data management, risk of bias, and ethical and legal issues may aid successful integration of AI into diagnostic radiology.

  View details for DOI 10.1007/s00330-021-07782-4

  View details for PubMedID 33974148

• Fully Automated Quantification Method (FQM) of Coronary Calcium in an Anthropomorphic Phantom. Medical physics van Praagh, G. D., van der Werf, N. R., Wang, J., van Ommen, F., Poelhekken, K., Slart, R. H., Fleischmann, D., Greuter, M. J., Leiner, T., Willemink, M. J. 2021

  Abstract

  OBJECTIVE: Coronary artery calcium (CAC) score is a strong predictor for future adverse cardiovascular events. Anthropomorphic phantoms are often used for CAC studies on computed tomography (CT) to allow for evaluation or variation of scanning or reconstruction parameters within or across scanners against a reference standard. This often results in large number of datasets. Manual assessment of these large datasets is time consuming and cumbersome. Therefore, this study aimed to develop and validate a fully automated, open-source quantification method (FQM) for coronary calcium in a standardized phantom.MATERIALS AND METHODS: A standard, commercially available anthropomorphic thorax phantom was used with an insert containing nine calcifications with different sizes and densities. To simulate two different patient sizes, an extension ring was used. Image data was acquired with four state-of-the-art CT systems using routine CAC scoring acquisition protocols. For inter-scan variability, each acquisition was repeated five times with small translations and/or rotations. Vendor-specific CAC scores (Agatston, volume, and mass) were calculated as reference scores using vendor-specific software. Both the international standard CAC quantification methods as well as vendor-specific adjustments were implemented in FQM. Reference and FQM scores were compared using Bland-Altman analysis, intraclass correlation coefficients, risk reclassifications, and Cohen's kappa. Also, robustness of FQM was assessed using varied acquisitions and reconstruction settings and validation on a dynamic phantom. Further, image quality metrics were implemented: noise power spectrum, task transfer function, and contrast- and signal-to-noise ratio among others. Results were validated using imQuest software.RESULTS: Three parameters in CAC scoring methods varied among the different vendor-specific software packages: the Hounsfield unit (HU) threshold, the minimum area used to designate a group of voxels as calcium, and the usage of isotropic voxels for the volume score. The FQM was in high agreement with vendor-specific scores and ICC's (median [95% CI]) were excellent (1.000 [0.999-1.000] to 1.000 [1.000-1.000]). An excellent inter-platform reliability of kappa = 0.969 and kappa = 0.973 was found. TTF results gave a maximum deviation of 3.8% and NPS results were comparable to imQuest.CONCLUSIONS: We developed a fully automated, open-source, robust method to quantify CAC on CT scans in a commercially available phantom. Also, the automated algorithm contains image quality assessment for fast comparison of differences in acquisition and reconstruction parameters.

  View details for DOI 10.1002/mp.14912

  View details for PubMedID 33932026

• Emerging methods for the characterization of ischemic heart disease: ultrafast Doppler angiography, micro-CT, photon-counting CT, novel MRI and PET techniques, and artificial intelligence. European radiology experimental Willemink, M. J., Varga-Szemes, A., Schoepf, U. J., Codari, M., Nieman, K., Fleischmann, D., Mastrodicasa, D. 2021; 5 (1): 12

  Abstract

  After an ischemic event, disruptive changes in the healthy myocardium may gradually develop and may ultimately turn into fibrotic scar. While these structural changes have been described by conventional imaging modalities mostly on a macroscopic scale-i.e., late gadolinium enhancement at magnetic resonance imaging (MRI)-in recent years, novel imaging methods have shown the potential to unveil an even more detailed picture of the postischemic myocardial phenomena. These new methods may bring advances in the understanding of ischemic heart disease with potential major changes in the current clinical practice. In this review article, we provide an overview of the emerging methods for the non-invasive characterization of ischemic heart disease, including coronary ultrafast Doppler angiography, photon-counting computed tomography (CT), micro-CT (for preclinical studies), low-field and ultrahigh-field MRI, and 11C-methionine positron emission tomography. In addition, we discuss new opportunities brought by artificial intelligence, while addressing promising future scenarios and the challenges for the application of artificial intelligence in the field of cardiac imaging.

  View details for DOI 10.1186/s41747-021-00207-3

  View details for PubMedID 33763754

• CTA pulmonary artery enlargement in patients with severe aortic stenosis: Prognostic impact after TAVR. Journal of cardiovascular computed tomography Turner, V. L., Jubran, A., Kim, J. B., Maret, E., Moneghetti, K. J., Haddad, F., Amsallem, M., Codari, M., Hinostroza, V., Mastrodicasa, D., Sailer, A. M., Kobayashi, Y., Nishi, T., Yeung, A. C., Watkins, A. C., Lee, A. M., Miller, D. C., Fischbein, M. P., Fearon, W. F., Willemink, M. J., Fleischmann, D. 2021

  Abstract

  BACKGROUND: Identifying high-risk patients who will not derive substantial survival benefit from TAVR remains challenging. Pulmonary hypertension is a known predictor of poor outcome in patients undergoing TAVR and correlates strongly with pulmonary artery (PA) enlargement on CTA. We sought to evaluate whether PA enlargement, measured on pre-procedural computed tomography angiography (CTA), is associated with 1-year mortality in patients undergoing TAVR.METHODS: We retrospectively included 402 patients undergoing TAVR between July 2012 and March 2016. Clinical parameters, including Society of Thoracic Surgeons (STS) score and right ventricular systolic pressure (RVSP) estimated by transthoracic echocardiography were reviewed. PA dimensions were measured on pre-procedural CTAs. Association between PA enlargement and 1-year mortality was analyzed. Kaplan-Meier and Cox proportional hazards regression analyses were performed.RESULTS: The median follow-up time was 433 (interquartiles 339-797) days. A total of 56/402 (14%) patients died within 1 year after TAVR. Main PA area (area-MPA) was independently associated with 1-year mortality (hazard ratio per standard deviation equal to 2.04 [95%-confidence interval (CI) 1.48-2.76], p​<​0.001). Area under the curve (95%-CI) of the clinical multivariable model including STS-score and RVSP increased slightly from 0.67 (0.59-0.75) to 0.72 (0.72-0.89), p​=​0.346 by adding area-MPA. Although the AUC increased, differences were not significant (p​=​0.346). Kaplan-Meier analysis showed that mortality was significantly higher in patients with a pre-procedural non-indexed area-MPA of ≥7.40​cm2 compared to patients with a smaller area-MPA (mortality 23% vs. 9%; p​<​0.001).CONCLUSIONS: Enlargement of MPA on pre-procedural CTA is independently associated with 1-year mortality after TAVR.

  View details for DOI 10.1016/j.jcct.2021.03.004

  View details for PubMedID 33795188

• An international survey on AI in radiology in 1,041 radiologists and radiology residents part 1: fear of replacement, knowledge, and attitude. European radiology Huisman, M., Ranschaert, E., Parker, W., Mastrodicasa, D., Koci, M., Pinto de Santos, D., Coppola, F., Morozov, S., Zins, M., Bohyn, C., Koc, U., Wu, J., Veean, S., Fleischmann, D., Leiner, T., Willemink, M. J. 2021

  Abstract

  OBJECTIVES: Radiologists' perception is likely to influence the adoption of artificial intelligence (AI) into clinical practice. We investigated knowledge and attitude towards AI by radiologists and residents in Europe and beyond.METHODS: Between April and July 2019, a survey on fear of replacement, knowledge, and attitude towards AI was accessible to radiologists and residents. The survey was distributed through several radiological societies, author networks, and social media. Independent predictors of fear of replacement and a positive attitude towards AI were assessed using multivariable logistic regression.RESULTS: The survey was completed by 1,041 respondents from 54 mostly European countries. Most respondents were male (n = 670, 65%), median age was 38 (24-74) years, n = 142 (35%) residents, and n = 471 (45%) worked in an academic center. Basic AI-specific knowledge was associated with fear (adjusted OR 1.56, 95% CI 1.10-2.21, p = 0.01), while intermediate AI-specific knowledge (adjusted OR 0.40, 95% CI 0.20-0.80, p = 0.01) or advanced AI-specific knowledge (adjusted OR 0.43, 95% CI 0.21-0.90, p = 0.03) was inversely associated with fear. A positive attitude towards AI was observed in 48% (n = 501) and was associated with only having heard of AI, intermediate (adjusted OR 11.65, 95% CI 4.25-31.92, p < 0.001), or advanced AI-specific knowledge (adjusted OR 17.65, 95% CI 6.16-50.54, p < 0.001).CONCLUSIONS: Limited AI-specific knowledge levels among radiology residents and radiologists are associated with fear, while intermediate to advanced AI-specific knowledge levels are associated with a positive attitude towards AI. Additional training may therefore improve clinical adoption.KEY POINTS: Forty-eight percent of radiologists and residents have an open and proactive attitude towards artificial intelligence (AI), while 38% fear of replacement by AI. Intermediate and advanced AI-specific knowledge levels may enhance adoption of AI in clinical practice, while rudimentary knowledge levels appear to be inhibitive. AI should be incorporated in radiology training curricula to help facilitate its clinical adoption.

  View details for DOI 10.1007/s00330-021-07781-5

  View details for PubMedID 33744991

• Semi-automatic vessel detection for challenging cases of peripheral arterial disease. Computers in biology and medicine Mistelbauer, G., Morar, A., Schernthaner, R., Strassl, A., Fleischmann, D., Moldoveanu, F., Groller, M. E. 2021; 133: 104344

  Abstract

  OBJECTIVES: Manual or semi-automated segmentation of the lower extremity arterial tree in patients with Peripheral arterial disease (PAD) remains a notoriously difficult and time-consuming task. The complex manifestations of the disease, including discontinuities of the vascular flow channels, the presence of calcified atherosclerotic plaque in close vicinity to adjacent bone, and the presence of metal or other imaging artifacts currently preclude fully automated vessel identification. New machine learning techniques may alleviate this challenge, but require large and reasonably well segmented training data.METHODS: We propose a novel semi-automatic vessel tracking approach for peripheral arteries to facilitate and accelerate the creation of annotated training data by expert cardiovascular radiologists or technologists, while limiting the number of necessary manual interactions, and reducing processing time. After automatically classifying blood vessels, bones, and other tissue, the relevant vessels are tracked and organized in a tree-like structure for further visualization.RESULTS: We conducted a pilot (N = 9) and a clinical study (N = 24) in which we assess the accuracy and required time for our approach to achieve sufficient quality for clinical application, with our current clinically established workflow as the standard of reference. Our approach enabled expert physicians to readily identify all clinically relevant lower extremity arteries, even in problematic cases, with an average sensitivity of 92.9%, and an average specificity and overall accuracy of 99.9%.CONCLUSIONS: Compared to the clinical workflow in our collaborating hospitals (28:40 ± 7:45 [mm:ss]), our approach (17:24 ± 6:44 [mm:ss]) is on average 11:16 [mm:ss] (39%) faster.

  View details for DOI 10.1016/j.compbiomed.2021.104344

  View details for PubMedID 33915360

• Aortic Dissection and Other Acute Aortic Syndromes: Diagnostic Imaging Findings from Acute to Chronic Longitudinal Progression. Radiographics : a review publication of the Radiological Society of North America, Inc Murillo, H., Molvin, L., Chin, A. S., Fleischmann, D. 2021; 41 (2): 425–46

  Abstract

  Acute aortic dissection is the prototype of acute aortic syndromes (AASs), which include intramural hematoma, limited intimal tear, penetrating atherosclerotic ulcer, traumatic or iatrogenic aortic dissection, and leaking or ruptured aortic aneurysm. The manifestation is usually sudden and catastrophic with acutely severe tearing chest or back pain. However, clinical symptoms do not allow distinction between AAS types and other acute pathologic conditions. Diagnostic imaging is essential to rapidly confirm and accurately diagnose the type, magnitude, and complications of AASs. CT fast acquisition of volumetric datasets has become instrumental in diagnosis, surveillance, and intervention planning. Most critical findings affecting initial intervention and prognosis are obtained at CT, including involvement of the ascending aorta, primary intimal tear location, rupture, malperfusion, size and patency of the false lumen, complexity and extent of the dissection, maximum caliber of the aorta, and progression or postintervention complications. Involvement of the ascending aorta-Stanford type A-has the most rapid lethal complications and requires surgical intervention to affect its morbidity and mortality. Lesions not involving the ascending aorta-Stanford type B-have a lesser rate of complications in the acute phase. During the acute to longitudinal progression, various specific and nonspecific imaging findings are encountered, including pleural and pericardial effusions, fluid collections, progression including aortic enlargement, and postoperative changes that can be discerned at CT. A systematic analysis algorithm is proposed for CT of the entire aorta throughout the continuum of AASs into the chronic and posttreated disease state, which synthesizes and communicates salient findings to all care providers. Online supplemental material is available for this article. ©RSNA, 2021.

  View details for DOI 10.1148/rg.2021200138

  View details for PubMedID 33646901

• Aorto-iliac/right leg arterial thrombosis necessitating limb amputation, pulmonary arterial, intracardiac, and ilio-caval venous thrombosis in a 40-year-old with COVID-19. Clinical imaging Madani, M. H., Leung, A. N., Becker, H. C., Chan, F. P., Fleischmann, D. n. 2021; 75: 1–4

  Abstract

  We describe a 40-year-old man with severe COVID-19 requiring mechanical ventilation who developed aorto-bi-iliac arterial, right lower extremity arterial, intracardiac, pulmonary arterial and ilio-caval venous thromboses and required right lower extremity amputation for acute limb ischemia. This unique case illustrates COVID-19-associated thrombotic complications occurring at multiple, different sites in the cardiovascular system of a single infected patient.

  View details for DOI 10.1016/j.clinimag.2020.12.036

  View details for PubMedID 33477081

• Deep Learning-Based 3D Segmentation of True Lumen, False Lumen, and False Lumen Thrombosis in Type-B Aortic Dissection. Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference Wobben, L. D., Codari, M., Mistelbauer, G., Pepe, A., Higashigaito, K., Hahn, L. D., Mastrodicasa, D., Turner, V. L., Hinostroza, V., Baumler, K., Fischbein, M. P., Fleischmann, D., Willemink, M. J. 2021; 2021: 3912-3915

  Abstract

  Patients with initially uncomplicated typeB aortic dissection (uTBAD) remain at high risk for developing late complications. Identification of morphologic features for improving risk stratification of these patients requires automated segmentation of computed tomography angiography (CTA) images. We developed three segmentation models utilizing a 3D residual U-Net for segmentation of the true lumen (TL), false lumen (FL), and false lumen thrombosis (FLT). Model 1 segments all labels at once, whereas model 2 segments them sequentially. Best results for TL and FL segmentation were achieved by model 2, with median (interquartiles) Dice similarity coefficients (DSC) of 0.85 (0.77-0.88) and 0.84 (0.82-0.87), respectively. For FLT segmentation, model 1 was superior to model 2, with median (interquartiles) DSCs of 0.63 (0.40-0.78). To purely test the performance of the network to segment FLT, a third model segmented FLT starting from the manually segmented FL, resulting in median (interquartiles) DSCs of 0.99 (0.98-0.99) and 0.85 (0.73-0.94) for patent FL and FLT, respectively. While the ambiguous appearance of FLT on imaging remains a significant limitation for accurate segmentation, our pipeline has the potential to help in segmentation of aortic lumina and thrombosis in uTBAD patients.Clinical relevance- Most predictors of aortic dissection (AD) degeneration are identified through anatomical modeling, which is currently prohibitive in clinical settings due to the timeintense human interaction. False lumen thrombosis, which often develops in patients with type B AD, has proven to show significant prognostic value for predicting late adverse events. Our automated segmentation algorithm offers the potential of personalized treatment for AD patients, leading to an increase in long-term survival.

  View details for DOI 10.1109/EMBC46164.2021.9631067

  View details for PubMedID 34892087

• A discrete approach for modeling degraded elastic fibers in aortic dissection COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING Rolf-Pissarczyk, M., Li, K., Fleischmann, D., Holzapfel, G. A. 2021; 373

  View details for DOI 10.1016/j.cma.2020.113511

  View details for Web of Science ID 000600287300006

• Extravasation Volume at Computed Tomography Angiography Correlates With Bleeding Rate and Prognosis in Patients With Overt Gastrointestinal Bleeding. Investigative radiology Tse, J. R., Shen, J. n., Shah, R. n., Fleischmann, D. n., Kamaya, A. n. 2021

  Abstract

  Despite the identification of active extravasation on computed tomography angiography (CTA) in patients with overt gastrointestinal bleeding (GIB), a large proportion do not have active bleeding or require hemostatic therapy at endoscopy, catheter angiography, or surgery. The objective of our proof-of-concept study was to improve triage of patients with GIB by correlating extravasation volume of first-pass CTA with bleeding rate and clinical outcomes.All patients who presented with overt GIB and active extravasation on CTA from January 2014 to July 2019 were reviewed in this retrospective, institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study. Extravasation volume was assessed using 3-dimensional software and correlated with hemostatic therapy (primary endpoint) and with intraprocedural bleeding, blood transfusions, and mortality as secondary endpoints using logistic regression models (P < 0.0125 indicating statistical significance). Odds ratios were used to determine the effect size of a threshold extravasation volume. Quantitative data (extravasation volume, aorta attenuation, extravasation attenuation and time) were input into a mathematical model to calculate bleeding rate.Fifty consecutive patients including 6 (12%) upper, 18 (36%) small bowel, and 26 (52%) lower GIB met inclusion criteria. Forty-two underwent catheter angiography, endoscopy, or surgery; 16 had intraprocedural active bleeding, and 24 required hemostatic therapy. Higher extravasation volumes correlated with hemostatic therapy (P = 0.007), intraprocedural active bleeding (P = 0.003), and massive transfusion (P = 0.0001), but not mortality (P = 0.936). Using a threshold volume of 0.80 mL or greater, the odds ratio of hemostatic therapy was 8.1 (95% confidence interval, 2.1-26), active bleeding was 11.8 (2.6-45), and massive transfusion was 18 (2.3-65). With mathematical modeling, extravasation volume had a direct and linear relationship with bleeding rate, and the lowest calculated detectable bleeding rate with CTA was less than 0.1 mL/min.Larger extravasation volumes correlate with higher bleeding rates and may identify patients who require hemostatic therapy, have intraprocedural bleeding, and require blood transfusions. Current CTAs can detect bleeding rates less than 0.1 mL/min.

  View details for DOI 10.1097/RLI.0000000000000753

  View details for PubMedID 33449577

• Spectral photon-counting CT in cardiovascular imaging. Journal of cardiovascular computed tomography Sandfort, V., Persson, M., Pourmorteza, A., Noel, P. B., Fleischmann, D., Willemink, M. J. 2020

  Abstract

  Photon-counting computed tomography (PCCT) is an emerging technology promising to substantially improve cardiovascular imaging. Recent engineering and manufacturing advances by several vendors are expected to imminently launch this new technology into clinical reality. Photon-counting detectors (PCDs) have multiple potential advantages over conventional energy integrating detectors (EIDs) such as the absence of electronic noise, multi-energy capability, and increased spatial resolution. These developments will have different timescales for implementation and will affect different clinical scopes. We describe the technical aspects of PCCT, explain the current developments, and finally discuss potential advantages of PCCT in cardiovascular imaging.

  View details for DOI 10.1016/j.jcct.2020.12.005

  View details for PubMedID 33358186

• Repair of extra-anatomic bypass graft structural degeneration and pseudoaneurysm with endovascular stent-graft relining JTCVS TECHNIQUES Stephens, E. H., Fleischmann, D., Starr, A., Miller, D. 2020; 3: 259-262

  View details for DOI 10.1016/j.xjtc.2020.04.030

  View details for Web of Science ID 000655698900098

• Repair of extra-anatomic bypass graft structural degeneration and pseudoaneurysm with endovascular stent-graft relining. JTCVS techniques Stephens, E. H., Fleischmann, D., Starr, A., Miller, D. C. 2020; 3: 259-262

  View details for DOI 10.1016/j.xjtc.2020.04.030

  View details for PubMedID 34317893

  View details for PubMedCentralID PMC8303061

• Delivery of hepatocyte growth factor mRNA from nanofibrillar scaffolds in a pig model of peripheral arterial disease. Regenerative medicine S Zaitseva, T., Yang, G., Dionyssiou, D., Zamani, M., Sawamura, S., Yakubov, E., Ferguson, J., Hallett, R. L., Fleischmann, D., Paukshto, M. V., Huang, N. F. 2020

  Abstract

  Background: Chemical modification of mRNA (mmRNA) substantially improves their stability and translational efficiency within cells. Nanofibrillar collagen scaffolds were previously shown to enable the spatially localized delivery and temporally controlled release of mmRNA encoding HGF both in vitro and in vivo. Materials &methods: Herein we developed an improved slow-releasing HGF mmRNA scaffold and tested its therapeutic efficacy in a porcine model of peripheral arterial disease. Results & conclusion: The HGF mmRNA wasreleased from scaffolds in a temporally controlled fashion in vitro with preserved transfection activity. The mmRNA scaffolds improved vascular regeneration when sutured to the ligated porcine femoral artery. These studies validate the therapeutic potential of HGF mmRNA delivery from nanofibrillar scaffolds for treatment of peripheral arterial disease.

  View details for DOI 10.2217/rme-2020-0023

  View details for PubMedID 32772903

• Carotid plaque imaging and the risk of atherosclerotic cardiovascular disease. Cardiovascular diagnosis and therapy Zhu, G., Hom, J., Li, Y., Jiang, B., Rodriguez, F., Fleischmann, D., Saloner, D., Porcu, M., Zhang, Y., Saba, L., Wintermark, M. 2020; 10 (4): 1048-1067

  Abstract

  Carotid artery plaque is a measure of atherosclerosis and is associated with future risk of atherosclerotic cardiovascular disease (ASCVD), which encompasses coronary, cerebrovascular, and peripheral arterial diseases. With advanced imaging techniques, computerized tomography (CT) and magnetic resonance imaging (MRI) have shown their potential superiority to routine ultrasound to detect features of carotid plaque vulnerability, such as intraplaque hemorrhage (IPH), lipid-rich necrotic core (LRNC), fibrous cap (FC), and calcification. The correlation between imaging features and histological changes of carotid plaques has been investigated. Imaging of carotid features has been used to predict the risk of cardiovascular events. Other techniques such as nuclear imaging and intra-vascular ultrasound (IVUS) have also been proposed to better understand the vulnerable carotid plaque features. In this article, we review the studies of imaging specific carotid plaque components and their correlation with risk scores.

  View details for DOI 10.21037/cdt.2020.03.10

  View details for PubMedID 32968660

  View details for PubMedCentralID PMC7487384

• Dramatic Case of Paradoxical Embolism. Radiology. Cardiothoracic imaging Pogatchnik, B. P., Fleischmann, D. 2020; 2 (4): e200360

  View details for DOI 10.1148/ryct.2020200360

  View details for PubMedID 33778615

• The Project Baseline Health Study: a step towards a broader mission to map human health. NPJ digital medicine Arges, K., Assimes, T., Bajaj, V., Balu, S., Bashir, M. R., Beskow, L., Blanco, R., Califf, R., Campbell, P., Carin, L., Christian, V., Cousins, S., Das, M., Dockery, M., Douglas, P. S., Dunham, A., Eckstrand, J., Fleischmann, D., Ford, E., Fraulo, E., French, J., Gambhir, S. S., Ginsburg, G. S., Green, R. C., Haddad, F., Hernandez, A., Hernandez, J., Huang, E. S., Jaffe, G., King, D., Koweek, L. H., Langlotz, C., Liao, Y. J., Mahaffey, K. W., Marcom, K., Marks, W. J., Maron, D., McCabe, R., McCall, S., McCue, R., Mega, J., Miller, D., Muhlbaier, L. H., Munshi, R., Newby, L. K., Pak-Harvey, E., Patrick-Lake, B., Pencina, M., Peterson, E. D., Rodriguez, F., Shore, S., Shah, S., Shipes, S., Sledge, G., Spielman, S., Spitler, R., Schaack, T., Swamy, G., Willemink, M. J., Wong, C. A. 2020; 3 (1): 84

  Abstract

  The Project Baseline Health Study (PBHS) was launched to map human health through a comprehensive understanding of both the health of an individual and how it relates to the broader population. The study will contribute to the creation of a biomedical information system that accounts for the highly complex interplay of biological, behavioral, environmental, and social systems. The PBHS is a prospective, multicenter, longitudinal cohort study that aims to enroll thousands of participants with diverse backgrounds who are representative of the entire health spectrum. Enrolled participants will be evaluated serially using clinical, molecular, imaging, sensor, self-reported, behavioral, psychological, environmental, and other health-related measurements. An initial deeply phenotyped cohort will inform the development of a large, expanded virtual cohort. The PBHS will contribute to precision health and medicine by integrating state of the art testing, longitudinal monitoring and participant engagement, and by contributing to the development of an improved platform for data sharing and analysis.

  View details for DOI 10.1038/s41746-020-0290-y

  View details for PubMedID 33597683

• The Project Baseline Health Study: a step towards a broader mission to map human health NPJ DIGITAL MEDICINE Arges, K., Assimes, T., Bajaj, V., Balu, S., Bashir, M. R., Beskow, L., Blanco, R., Califf, R., Campbell, P., Carin, L., Christian, V., Cousins, S., Das, M., Dockery, M., Douglas, P. S., Dunham, A., Eckstrand, J., Fleischmann, D., Ford, E., Fraulo, E., French, J., Gambhir, S. S., Ginsburg, G. S., Green, R. C., Haddad, F., Hernandez, A., Hernandez, J., Huang, E. S., Jaffe, G., King, D., Koweek, L. H., Langlotz, C., Liao, Y. J., Mahaffey, K. W., Marcom, K., Marks, W. J., Maron, D., McCabe, R., McCall, S., McCue, R., Mega, J., Miller, D., Muhlbaier, L. H., Munshi, R., Newby, L., Pak-Harvey, E., Patrick-Lake, B., Pencina, M., Peterson, E. D., Rodriguez, F., Shore, S., Shah, S., Shipes, S., Sledge, G., Spielman, S., Spitler, R., Schaack, T., Swamy, G., Willemink, M. J., Wong, C. A. 2020; 3 (1): 84

  Abstract

  The Project Baseline Health Study (PBHS) was launched to map human health through a comprehensive understanding of both the health of an individual and how it relates to the broader population. The study will contribute to the creation of a biomedical information system that accounts for the highly complex interplay of biological, behavioral, environmental, and social systems. The PBHS is a prospective, multicenter, longitudinal cohort study that aims to enroll thousands of participants with diverse backgrounds who are representative of the entire health spectrum. Enrolled participants will be evaluated serially using clinical, molecular, imaging, sensor, self-reported, behavioral, psychological, environmental, and other health-related measurements. An initial deeply phenotyped cohort will inform the development of a large, expanded virtual cohort. The PBHS will contribute to precision health and medicine by integrating state of the art testing, longitudinal monitoring and participant engagement, and by contributing to the development of an improved platform for data sharing and analysis.

  View details for DOI 10.1038/s41746-020-0290-y

  View details for Web of Science ID 000538242900001

  View details for PubMedID 32550652

  View details for PubMedCentralID PMC7275087

• Impact of right ventricular volumes on the outcomes of TAVR: a volumetric analysis of preprocedural computed tomography EUROINTERVENTION Rozenbaum, Z., Maret, E., Lax, L., Shmilovich, H., Finkelstein, A., Steinvil, A., Halkin, A., Banai, S., Cohen, D., Topilsky, Y., Berliner, S., Fleischmann, D., Aviram, G. 2020; 16 (2): E121-+

  Abstract

  The aim of this study was to assess the prognostic implications of increased right ventricle volume index (RVVI) using cardiac-gated computed tomography angiography (CCTA) data among patients undergoing transcatheter valve replacement (TAVR).CCTA of 323 patients who underwent TAVR at Stanford University Medical Center (CA, USA) and Tel Aviv Medical Center (Israel) between 2013 and 2016 was analysed by an automatic four-chamber volumetric software and grouped into quartiles according to RVVI. Higher one-year mortality rates were noted for the upper quartiles - 5%, 4.9%, 8.6%, and 16% (p=0.039), in Q1 <59 ml/m2, Q2 59-69 ml/m2, Q3 69-86 ml/m2, and Q4 >86 ml/m2, respectively. However, the differences were not significant after propensity score adjustments. Sub-analyses of Q1 demonstrated an escalating risk for one-year mortality in concordance to RVVI: HR 2.28, HR 2.76, and HR 4.7, for the upper 25th, 15th, and 5th percentiles, respectively (p<0.05 for all comparisons). After propensity score adjustments for clinical and echocardiographic characteristics, only the upper 5th percentiles (RVVI >120 ml/m2) retained statistical significance (HR 2.82, 95% CI: 1.02-7.78, p=0.045). Notably, 68.7% of patients from this group were considered low-intermediate risk for surgery.Cardiac volumetric data by CCTA performed for procedural planning may help to predict outcome in patients undergoing TAVR.

  View details for DOI 10.4244/EIJ-D-19-00651

  View details for Web of Science ID 000547855500003

  View details for PubMedID 31566570

• CT-based True- and False-Lumen Segmentation in Type B Aortic Dissection Using Machine Learning. Radiology. Cardiothoracic imaging Hahn, L. D., Mistelbauer, G., Higashigaito, K., Koci, M., Willemink, M. J., Sailer, A. M., Fischbein, M., Fleischmann, D. 2020; 2 (3): e190179

  Abstract

  Purpose: To develop a segmentation pipeline for segmentation of aortic dissection CT angiograms into true and false lumina on multiplanar reformations (MPRs) perpendicular to the aortic centerline and derive quantitative morphologic features, specifically aortic diameter and true- or false-lumen cross-sectional area.Materials and Methods: An automated segmentation pipeline including two convolutional neural network (CNN) segmentation algorithms was developed. The algorithm derives the aortic centerline, generates MPRs orthogonal to the centerline, and segments the true and false lumina. A total of 153 CT angiograms obtained from 45 retrospectively identified patients (mean age, 50 years; range, 22-79 years) were used to train (n = 103), validate (n = 22), and test (n = 28) the CNN pipeline. Accuracy was evaluated by using the Dice similarity coefficient (DSC). Segmentations were then used to derive the maximal diameter of test-set patients and cross-sectional area profiles of the true and false lumina.Results: The segmentation pipeline yielded a mean DSC of 0.873 ± 0.056 for the true lumina and 0.894 ± 0.040 for the false lumina of test-set cases. Automated maximal diameter measurements correlated well with manual measurements (R 2 = 0.95). Profiles of cross-sectional diameter, true-lumen area, and false-lumen area over several follow-up examinations were derived.Conclusion: A segmentation pipeline was used to accurately identify true and false lumina on CT angiograms of aortic dissection. These segmentations can be used to obtain diameter and other morphologic parameters for surveillance and risk stratification.Supplemental material is available for this article.© RSNA, 2020.

  View details for DOI 10.1148/ryct.2020190179

  View details for PubMedID 33778582

• Deep Flow-Net for EPI Distortion Estimation. NeuroImage Zahneisen, B., Baeumler, K., Zaharchuk, G., Fleischmann, D., Zeineh, M. 2020: 116886

  Abstract

  INTRODUCTION: Geometric distortions along the phase encoding direction caused by off-resonant spins are a major issue in EPI based functional and diffusion imaging. The widely used blip up/down approach estimates the underlying distortion field from a pair of images with inverted phase encoding direction. Typically, iterative methods are used to find a solution to the ill-posed problem of finding the displacement field that maps up/down acquisitions onto each other. Here, we explore the use of a deep convolutional network to estimate the displacement map from a pair of input images.METHODS: We trained a deep convolutional U-net architecture that was previously used to estimate optic flow between moving images to learn to predict the distortion map from an input pair of distorted EPI acquisitions. During the training step, the network minimizes a loss function (similarity metric) that is calculated from corrected input image pairs. This approach does not require the explicit knowledge of the ground truth distortion map, which is difficult to get for real life data.RESULTS: We used data from a total of Ntrain=22 healthy subjects to train our network. A separate dataset of Ntest=12 patients including some with abnormal findings and unseen acquisition modes, e.g. LR-encoding, coronal orientation) was reserved for testing and evaluation purposes. We compared our results to FSL's topup function with default parameters that served as the gold standard. We found that our approach results in a correction accuracy that is virtually identical to the optimum found by an iterative search, but with reduced computational time.CONCLUSION: By using a deep convolutional network, we can reduce the processing time to a few seconds per volume, which is significantly faster than iterative approaches like FSL's topup which takes around 10min on the same machine (but using only 1 CPU). This facilitates the use of a blip up/down scheme for all diffusion-weighted acquisitions and potential real-time EPI distortion correction without sacrificing accuracy.

  View details for DOI 10.1016/j.neuroimage.2020.116886

  View details for PubMedID 32389728

• 3D Printed Models of Brain and Intracranial Electrodes for Epilepsy Education and Surgical Planning Ardestani, P., Gifford, K., Bogart, K., Walters, S., Zeineh, M., Fleischmann, D., Razavi, B. LIPPINCOTT WILLIAMS & WILKINS. 2020

  View details for Web of Science ID 000536058005042

• Preparing Medical Imaging Data for Machine Learning. Radiology Willemink, M. J., Koszek, W. A., Hardell, C., Wu, J., Fleischmann, D., Harvey, H., Folio, L. R., Summers, R. M., Rubin, D. L., Lungren, M. P. 2020: 192224

  Abstract

  Artificial intelligence (AI) continues to garner substantial interest in medical imaging. The potential applications are vast and include the entirety of the medical imaging life cycle from image creation to diagnosis to outcome prediction. The chief obstacles to development and clinical implementation of AI algorithms include availability of sufficiently large, curated, and representative training data that includes expert labeling (eg, annotations). Current supervised AI methods require a curation process for data to optimally train, validate, and test algorithms. Currently, most research groups and industry have limited data access based on small sample sizes from small geographic areas. In addition, the preparation of data is a costly and time-intensive process, the results of which are algorithms with limited utility and poor generalization. In this article, the authors describe fundamental steps for preparing medical imaging data in AI algorithm development, explain current limitations to data curation, and explore new approaches to address the problem of data availability.

  View details for DOI 10.1148/radiol.2020192224

  View details for PubMedID 32068507

• Accuracy of a novel stress echocardiography pattern for myocardial bridging in patients with angina and no obstructive coronary artery disease - A retrospective and prospective cohort study. International journal of cardiology Pargaonkar, V. S., Rogers, I. S., Su, J., Forsdahl, S. H., Kameda, R., Schreiber, D., Chan, F. P., Becker, H., Fleischmann, D., Tremmel, J. A., Schnittger, I. 2020

  Abstract

  BACKGROUND: Myocardial bridge (MB) may cause angina in patients with no obstructive coronary artery disease (CAD). We previously reported a novel stress echocardiography (SE) pattern of focal septal buckling with apical sparing in the end-systolic to early-diastolic phase that is associated with the presence of an MB. We evaluated the diagnostic accuracy of this pattern, and prospectively validated our results.METHODS: The retrospective cohort included 158 patients with angina who underwent both SE and coronary CT angiography (CCTA). The validation cohort included 37 patients who underwent CCTA in the emergency department for angina, and prospectively underwent SE. CCTA was used as a reference standard for the presence/absence of an MB, and also confirmed no obstructive CAD.RESULTS: In the retrospective cohort, an MB was present in 107 (67.7%). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 91.6%, 70.6%, 86.7% and 80%, respectively. On logistic regression, focal septal buckling and Duke treadmill score were associated with an MB. In the validation cohort, an MB was present in 31 (84%). The sensitivity, specificity PPV and NPV were 90.3%, 83.3%, 96.5% and 62.5%, respectively. On logistic regression, focal septal buckling was associated with an MB.CONCLUSION: Presence of focal septal buckling with apical sparing on SE is an accurate predictor of an MB in patients with angina and no obstructive CAD. This pattern can reliably be used to screen patients who may benefit from advanced non-invasive/invasive testing for an MB as a cause of their angina.

  View details for DOI 10.1016/j.ijcard.2020.02.006

  View details for PubMedID 32145938

• Machine learning for endoleak detection after endovascular aortic repair. Scientific reports Talebi, S. n., Madani, M. H., Madani, A. n., Chien, A. n., Shen, J. n., Mastrodicasa, D. n., Fleischmann, D. n., Chan, F. P., Mofrad, M. R. 2020; 10 (1): 18343

  Abstract

  Diagnosis of endoleak following endovascular aortic repair (EVAR) relies on manual review of multi-slice CT angiography (CTA) by physicians which is a tedious and time-consuming process that is susceptible to error. We evaluate the use of a deep neural network for the detection of endoleak on CTA for post-EVAR patients using a novel data efficient training approach. 50 CTAs and 20 CTAs with and without endoleak respectively were identified based on gold standard interpretation by a cardiovascular subspecialty radiologist. The Endoleak Augmentor, a custom designed augmentation method, provided robust training for the machine learning (ML) model. Predicted segmentation maps underwent post-processing to determine the presence of endoleak. The model was tested against 3 blinded general radiologists and 1 blinded subspecialist using a held-out subset (10 positive endoleak CTAs, 10 control CTAs). Model accuracy, precision and recall for endoleak diagnosis were 95%, 90% and 100% relative to reference subspecialist interpretation (AUC = 0.99). Accuracy, precision and recall was 70/70/70% for generalist1, 50/50/90% for generalist2, and 90/83/100% for generalist3. The blinded subspecialist had concordant interpretations for all test cases compared with the reference. In conclusion, our ML-based approach has similar performance for endoleak diagnosis relative to subspecialists and superior performance compared with generalists.

  View details for DOI 10.1038/s41598-020-74936-7

  View details for PubMedID 33110113

• The utility of three-dimensional models in complex microsurgical reconstruction. Archives of plastic surgery Ogunleye, A. A., Deptula, P. L., Inchauste, S. M., Zelones, J. T., Walters, S. n., Gifford, K. n., LeCastillo, C. n., Napel, S. n., Fleischmann, D. n., Nguyen, D. H. 2020; 47 (5): 428–34

  Abstract

  Three-dimensional (3D) model printing improves visualization of anatomical structures in space compared to two-dimensional (2D) data and creates an exact model of the surgical site that can be used for reference during surgery. There is limited evidence on the effects of using 3D models in microsurgical reconstruction on improving clinical outcomes.A retrospective review of patients undergoing reconstructive breast microsurgery procedures from 2017 to 2019 who received computed tomography angiography (CTA) scans only or with 3D models for preoperative surgical planning were performed. Preoperative decision-making to undergo a deep inferior epigastric perforator (DIEP) versus muscle-sparing transverse rectus abdominis myocutaneous (MS-TRAM) flap, as well as whether the decision changed during flap harvest and postoperative complications were tracked based on the preoperative imaging used. In addition, we describe three example cases showing direct application of 3D mold as an accurate model to guide intraoperative dissection in complex microsurgical reconstruction.Fifty-eight abdominal-based breast free-flaps performed using conventional CTA were compared with a matched cohort of 58 breast free-flaps performed with 3D model print. There was no flap loss in either group. There was a significant reduction in flap harvest time with use of 3D model (CTA vs. 3D, 117.7±14.2 minutes vs. 109.8±11.6 minutes; P=0.001). In addition, there was no change in preoperative decision on type of flap harvested in all cases in 3D print group (0%), compared with 24.1% change in conventional CTA group.Use of 3D print model improves accuracy of preoperative planning and reduces flap harvest time with similar postoperative complications in complex microsurgical reconstruction.

  View details for DOI 10.5999/aps.2020.00829

  View details for PubMedID 32971594

• Coronary Computed Tomography Angiography in Diagnosing Obstructive Coronary Artery Disease in Patients with Advanced Chronic Kidney Disease: A Systematic Review and Meta-Analysis. Cardiorenal medicine Cheng, X. S., Mohanty, S. n., Turner, V. n., Mastrodicasa, D. n., Winther, S. n., Fleischmann, D. n., Tan, J. C., Fearon, W. F. 2020: 1–8

  Abstract

  Coronary computed tomography angiography (CCTA) is emerging as an important noninvasive testing modality for coronary angiography. The performance characteristic of CCTA in patients with advanced kidney disease is unknown.We performed a systematic review and meta-analysis of studies specifically investigating the sensitivity and specificity of CCTA compared to coronary angiogram as a reference standard in patients with advanced kidney disease, defined as dialysis dependence or nearing kidney transplantation. Two independent investigators assessed studies for inclusion/exclusion, quality, and characteristics, while a third investigator adjudicated.We identified 4 studies including a total of 217 patients, of whom 159 were dialysis dependent. Three of the 4 studies had a high risk of bias in patient selection and study flow, while 1 study rated low in all areas of bias. The studies were heterogeneous in their patient selection and CCTA protocol but consistent in their definition of obstructive coronary artery disease. The pooled sensitivity and specificity for CCTA were 0.96 (0.87-0.99) and 0.66 (0.57-0.74), respectively. When we restricted the analysis to dialysis-dependent patients, the pooled sensitivity and specificity for CCTA were 0.99 (0.74-1.00) and 0.67 (0.49-0.82), respectively.Based on limited data, CCTA appears to have comparable sensitivity but lower specificity relative to the non-kidney disease population.

  View details for DOI 10.1159/000510402

  View details for PubMedID 33321489

• Computed Tomographic Angiography-Based Fractional Flow Reserve Compared With Catheter-Based Dobutamine-Stress Diastolic Fractional Flow Reserve in Symptomatic Patients With a Myocardial Bridge and No Obstructive Coronary Artery Disease. Circulation. Cardiovascular imaging Jubran, A. n., Schnittger, I. n., Tremmel, J. n., Pargaonkar, V. n., Rogers, I. n., Becker, H. C., Yang, S. n., Mastrodicasa, D. n., Willemink, M. n., Fleischmann, D. n., Nieman, K. n. 2020; 13 (2): e009576

  View details for DOI 10.1161/CIRCIMAGING.119.009576

  View details for PubMedID 32069114

• Coronary artery calcium: A technical argument for a new scoring method JOURNAL OF CARDIOVASCULAR COMPUTED TOMOGRAPHY Willemink, M. J., van der Werf, N. R., Nieman, K., Greuter, M. W., Koweek, L. M., Fleischmann, D. 2019; 13 (6): 347–52

  View details for DOI 10.1016/j.jcct.2018.10.014

  View details for Web of Science ID 000502828000012

• Carotid Artery Imaging Is More Strongly Associated With the 10-Year Atherosclerotic Cardiovascular Disease Score Than Coronary Artery Imaging. Journal of computer assisted tomography Li, Y., Zhu, G., Ding, V., Jiang, B., Boothroyd, D., Rodriguez, F., Fleischmann, D., Desai, M., Saloner, D., Saba, L., Hom, J., Wintermark, M. 2019; 43 (5): 679–85

  Abstract

  PURPOSE: The aim of this study was to compare coronary and carotid artery imaging and determine which one shows the strongest association with atherosclerotic cardiovascular disease (ASCVD) score.PATIENTS AND METHODS: Two separate series patients who underwent either coronary computed tomography angiography (CTA) or carotid CTA were included. We recorded the ASCVD scores and assessed the CTA imaging. Two thirds were used to build predictive models, and the remaining one third generated predicted ASCVD scores. The Bland-Altman analysis analyzed the concordance.RESULTS: A total of 110 patients were included in each group. There was no significant difference between clinical characteristics. Three imaging variables were included in the carotid model. Two coronary models (presence of calcium or Agatston score) were created. The bias between true and predicted ASCVD scores was 0.37 ± 5.72% on the carotid model, and 2.07 ± 7.18% and 2.47 ± 7.82% on coronary artery models, respectively.CONCLUSIONS: Both carotid and coronary artery imaging features can predict ASCVD score. The carotid artery was more associated to the ASCVD score than the coronary artery.

  View details for DOI 10.1097/RCT.0000000000000920

  View details for PubMedID 31609291

• Feasibility and utility of dual-energy chest CTA for preoperative planning in pediatric pulmonary artery reconstruction INTERNATIONAL JOURNAL OF CARDIOVASCULAR IMAGING Zucker, E. J., Kino, A., Schmiedeskamp, H., Hinostroza, V., Fleischmann, D., Chan, F. P. 2019; 35 (8): 1473–81

  View details for DOI 10.1007/s10554-019-01602-z

  View details for Web of Science ID 000478103100009

• Popup-Plots: Warping Temporal Data Visualization IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS Schmidt, J., Fleischmann, D., Preim, B., Braendle, N., Mistelbauer, G. 2019; 25 (7): 2443–57

  Abstract

  Temporal data visualization is used to analyze dependent variables that vary over time, with time being an independent variable. Visualizing temporal data is inherently difficult, due to the many aspects that need to be communicated to the users (e.g., time and variable changes). This is an important topic in visualization, and a wide range of visualization techniques dealing with different tasks have already been designed. In this paper we propose popup-plots, a novel concept where the common interaction of 3D rotation is used to navigate through the data. This allows the users to view the data from different perspectives without having to learn and adapt to new interaction concepts. Popup-plots are therefore a novel method for visualizing and interacting with dependent variables over time. We extend 2D plots with the temporal information by bending the space according to the time. The bending is calculated based on a spherical coordinates approach, which is continuously influenced by the viewing direction towards the plot. Hence, the plot can be viewed from various angles with seamless transitions in between, offering the possibility to analyze different aspects of the represented data. As the current viewing direction is inherently depicted by the shape of the data, the users are able to deduce which part of the data is currently viewed. The temporal information is encoded into the visualization itself, resembling annual rings of a tree. We demonstrate our method by applying it to data from two different domains, comprising measurements at spatial positions over time, and we also evaluated the usability of our solution.

  View details for DOI 10.1109/TVCG.2018.2841385

  View details for Web of Science ID 000469838700009

  View details for PubMedID 29993580

• Cardiopulmonary-induced deformations of the thoracic aorta following thoracic endovascular aortic repair VASCULAR Suh, G., Ullery, B. W., Lee, J. T., Dake, M. D., Fleischmann, D., Cheng, C. 2019; 27 (2): 181–89

  View details for DOI 10.1177/1708538118811204

  View details for Web of Science ID 000462084800009

• Assessing the Relationship between Atherosclerotic Cardiovascular Disease Risk Score and Carotid Artery Imaging Findings JOURNAL OF NEUROIMAGING Li, Y., Zhu, G., Ding, V., Huang, Y., Jiang, B., Ball, R. L., Rodriguez, F., Fleischmann, D., Desai, M., Saloner, D., Saba, L., Hom, J., Wintermark, M. 2019; 29 (1): 119–25

  View details for DOI 10.1111/jon.12573

  View details for Web of Science ID 000454959000014

• Incremental Value of Aortomitral Continuity Calcification for Risk Assessment after Transcatheter Aortic Valve Replacement. Radiology. Cardiothoracic imaging Willemink, M. J., Maret, E. n., Moneghetti, K. J., Kim, J. B., Haddad, F. n., Kobayashi, Y. n., Nishi, T. n., Nieman, K. n., Cauwenberghs, N. n., Kuznetsova, T. n., Higashigaito, K. n., Sailer, A. M., Yeung, A. C., Lee, A. M., Miller, D. C., Fischbein, M. n., Fearon, W. F., Fleischmann, D. n. 2019; 1 (5): e190067

  Abstract

  To investigate the association of aortomitral continuity calcification (AMCC) with all-cause mortality, postprocedural paravalvular leak (PVL), and prolonged hospital stay in patients undergoing transcatheter aortic valve replacement (TAVR).The authors retrospectively evaluated 329 patients who underwent TAVR between March 2013 and March 2016. AMCC, aortic valve calcification (AVC), and coronary artery calcification (CAC) were quantified by using preprocedural CT. Pre-procedural Society of Thoracic Surgeons (STS) score was recorded. Associations between baseline AMCC, AVC, and CAC and 1-year mortality, PVL, and hospital stay longer than 7 days were analyzed.The median follow-up was 415 days (interquartiles, 344-727 days). After 1 year, 46 of the 329 patients (14%) died and 52 (16%) were hospitalized for more than 7 days. Of the 326 patients who underwent postprocedural echocardiography, 147 (45%) had postprocedural PVL. The CAC score (hazard ratio: 1.11 per 500 points) and AMCC mass (hazard ratio: 1.13 per 500 mg) were associated with 1-year mortality. AVC mass (odds ratio: 1.93 per 100 mg) was associated with postprocedural PVL. Only the STS score was associated with prolonged hospital stay (odds ratio: 1.19 per point).AMCC is associated with mortality within 1 year after TAVR and substantially improves individual risk classification when added to a model consisting of STS score and AVC mass only.Supplemental material is available for this article.© RSNA, 2019See also the commentary by Brown and Leipsic in this issue.

  View details for DOI 10.1148/ryct.2019190067

  View details for PubMedID 33778530

  View details for PubMedCentralID PMC7977784

• Feasibility and utility of dual-energy chest CTA for preoperative planning in pediatric pulmonary artery reconstruction. The international journal of cardiovascular imaging Zucker, E. J., Kino, A. n., Schmiedeskamp, H. n., Hinostroza, V. n., Fleischmann, D. n., Chan, F. P. 2019

  Abstract

  The purpose of this study was to assess in pediatric pulmonary artery (PA) reconstruction candidates the feasibility and added utility of preoperative chest computed tomography angiography (CTA) using dual-energy technique, from which perfused blood volume (PBV)/iodine maps can be generated as a surrogate of pulmonary perfusion. Pediatric PA reconstruction patients were prospectively recruited for a new dose-neutral dual-energy CTA protocol. For each case, the severity of anatomic PA obstruction was graded by two pediatric cardiovascular radiologists in consensus using a modified Qanadli index. PBV maps were qualitatively reviewed and auto-segmented using Siemens syngo.via software. Associations between Qanadli scores and PBV were assessed with Spearman correlation (r) and ROC analysis. Effective radiation doses were estimated from dose-length product and ICRP 103 k-factors, using cubic Hermite spline interpolation. 19 patients were recruited with mean (SD) age of 6.0 (5.1), 11 (57.9%) female, 11 (73.7%) anesthetized. Higher QS correlated with lower PBV, both on a whole lung (r =  - 0.54, p < 0.001) and lobar (r =  - 0.50, p < 0.001) basis. The lung with lowest absolute PBV was predictive of the lung with highest Qanadli score, with AUC of 0.70 (95% CI 0.47-0.93). Qualitatively, PBV maps were heterogeneous, corresponding to multifocal PA stenoses, with decreased iodine content in areas of most severe obstruction. In conclusion, dual-energy chest CTA is feasible for pediatric PA reconstruction candidates. PBV maps show deficits in regions of more severe anatomic obstruction and may serve as a novel biomarker in this population.

  View details for PubMedID 31016501

• Defining genotype-phenotype relationships in patients with hypertrophic cardiomyopathy using cardiovascular magnetic resonance imaging. PloS one Miller, R. J., Heidary, S. n., Pavlovic, A. n., Schlachter, A. n., Dash, R. n., Fleischmann, D. n., Ashley, E. A., Wheeler, M. T., Yang, P. C. 2019; 14 (6): e0217612

  Abstract

  HCM is the most common inherited cardiomyopathy. Historically, there has been poor correlation between genotype and phenotype. However, CMR has the potential to more accurately assess disease phenotype. We characterized phenotype with CMR in a cohort of patients with confirmed HCM and high prevalence of genetic testing.Patients with a diagnosis of HCM, who had undergone contrast-enhanced CMR were identified. Left ventricular mass index (LVMI) and volumes were measured from steady-state free precession sequences. Late gadolinium enhancement (LGE) was quantified using the full width, half maximum method. All patients were prospectively followed for the development of septal reduction therapy, arrhythmia or death.We included 273 patients, mean age 51.2 ± 15.5, 62.9% male. Of those patients 202 (74.0%) underwent genetic testing with 90 pathogenic, likely pathogenic, or rare variants and 13 variants of uncertain significance identified. Median follow-up was 1138 days. Mean LVMI was 82.7 ± 30.6 and 145 patients had late gadolinium enhancement (LGE). Patients with beta-myosin heavy chain (MYH7) mutations had higher LV ejection fraction (68.8 vs 59.1, p<0.001) than those with cardiac myosin binding protein C (MYBPC3) mutations. Patients with MYBPC3 mutations were more likely to have LVEF < 55% (29.7% vs 4.9%, p = 0.005) or receive a defibrillator than those with MYH7 mutations (54.1% vs 26.8%, p = 0.020).We found that patients with MYBPC3 mutations were more likely to have impaired ventricular function and may be more prone to arrhythmic events. Larger studies using CMR phenotyping may be capable of identifying additional characteristics associated with less frequent genetic causes of HCM.

  View details for DOI 10.1371/journal.pone.0217612

  View details for PubMedID 31199839

• Semiautomated Characterization of Carotid Artery Plaque Features From Computed Tomography Angiography to Predict Atherosclerotic Cardiovascular Disease Risk Score. Journal of computer assisted tomography Zhu, G. n., Li, Y. n., Ding, V. n., Jiang, B. n., Ball, R. L., Rodriguez, F. n., Fleischmann, D. n., Desai, M. n., Saloner, D. n., Gupta, A. n., Saba, L. n., Hom, J. n., Wintermark, M. n. 2019

  Abstract

  To investigate whether selected carotid computed tomography angiography (CTA) quantitative features can predict 10-year atherosclerotic cardiovascular disease (ASCVD) risk scores.One hundred seventeen patients with calculated ASCVD risk scores were considered. A semiautomated imaging analysis software was used to segment and quantify plaque features. Eighty patients were randomly selected to build models using 14 imaging variables and the calculated ASCVD risk score as the end point (continuous and binarized). The remaining 37 patients were used as the test set to generate predicted ASCVD scores. The predicted and observed ASCVD risk scores were compared to assess properties of the predictive model.Nine of 14 CTA imaging variables were included in a model that considered the plaque features in a continuous fashion (model 1) and 6 in a model that considered the plaque features dichotomized (model 2). The predicted ASCVD risk scores were 18.87% ± 13.26% and 18.39% ± 11.6%, respectively. There were strong correlations between the observed ASCVD and the predicted ASCVDs, with r = 0.736 for model 1 and r = 0.657 for model 2. The mean biases between observed ASCVD and predicted ASCVDs were -1.954% ± 10.88% and -1.466% ± 12.04%, respectively.Selected quantitative imaging carotid features extracted from the semiautomated carotid artery analysis can predict the ASCVD risk scores.

  View details for PubMedID 31082978

• Cardiopulmonary-induced deformations of the thoracic aorta following thoracic endovascular aortic repair. Vascular Suh, G., Ullery, B. W., Lee, J. T., Dake, M. D., Fleischmann, D., Cheng, C. 2018: 1708538118811204

  Abstract

  OBJECTIVES: Thoracic endovascular aortic repair has become a preferred treatment strategy for thoracic aortic aneurysms and dissections. Yet, it is not well understood if the performance of endografts is affected by physiologic strain due to cyclic aortic motion during cardiac pulsation and respiration. We aim to quantify cardiac- and respiratory-induced changes of the postthoracic endovascular aortic repair thoracic aorta and endograft geometries.METHODS: Fifteen thoracic endovascular aortic repair patients (66±10 years) underwent cardiac-resolved computed tomography angiographies during inspiratory/expiratory breath holds. The computed tomography angiography images were utilized to build models of the aorta, and lumen centerlines and cross-sections were extracted. Arclength and curvature were computed from the lumen centerline. Effective diameter was computed from cross-sections of the thoracic aorta. Deformation was computed from the mid-diastole to end-systole (cardiac deformation) and expiration to inspiration (respiratory deformation).RESULTS: Cardiac pulsation induced significant changes in arclength, mean curvature, maximum curvature change, and effective diameter of the ascending aorta, as well as effective diameter of the stented aortic segment. Respiration, however, induced significant change in mean curvature and effective diameter of the ascending aorta only. Cardiac-induced arclength change of the ascending aorta was significantly greater than respiratory-induced arclength change.CONCLUSIONS: Deformations are present across the thoracic aorta due to cardiopulmonary influences after thoracic endovascular aortic repair. The geometric deformations are greatest in the ascending aorta and decline at the stented thoracic aorta. Additional investigation is warranted to correlate aortic deformation to endograft performance.

  View details for PubMedID 30426849

• Diagnostic Accuracy of a Novel Stress Echocardiography Pattern for Myocardial Bridge in Patients With Angina and No Obstructive Coronary Artery Disease - a Retrospective and Prospective Validation Cohort Study Pargaonkar, V. S., Rogers, I. S., Su, J., Forsdahl, S., Schreiber, D., Chan, F. P., Becker, H., Fleischmann, D., Tremmel, J. A., Schnittger, I. LIPPINCOTT WILLIAMS & WILKINS. 2018

  View details for Web of Science ID 000528619402033

• Personalized Treatment Based on Imaging Parameters and Clinical Parameters Reduces the Risk of Late Adverse Events in Patients With Initially Uncomplicated Type B Aortic Dissections Sailer, K. M., Nelemans, P. J., Willemink, M. J., Hahn, L. D., Higashigaito, K., Fleischmann, D. LIPPINCOTT WILLIAMS & WILKINS. 2018

  View details for Web of Science ID 000528619403423

• Assessing the Relationship Between American Heart Association Atherosclerotic Cardiovascular Disease Risk Score and Coronary Artery Imaging Findings JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Li, Y., Zhu, G., Ding, V., Jiang, B., Ball, R. L., Ahuja, N., Rodriguez, F., Fleischmann, D., Desai, M., Saloner, D., Saba, L., Wintermark, M., Hom, J. 2018; 42 (6): 898–905

  View details for DOI 10.1097/RCT.0000000000000823

  View details for Web of Science ID 000451395400012

• Photon-counting CT: Technical Principles and Clinical Prospects RADIOLOGY Willemink, M. J., Persson, M., Pourmorteza, A., Pelc, N., Fleischmann, D. 2018; 289 (2): 293–312

  View details for DOI 10.1148/radiol.2018172656

  View details for Web of Science ID 000447652300003

• Improving Spatial Resolution at CT: Development, Benefits, and Pitfalls RADIOLOGY Wang, J., Fleischmann, D. 2018; 289 (1): 261–62

  View details for DOI 10.1148/radiol.2018181156

  View details for Web of Science ID 000444990900040

• Photon-counting CT: Technical Principles and Clinical Prospects. Radiology Willemink, M. J., Persson, M., Pourmorteza, A., Pelc, N. J., Fleischmann, D. 2018: 172656

  Abstract

  Photon-counting CT is an emerging technology with the potential to dramatically change clinical CT. Photon-counting CT uses new energy-resolving x-ray detectors, with mechanisms that differ substantially from those of conventional energy-integrating detectors. Photon-counting CT detectors count the number of incoming photons and measure photon energy. This technique results in higher contrast-to-noise ratio, improved spatial resolution, and optimized spectral imaging. Photon-counting CT can reduce radiation exposure, reconstruct images at a higher resolution, correct beam-hardening artifacts, optimize the use of contrast agents, and create opportunities for quantitative imaging relative to current CT technology. In this review, the authors will explain the technical principles of photon-counting CT in nonmathematical terms for radiologists and clinicians. Following a general overview of the current status of photon-counting CT, they will explain potential clinical applications of this technology.

  View details for PubMedID 30179101

• The impact of dose reduction on the quantification of coronary artery calcifications and risk categorization: A systematic review JOURNAL OF CARDIOVASCULAR COMPUTED TOMOGRAPHY Vonder, M., van der Werf, N. R., Leiner, T., Greuter, M. W., Fleischmann, D., Vliegenthart, R., Oudkerk, M., Willemink, M. J. 2018; 12 (5): 352–63

  Abstract

  Multiple dose reduction techniques have been introduced for coronary artery calcium (CAC) computed tomography (CT), but few have emerged into clinical practice while an increasing number of patients undergo CAC scanning. We sought to determine to what extend the radiation dose in CAC CT can be safely reduced without a significant impact on cardiovascular disease (CVD) risk stratification. A systematic database-review of articles published from 2002 until February 2018 was performed in Pubmed, WebOfScience, and Embase. Eligible studies reported radiation dose reduction for CAC CT, calcium scores and/or risk stratification for phantom or patient studies. Twenty-eight studies were included, under which 17 patient studies, 10 phantom/ex-vivo studies, and 1 study evaluated both phantom and patients. Dose was reduced with tube voltage reduction and tube current reduction with and without iterative reconstruction (IR), and tin-filter spectral shaping. The different dose reduction techniques resulted in varying final radiation doses and had varying impact on CAC scores and CVD risk stratification. In 78% of the studies the radiation dose was reduced by ≥ 50% ranging from (CTDIvol) 0.6-5.5 mGy, leading to reclassification rates ranging between 3% and 21%, depending on the acquisition technique. Specific dose reduced protocols, including either tube current reduction and IR or spectral shaping with tin filtration, that showed low reclassification rates may potentially be used in CAC scanning and in future population-based screening for CVD risk stratification.

  View details for PubMedID 29960743

• Improving Spatial Resolution at CT: Development, Benefits, and Pitfalls. Radiology Wang, J., Fleischmann, D. 2018: 181156

  View details for PubMedID 29944083

• Epidemiology and contemporary management of abdominal aortic aneurysms ABDOMINAL RADIOLOGY Ullery, B. W., Hallett, R. L., Fleischmann, D. 2018; 43 (5): 1032–43

  Abstract

  Abdominal aortic aneurysm (AAA) is most commonly defined as a maximal diameter of the abdominal aorta in excess of 3 cm in either anterior-posterior or transverse planes or, alternatively, as a focal dilation ≥ 1.5 times the diameter of the normal adjacent arterial segment. Risk factors for the development of AAA include age > 60, tobacco use, male gender, Caucasian race, and family history of AAA. Aneurysm growth and rupture risk appear to be associated with persistent tobacco use, female gender, and chronic pulmonary disease. The majority of AAAs are asymptomatic and detected incidentally on various imaging studies, including abdominal ultrasound, and computed tomographic angiography. Symptoms associated with AAA may include abdominal or back pain, thromboembolization, atheroembolization, aortic rupture, or development of an arteriovenous or aortoenteric fistula. The Screening Abdominal Aortic Aneurysms Efficiently (SAAAVE) Act provides coverage for a one-time screening abdominal ultrasound at age 65 for men who have smoked at least 100 cigarettes and women who have family history of AAA disease. Medical management is recommended for asymptomatic patients with AAAs < 5 cm in diameter and focuses on modifiable risk factors, including smoking cessation and blood pressure control. Primary indications for intervention in patients with AAA include development of symptoms, rupture, rapid aneurysm growth (> 5 mm/6 months), or presence of a fusiform aneurysm with maximum diameter of 5.5 cm or greater. Intervention for AAA includes conventional open surgical repair and endovascular aortic stent graft repair.

  View details for PubMedID 29313113

• Abdominal aortic aneurysms: pre- and post-procedural imaging ABDOMINAL RADIOLOGY Hallett, R. L., Ullery, B. W., Fleischmann, D. 2018; 43 (5): 1044–66

  View details for DOI 10.1007/s00261-018-1520-5

  View details for Web of Science ID 000430288000003

• Geometric Deformations of the Thoracic Aorta and Supra-Aortic Arch Branch Vessels Following Thoracic Endovascular Aortic Repair VASCULAR AND ENDOVASCULAR SURGERY Ullery, B. W., Suh, G., Hirotsu, K., Zhu, D., Lee, J. T., Dake, M. D., Fleischmann, D., Cheng, C. P. 2018; 52 (3): 173–80

  Abstract

  To utilize 3-D modeling techniques to better characterize geometric deformations of the supra-aortic arch branch vessels and descending thoracic aorta after thoracic endovascular aortic repair.Eighteen patients underwent endovascular repair of either type B aortic dissection (n = 10) or thoracic aortic aneurysm (n = 8). Computed tomography angiography was obtained pre- and postprocedure, and 3-D geometric models of the aorta and supra-aortic branch vessels were constructed. Branch angle of the supra-aortic branch vessels and curvature metrics of the ascending aorta, aortic arch, and stented thoracic aortic lumen were calculated both at pre- and postintervention.The left common carotid artery branch angle was lower than the left subclavian artery angles preintervention ( P < .005) and lower than both the left subclavian and brachiocephalic branch angles postintervention ( P < .05). From pre- to postoperative, no significant change in branch angle was found in any of the great vessels. Maximum curvature change of the stented lumen from pre- to postprocedure was greater than those of the ascending aorta and aortic arch ( P < .05).Thoracic endovascular aortic repair results in relative straightening of the stented aortic region and also accentuates the native curvature of the ascending aorta when the endograft has a more proximal landing zone. Supra-aortic branch vessel angulation remains relatively static when proximal landing zones are distal to the left common carotid artery.

  View details for PubMedID 29400263

• PREDICTING MORTALITY WITH AORTOMITRAL CALCIFICATIONS IN 317 TAVR PATIENTS Willemink, M., Maret, E., Moneghetti, K., Kim, J., Haddad, F., Kobayashi, Y., Higashigaito, K., Yeung, A., Lee, A., Miller, D., Fischbein, M., Fearon, W., Fleischmann, D. ELSEVIER SCIENCE INC. 2018: 1591

  View details for DOI 10.1016/S0735-1097(18)32132-6

  View details for Web of Science ID 000429659703241

• THE PROGNOSTIC VALUE OF COMPUTED TOMOGRAPHY FRAILTY MEASURES FOR PROLONGED HOSPITAL STAY AFTER TAVR IN 429 PATIENTS Maret, E., Willemink, M., Moneghetti, K., Kim, J., Haddad, F., Kobayashi, Y., Miller, C., Yeung, A., Fishbein, M., Fearon, W., Fleischmann, D. ELSEVIER SCIENCE INC. 2018: 1414

  View details for DOI 10.1016/S0735-1097(18)31955-7

  View details for Web of Science ID 000429659703064

• Abdominal aortic aneurysms: pre- and post-procedural imaging. Abdominal radiology (New York) Hallett, R. L., Ullery, B. W., Fleischmann, D. 2018

  Abstract

  Abdominal aortic aneurysm (AAA) is a relatively common, potentially life-threatening disorder. Rupture of AAA is potentially catastrophic with high mortality. Intervention for AAA is indicated when the aneurysm reaches 5.0-5.5cm or more, when symptomatic, or when increasing in size >10mm/year. AAA can be accurately assessed by cross-sectional imaging including computed tomography angiography and magnetic resonance angiography. Current options for intervention in AAA patients include open surgery and endovascular aneurysm repair (EVAR), with EVAR becoming more prevalent over time. Cross-sectional imaging plays a crucial role in AAA surveillance, pre-procedural assessment, and post-EVAR management. This paper will discuss the current role of imaging in the assessment of AAA patients prior to intervention, in evaluation of procedural complications, and in long-term follow-up of EVAR patients.

  View details for PubMedID 29460048

• Assessing the Relationship between Atherosclerotic Cardiovascular Disease Risk Score and Carotid Artery Imaging Findings. Journal of neuroimaging : official journal of the American Society of Neuroimaging Li, Y. n., Zhu, G. n., Ding, V. n., Huang, Y. n., Jiang, B. n., Ball, R. L., Rodriguez, F. n., Fleischmann, D. n., Desai, M. n., Saloner, D. n., Saba, L. n., Hom, J. n., Wintermark, M. n. 2018

  Abstract

  To characterize the relationship between computed tomography angiography (CTA) imaging characteristics of carotid artery and the 10-year risk of atherosclerotic cardiovascular disease (ASCVD) score.We retrospectively identified all patients who underwent a cervical CTA at our institution from January 2013 to July 2016, extracted clinical information, and calculated the 10-year ASCVD score using the Pooled Cohort Equations from the 2013 ACC/AHA guidelines. We compared the imaging features of artery atherosclerosis derived from the CTAs between low and high risk.One hundred forty-six patients met our inclusion criteria. Patients with an ASCVD score ≥7.5% (64.4%) had significantly more arterial stenosis than patients with an ASCVD score <7.5% (35.6%, P < .001). Maximal plaque thickness was significantly higher (mean 2.33 vs. .42 mm, P < .001) and soft plaques (55.3% vs. 13.5%, P < .001) were significantly more frequent in patients with an ASCVD score ≥7.5%. However, among patients with a 10-year ASCVD score ≥7.5%, 33 (35.1%) had no arterial stenosis, 35 (37.2%) had a maximal plaque thickness less than. 9 mm, and 42 (44.7%) had no soft plaque. Furthermore, among the patients with a 10-year ASCVD score <7.5%, 8 (15.4%) had some arterial stenosis, 8 (15.4%) had a maximal plaque thickness more than. 9 mm, and 7 (13.5%) had soft plaque.There is some concordance but not a perfect overlap between the 10-year ASCVD risk scores calculated from clinical and blood assessment and carotid artery imaging findings.

  View details for PubMedID 30357980

• Changes in Geometry and Cardiac Deformation of the Thoracic Aorta after Thoracic Endovascular Aortic Repair Hirotsu, K., Suh, G., Lee, J. T., Dake, M. D., Fleischmann, D., Cheng, C. P. ELSEVIER SCIENCE INC. 2018: 83–89

  View details for DOI 10.1016/j.avsg.2017.07.033

  View details for Web of Science ID 000418233100011

• Coronary artery calcium: A technical argument for a new scoring method. Journal of cardiovascular computed tomography Willemink, M. J., van der Werf, N. R., Nieman, K. n., Greuter, M. J., Koweek, L. M., Fleischmann, D. n. 2018

  Abstract

  Coronary artery calcium (CAC) is a strong predictor for future cardiovascular events. Traditionally CAC has been quantified using the Agatston score, which was developed in the late 1980s for electron beam tomography (EBT). While EBT has been completely replaced by modern multiple-detector row CT technology, the traditional CAC scoring method by Agatston remains in use, although the literature indicates suboptimal reproducibility and subjects being incorrectly classified. The traditional Agatston scoring method counteracts the technical advances of CT technology, and prevents the use of thinner sections, obtained at lower tube voltage and overall decreased radiation exposure that has become available to other CT applications. Moreover, recent studies have shown that not only the total amount of CAC, but also its density and distribution in the coronary arterial tree may be of prognostic value. Acquisition and reconstruction techniques thus need to be adapted for modern CT technology and optimized for CAC quantification. In this review we describe the technical limitations of the Agatston score followed by our suggestions for developing a new and more robust CAC quantification method.

  View details for PubMedID 30366859

• Assessing the Relationship Between American Heart Association Atherosclerotic Cardiovascular Disease Risk Score and Coronary Artery Imaging Findings. Journal of computer assisted tomography Li, Y. n., Zhu, G. n., Ding, V. n., Jiang, B. n., Ball, R. L., Ahuja, N. n., Rodriguez, F. n., Fleischmann, D. n., Desai, M. n., Saloner, D. n., Saba, L. n., Wintermark, M. n., Hom, J. n. 2018

  Abstract

  The aim of this study was to characterize the relationship between computed tomography angiography imaging characteristics of coronary artery and atherosclerotic cardiovascular disease (ASCVD) score.We retrospectively identified all patients who underwent a coronary computed tomography angiography at our institution from December 2013 to July 2016, then we calculated the 10-year ASCVD score. We characterized the relationship between coronary artery imaging findings and ASCVD risk score.One hundred fifty-one patients met our inclusion criteria. Patients with a 10-year ASCVD score of 7.5% or greater had significantly more arterial segments showing stenosis (46.4%, P = 0.008) and significantly higher maximal plaque thickness (1.25 vs 0.53, P = 0.001). However, among 56 patients with a 10-year ASCVD score of 7.5% or greater, 30 (53.6%) had no arterial stenosis. Furthermore, among the patients with a 10-year ASCVD score of less than 7.5%, 24 (25.3%) had some arterial stenosis.There is some concordance but not a perfect overlap between 10-year ASCVD risk scores and coronary artery imaging findings.

  View details for PubMedID 30407249

• Changes in Geometry and Cardiac Deformation of the Thoracic Aorta after Thoracic Endovascular Aortic Repair. Annals of vascular surgery Hirotsu, K., Suh, G., Lee, J. T., Dake, M. D., Fleischmann, D., Cheng, C. P. 2017

  Abstract

  BACKGROUND: Thoracic endovascular aortic repair (TEVAR) has dramatically expanded treatment options for patients with thoracic aortic pathology. The interaction between endografts and the dynamic anatomy of the thoracic aorta is not well characterized for repetitive physiologic stressors and subsequent issues related to long-term durability. Through three-dimensional (3D) modeling we sought to quantify cardiac-induced aortic deformation before and after TEVAR to assess the impact of endografts on dynamic aortic anatomy.METHODS: Eight patients with acute (n=4) or chronic (n=3) type B dissections, or chronic arch aneurysm (n=1), underwent TEVAR with a single (n=5) or multiple (n=3) Gore C-TAG(s). Cardiac-resolved thoracic CT images were acquired pre- and post-TEVAR. 3D models of thoracic aorta and branch vessels were constructed in systole and diastole. Axial length, mean, and peak curvature of the ascending aorta, arch, and stented lumens were computed from the aortic lumen centerline, delineated with branch vessel landmarks. Cardiac-induced deformation was computed from mid-diastole to end-systole.RESULTS: Pre-TEVAR, there were no significant cardiac-induced changes for aortic axial length or mean curvature. Post-TEVAR, the ascending aorta increased in axial length (2.7±3.1%, P<0.05) and decreased in mean curvature (0.38±0.05 0.36±0.05cm-1, P<0.05) from diastole to systole. From pre- to post-TEVAR, axial length change increased in the ascending aorta (P<0.02), mean curvature decreased in the arch and stented aorta (P<0.03), and peak curvature decreased in the stented aorta (P<0.05).CONCLUSIONS: TEVAR for a range of indications not only causes direct geometric changes to the stented aorta but also results in dynamic changes to the ascending and stented aorta. In our cohort, endograft placement straightens the stented aorta and mutes cardiac-induced bending due to longitudinal stiffness. This is compensated by greater length and curvature changes from diastole to systole in the ascending aorta, relative to pre-TEVAR.

  View details for PubMedID 28887263

• Impact of Discordant Views in the Management of Descending Thoracic Aortic Aneurysm SEMINARS IN THORACIC AND CARDIOVASCULAR SURGERY Chiu, P., Sailer, A., Baiocchi, M., Goldstone, A. B., Schaffer, J. M., Trojan, J., Fleischmann, D., Mitchell, R., Miller, D., Dake, M. D., Woo, Y., Lee, J. T., Fischbein, M. P. 2017; 29 (3): 283–91

  Abstract

  Thoracic endovascular aortic repair has a lower perceived risk than open surgical repair and has become an increasingly popular alternative. Whether general consensus exists regarding candidacy for either operation among open and endovascular specialists is unknown. A retrospective review of isolated descending thoracic aortic aneurysm at our institution between January 2005 and October 2015 was performed, excluding trauma and dissection. Two cardiac surgeons, 2 cardiovascular surgeons, 1 vascular surgeon, and 1 interventional radiologist gave their preference for open vs endovascular repair. Interobserver agreement was assessed with the kappa coefficient. k-means clustering agnostically grouped various patterns of agreement. The mean rating was predicted using least absolute shrinkage and selection operator regression. Negative binomial regression predicted the discrepancy between our panel of raters and the historical operation. Generalized estimating equation modeling was then used to evaluate the association between the extent of discrepancy and the adverse perioperative outcome. There were 77 patients with preoperative imaging studies. Pairwise interobserver agreement was only fair (median weighted kappa 0.270 [interquartile range 0.211-0.404]). Increasing age and proximal neck length predicted an increasing preference for thoracic endovascular aortic repair in our panel; larger proximal neck diameter predicted a general preference for open surgical repair. Increasing proximal neck diameter predicted a larger discrepancy between our panel and the historical operation. Greater discrepancy was associated with adverse outcome. Substantial disagreement existed among our panel, and an exploratory analysis of the effect of increasing discrepancy demonstrated an association with adverse perioperative outcome. An investigation of the effect of a thoracic aortic team with open and endovascular specialists is warranted.

  View details for PubMedID 29195571

• Lower extremity computed tomography angiography can help predict technical success of endovascular revascularization in the superficial femoral and popliteal artery JOURNAL OF VASCULAR SURGERY Itoga, N. K., Kim, T., Sailer, A. M., Fleischmann, D., Mell, M. W. 2017; 66 (3): 835-+

  View details for DOI 10.1016/j.jvs.2017.02.031

  View details for Web of Science ID 000412559500110

• Quantification of motion of the thoracic aorta after ascending aortic repair of type-A dissection INTERNATIONAL JOURNAL OF COMPUTER ASSISTED RADIOLOGY AND SURGERY Suh, G., Fleischmann, D., Beygui, R. E., Cheng, C. P. 2017; 12 (5): 811-819

  View details for DOI 10.1007/s11548-016-1499-8

  View details for Web of Science ID 000400863100012

• Identification of Pulmonary Hypertension Caused by Left Heart Disease (World Health Organization Group 2) Based on Cardiac Chamber Volumes Derived from Chest CT. Chest Aviram, G., Rozenbaum, Z., Ziv-Baran, T., Berliner, S., Topilsky, Y., Fleischmann, D., Sung, Y. K., Zamanian, R. T., Guo, H. H. 2017

  Abstract

  Evaluations of patients with pulmonary hypertension (PH) commonly include chest computed tomography (CT). We hypothesized that cardiac chamber volumes calculated from the same CT scans can yield additional information to distinguish left heart disease-related PH (WHO Group 2) from other PH subtypes.Patients with right heart catheterization (RHC)-confirmed PH and contrast-enhanced chest CT studies were enrolled in this retrospective multicenter study. Cardiac chamber volumes were calculated using automated segmentation software and compared between Group 2 and non-Group 2 PH patients.This study included 114 PH patients, of whom 27 (24%) were classified as Group 2 based on their pulmonary capillary wedge pressure. Group 2 PH patients exhibited significantly larger median left atrial (LA) volumes (118 vs. 63 mL, P < 0.001), larger median left ventricular (LV) volumes (90 vs. 76 mL, P = 0.02), and smaller median right ventricular (RV) volumes (173 vs. 210 mL, P = 0.005) than non-Group 2 patients. On multivariate analysis adjusted to age, gender, and mean pulmonary arterial pressure, Group 2 PH was significantly associated with larger median LA and LV volumes (P < 0.001 and P = 0.008, respectively), and decreased volume ratios of RA/LA, RV/LV and RV/LA (P = 0.001, P = 0.004, and P < 0.001, respectively). Enlarged LA volumes demonstrated high discriminatory ability for Group 2 PH (AUC=0.92; 95%CI, 0.870-0.968).Volumetric analysis of the cardiac chambers from non-gated chest CTs, particularly with findings of an enlarged LA, exhibited high discriminatory ability for identifying patients with PH due to left heart disease.

  View details for DOI 10.1016/j.chest.2017.04.184

  View details for PubMedID 28506612

• Lower extremity computed tomography angiography can help predict technical success of endovascular revascularization in the superficial femoral and popliteal artery. Journal of vascular surgery Itoga, N. K., Kim, T., Sailer, A. M., Fleischmann, D., Mell, M. W. 2017

  Abstract

  Preprocedural computed tomography angiography (CTA) assists in evaluating vascular morphology and disease distribution and in treatment planning for patients with lower extremity peripheral artery disease (PAD). The aim of the study was to determine the predictive value of radiographic findings on CTA and technical success of endovascular revascularization of occlusions in the superficial femoral artery-popliteal (SFA-pop) region.Medical records and available imaging studies were reviewed for patients undergoing endovascular intervention for PAD between January 2013 and December 2015 at a single academic institution. Radiologists reviewed preoperative CTA scans of patients with occlusions in the SFA-pop region. Radiographic criteria previously used to evaluate chronic occlusions in the coronary arteries were used. Technical success, defined as restoration of inline flow through the SFA-pop region with <30% stenosis at the end of the procedure, and intraoperative details were evaluated.From 2013 to 2015, there were 407 patients who underwent 540 endovascular procedures for PAD. Preprocedural CTA scans were performed in 217 patients (53.3%), and 84 occlusions in the SFA-pop region were diagnosed. Ten occlusions were excluded as no endovascular attempt to cross the lesion was made because of extensive disease or concomitant iliac intervention. Of the remaining 74 occlusions in the SFA-pop region, 59 were successfully treated (80%) and 15 were unsuccessfully crossed (20%). The indications for revascularization were claudication in 57% of patients and critical limb ischemia in the remaining patients. TransAtlantic Inter-Society Consensus A, B, and C occlusions were treated with 87% success, whereas D occlusions were treated with 68% success (P = .047). There were nine occlusions with 100% vessel calcification that was associated with technical failure (P = .014). Longer lengths of occlusion were also associated with technical failure (P = .042). Multiple occlusions (P = .55), negative remodeling (P = .69), vessel runoff (P = .56), and percentage of vessel calcification (P = .059) were not associated with failure. On multivariable analysis, 100% calcification remained the only significant predictor of technical failure (odds ratio, 9.0; 95% confidence interval, 1.8-45.8; P = .008).Analysis of preoperative CTA shows 100% calcification as the best predictor of technical failure of endovascular revascularization of occlusions in the SFA-pop region. Further studies are needed to determine the cost-effectiveness of obtaining preoperative CTA for lower extremity PAD.

  View details for DOI 10.1016/j.jvs.2017.02.031

  View details for PubMedID 28502550

• Reduced dose CT with model-based iterative reconstruction compared to standard dose CT of the chest, abdomen, and pelvis in oncology patients: intra-individual comparison study on image quality and lesion conspicuity. Abdominal radiology Morimoto, L. N., Kamaya, A., Boulay-Coletta, I., Fleischmann, D., Molvin, L., Tian, L., Fisher, G., Wang, J., Willmann, J. K. 2017

  Abstract

  To compare image quality and lesion conspicuity of reduced dose (RD) CT with model-based iterative reconstruction (MBIR) compared to standard dose (SD) CT in patients undergoing oncological follow-up imaging.Forty-four cancer patients who had a staging SD CT within 12 months were prospectively included to undergo a weight-based RD CT with MBIR. Radiation dose was recorded and tissue attenuation and image noise of four tissue types were measured. Reproducibility of target lesion size measurements of up to 5 target lesions per patient were analyzed. Subjective image quality was evaluated for three readers independently utilizing 4- or 5-point Likert scales.Median radiation dose reduction was 46% using RD CT (P < 0.01). Median image noise across all measured tissue types was lower (P < 0.01) in RD CT. Subjective image quality for RD CT was higher (P < 0.01) in regard to image noise and overall image quality; however, there was no statistically significant difference regarding image sharpness (P = 0.59). There were subjectively more artifacts on RD CT (P < 0.01). Lesion conspicuity was subjectively better in RD CT (P < 0.01). Repeated target lesion size measurements were highly reproducible both on SD CT (ICC = 0.987) and RD CT (ICC = 0.97).RD CT imaging with MBIR provides diagnostic imaging quality and comparable lesion conspicuity on follow-up exams while allowing dose reduction by a median of 46% compared to SD CT imaging.

  View details for DOI 10.1007/s00261-017-1140-5

  View details for PubMedID 28417170

• Perfusion CT measurements predict tumor response in rectal carcinoma ABDOMINAL RADIOLOGY Kino, A., Shaffer, J., Maturen, K. E., Schmiedeskamp, H., Koong, A. C., Chang, D. T., Fleischmann, D., Kamaya, A. 2017; 42 (4): 1132-1140

  View details for DOI 10.1007/s00261-016-0983-5

  View details for Web of Science ID 000399166800010

• Myocardial Bridges on Coronary Computed Tomography Angiography　- Correlation With Intravascular Ultrasound and Fractional Flow Reserve. Circulation Journal Forsdahl, S. H., Rogers, I. S., Schnittger, I., et al 2017

  View details for DOI 10.1253/circj.CJ-17-0284

• Reducing Functional MR Imaging Acquisition Times by Optimizing Workflow RADIOGRAPHICS Chwang, W. B., Iv, M., Smith, J., Kalnins, A., Mickelsen, J., Bammer, R., Fleischmann, D., Larson, D. B., Wintermark, M., Zeineh, M. 2017; 37 (1): 315-321

  Abstract

  Functional magnetic resonance (MR) imaging is a complex, specialized examination that is able to noninvasively measure information critical to patient care such as hemispheric language lateralization ( 1 ). Diagnostic functional MR imaging requires extensive patient interaction as well as the coordinated efforts of the entire health care team. We observed in our practice at an academic center that the times to perform functional MR imaging examinations were excessively lengthy, making scheduling of the examination difficult. The purpose of our project was to reduce functional MR imaging acquisition times by increasing the efficiency of our workflow, using specific quality tools to drive improvement of functional MR imaging. We assembled a multidisciplinary team and retrospectively reviewed all functional MR imaging examinations performed at our institution from January 2013 to August 2015. We identified five key drivers: (a) streamlined protocols, (b) consistent patient monitoring, (c) clear visual slides and audio, (d) improved patient understanding, and (e) minimized patient motion. We then implemented four specific interventions over a period of 10 months: (a) eliminating intravenous contrast medium, (b) reducing repeated language paradigms, (c) updating technologist and physician checklists, and (d) updating visual slides and audio. Our mean functional MR imaging acquisition time was reduced from 76.3 to 53.2 minutes, while our functional MR imaging examinations remained of diagnostic quality. As a result, we reduced our routine scheduling time for functional MR imaging from 2 hours to 1 hour, improving patient comfort and satisfaction as well as saving time for additional potential MR imaging acquisitions. Our efforts to optimize functional MR imaging workflow constitute a practice quality improvement project that is beneficial for patient care and can be applied broadly to other functional MR imaging practices. (©)RSNA, 2017.

  View details for DOI 10.1148/rg.2017160035

  View details for Web of Science ID 000397205200021

• The use of intraosseous needles for injection of contrast media for computed tomographic angiography of the thoracic aorta. Journal of cardiovascular computed tomography Winkler, M. n., Talley, C. n., Woodward, C. n., Kingsbury, A. n., Appiah, F. n., Elbelasi, H. n., Landwher, K. n., Li, X. n., Fleischmann, D. n. 2017

  Abstract

  The objective of this study is to evaluate the safety and quality of computed tomographic angiography of the thoracic aorta (CTA-TA) exams performed using intraosseous needle intravenous access (ION-IVA) for contrast media injection (CMI).All CTA-TA exams at the study institution performed between 1/1/2013 and 8/14/2015 were reviewed retrospectively to identify those exams which had been performed using ION-IVA (ION-exams). ION-exams were then analyzed to determine aortic attenuation and contrast-to-noise ratio (CNR). Linear regression was used to determine how injection rate and other variables affected image quality for ION-exams. Patient electronic medical records were reviewed to identify any adverse events related to CTA-TA or ION-IVA.17 (∼0.2%) of 7401 exams were ION-exams. ION-exam CMI rates varied between 2.5 and 4 ml/s. Mean attenuation was 312 HU (SD 88 HU) and mean CNR was 25 (SD 9.9). A strong positive linear association between attenuation and injection rate was found. No immediate or delayed complications related to the ION-exams, or intraosseous needle use in general, occurred.For CTA-TA, ION-IVA appears to be a safe and effective route for CMI at rates up to 4 ml/s.

  View details for PubMedID 28341196

• Myocardial Bridges on Coronary Computed Tomography Angiography　- Correlation With Intravascular Ultrasound and Fractional Flow Reserve. Circulation journal : official journal of the Japanese Circulation Society Forsdahl, S. H., Rogers, I. S., Schnittger, I. n., Tanaka, S. n., Kimura, T. n., Pargaonkar, V. S., Chan, F. P., Fleischmann, D. n., Tremmel, J. A., Becker, H. C. 2017

  Abstract

  Myocardial bridges (MB) are commonly seen on coronary CT angiography (CCTA) in asymptomatic individuals, but in patients with recurrent typical angina symptoms, yet no obstructive coronary artery disease (CAD), evaluation of their potential hemodynamic significance is clinically relevant. The aim of this study was to compare CCTA to invasive coronary angiography (ICA), including intravascular ultrasound (IVUS), to confirm MB morphology and estimate their functional significance in symptomatic patients.Methods and Results:We retrospectively identified 59 patients from our clinical databases between 2009 and 2014 in whom the suspicion for MB was raised by symptoms of recurrent typical angina in the absence of significant obstructive CAD on ICA. All patients underwent CCTA, ICA and IVUS. MB length and depth by CCTA agreed well with length (0.6±23.7 mm) and depth (CT coverage) as seen on IVUS. The product of CT length and depth (CT coverage), (MB muscle index (MMI)), ≥31 predicted an abnormal diastolic fractional flow reserve (dFFR) ≤0.76 with a sensitivity and specificity of 74% and 62% respectively (area under the curve=0.722).In patients with recurrent symptoms of typical angina yet no obstructive CAD, clinicians should consider dynamic ischemia from an MB in the differential diagnosis. The product of length and depth (i.e., MMI) by CCTA may provide some non-invasive insight into the hemodynamic significance of a myocardial bridge, as compared with invasive assessment with dFFR.

  View details for PubMedID 28690285

• Perfusion CT measurements predict tumor response in rectal carcinoma. Abdominal radiology Kino, A., Shaffer, J., Maturen, K. E., Schmiedeskamp, H., Koong, A. C., Chang, D. T., Fleischmann, D., Kamaya, A. 2016

  Abstract

  To evaluate the capacity of perfusion CT imaging to distinguish between complete and incomplete responders after neoadjuvant chemoradiation therapy for rectal carcinoma, with particular attention to segmentation technique.17 patients were evaluated in this prospective IRB-approved study. For each patient, a perfusion CT acquisition was obtained prior to the initiation of chemoradiation, at 1-2 weeks after the start of chemoradiation, and at 12 weeks after the start of chemoradiation therapy. From each dataset, three perfusion parameters were measured, each in two different ways: a region of interest incorporating only "hot spots" of greatest enhancement and whole-tumor measurements.In univariate analysis, blood volume and permeability differed significantly between responders and non-responders. In logistic regression analysis evaluating predictors of the "complete response" outcome, only two predictors were retained as statistically significant: peak hot spot blood volume 1-2 weeks into therapy (OR 10.25, p = 0.0026) and hot spot permeability decline at 12 weeks after the initiation of therapy (OR 5.62, p = 0.03). The overall likelihood ratio test for this model supported the conclusion that hot spot blood volume and hot spot permeability decline were significant predictors of the complete pathologic response outcome (p < 0.0001).In this pilot study, peak tumor blood volume and decline in tumor permeability, when measured in "hot spots" of greatest enhancement, were strong predictors of complete therapeutic response in rectal cancer after neoadjuvant therapy.

  View details for DOI 10.1007/s00261-016-0983-5

  View details for PubMedID 28008455

• Quantification of motion of the thoracic aorta after ascending aortic repair of type-A dissection. International journal of computer assisted radiology and surgery Suh, G., Fleischmann, D., Beygui, R. E., Cheng, C. P. 2016: -?

  Abstract

  To quantify cardiac and respiratory deformations of the thoracic aorta after ascending aortic graft repair.Eight patients were scanned with cardiac-resolved computed tomography angiography during inspiratory/expiratory breath-holds. Aortic centerlines and lumen were extracted to compute the arclength, curvature, angulation, and cross-section shape.From systole to diastole, the angle of graft [Formula: see text] arch increased by 2.4[Formula: see text] ± 1.8[Formula: see text] (P < 0.01) and the angle of arch [Formula: see text] descending aorta decreased by 2.4[Formula: see text] ± 2.6[Formula: see text] (P < 0.05), while the effective diameter of the proximal arch decreased by 2.4 ± 1.9% (P < 0.01), a greater change than those of the graft or distal arch (P < 0.05). From inspiration to expiration, the angle of graft [Formula: see text] arch increased by 2.8[Formula: see text] ± 2.6[Formula: see text] (P < 0.02) with the peak curvature increase (P < 0.05). Shorter graft length was correlated with greater cardiac-induced graft [Formula: see text] arch angulation, and longer graft length was correlated with greater respiratory-induced arch [Formula: see text] descending aorta angulation (R [Formula: see text] 0.50).The thoracic aorta changed curvature and angulation with cardiac and respiratory influences, driven by aortic root and arch motion. The thoracic aortic geometry and deformation are correlated with the ascending aortic graft length.

  View details for PubMedID 27882488

• DNA damage-associated biomarkers in studying individual sensitivity to low-dose radiation from cardiovascular imaging. European heart journal Lee, W. H., Nguyen, P. K., Fleischmann, D., Wu, J. C. 2016; 37 (40): 3075-3080

  View details for PubMedID 27272147

• Volumetric analysis demonstrates that true and false lumen remodeling persists for 12 months after thoracic endovascular aortic repair JOURNAL OF VASCULAR SURGERY CASES AND INNOVATIVE TECHNIQUES Suh, G., Hirotsu, K., Beygui, R. E., Dake, M. D., Fleischmann, D., Cheng, C. P. 2016; 2 (3): 101–4

  View details for DOI 10.1016/j.jvscit.2016.05.001

  View details for Web of Science ID 000438436000012

• Volumetric analysis demonstrates that true and false lumen remodeling persists for 12 months after thoracic endovascular aortic repair. Journal of vascular surgery cases and innovative techniques Suh, G. Y., Hirotsu, K., Beygui, R. E., Dake, M. D., Fleischmann, D., Cheng, C. P. 2016; 2 (3): 101-104

  Abstract

  A 62-year-old man underwent an elephant trunk procedure followed by thoracic endovascular aortic repair (TEVAR). Computed tomography angiography-based models were built to quantify volume of the whole aorta and true and false lumens preoperatively, before TEVAR, after TEVAR, and at follow-up at 3, 6, and 12 months. With TEVAR, descending aortic true lumen volume increased by 54%, then increased additionally by 60% during 12 months. The descending aortic false lumen volume regressed continuously for 12 months following TEVAR, with the most rapid rate from 6 to 12 months at 16 cm3/month. TEVAR immediately increased true lumen volume and continued to remodel the true and false lumens throughout the following 12 months.

  View details for DOI 10.1016/j.jvscit.2016.05.001

  View details for PubMedID 38827208

  View details for PubMedCentralID PMC11140378

• Lower Extremity Computed Tomography Angiography Can Predict Technical Success of Endovascular Revascularization in the Superficial Femoral and Popliteal Arteries Itoga, N. K., Kim, T., Sailer, A. M., Fleischmann, D., Mell, M. W. MOSBY-ELSEVIER. 2016: 539–40

  View details for DOI 10.1016/j.jvs.2016.05.010

  View details for Web of Science ID 000380753300045

• A prototype piecewise-linear dynamic attenuator PHYSICS IN MEDICINE AND BIOLOGY Hsieh, S. S., Peng, M. V., May, C. A., Shunhavanich, P., Fleischmann, D., Pelc, N. J. 2016; 61 (13): 4974-4988

  Abstract

  The piecewise-linear dynamic attenuator has been proposed as a mechanism in CT scanning for personalizing the x-ray illumination on a patient- and application-specific basis. Previous simulations have shown benefits in image quality, scatter, and dose objectives. We report on the first prototype implementation. This prototype is reduced in scale and speed and is integrated into a tabletop CT system with a smaller field of view (25 cm) and longer scan time (42 s) compared to a clinical system. Stainless steel wedges were machined and affixed to linear actuators, which were in turn held secure by a frame built using rapid prototyping technologies. The actuators were computer-controlled, with characteristic noise of about 100 microns. Simulations suggest that in a clinical setting, the impact of actuator noise could lead to artifacts of only 1 HU. Ring artifacts were minimized by careful design of the wedges. A water beam hardening correction was applied and the scan was collimated to reduce scatter. We scanned a 16 cm water cylinder phantom as well as an anthropomorphic pediatric phantom. The artifacts present in reconstructed images are comparable to artifacts normally seen with this tabletop system. Compared to a flat-field reference scan, increased detectability at reduced dose is shown and streaking is reduced. Artifacts are modest in our images and further refinement is possible. Issues of mechanical speed and stability in the challenging clinical CT environment will be addressed in a future design.

  View details for DOI 10.1088/0031-9155/61/13/4974

  View details for Web of Science ID 000378094000015

  View details for PubMedID 27284705

  View details for PubMedCentralID PMC4937875

• Endovascular treatment of complex aortic aneurysms: prevalence of acute kidney injury and effect on long-term renal function EUROPEAN RADIOLOGY Sailer, A. M., Nelemans, P. J., van Berlo, C., Yazar, O., de Haan, M. W., Fleischmann, D., Schurink, G. W. 2016; 26 (6): 1613-1619

  Abstract

  To analyse predictors for short- and long-term renal function changes after fenestrated and branched endovascular aortic repair (EVAR).A total of 157 patients underwent fenestrated and branched EVAR. Procedural intra-arterial iodinated contrast volume was documented. Serum creatinine and estimated glomerular filtration rate (eGFR) at baseline, during 48 h following EVAR, at discharge and latest moment of follow-up were recorded. Development of post-EVAR acute kidney injury (AKI; according to AKIN criteria), and potential risk factors for renal failure were recorded. Multivariate regression analyses were used to identify independent risk factors for AKI and eGFR decrease during follow-up.Forty-three patients (28 %) developed post-EVAR AKI. Long procedure time and occlusion of accessory renal arteries were independent risk factors for development of AKI. (odds ratio (OR) 1.005 per minute, 95 % CI 1.001-1.01; p = 0.025 and OR 3.02, 95 % CI 1.19-8.16; p = 0.029). Post-EVAR AKI was associated with a significantly increased risk for eGFR decrease at discharge and latest follow-up (hazard ratio (HR) 3.47, 95 % CI 1.63-7.36, p = 0.001 and HR 3.01, 95 % CI 1.56-5.80; p = 0.001). Iodinated contrast volume was not an independent risk factor for AKI or eGFR decrease during follow-up.Development of post-EVAR AKI is an independent risk factor for long-term renal function decrease.• Longer procedure time is associated with an increased risk for AKI. • Renal perfusion defects on angiography are associated with increased risk for AKI. • Post-EVAR AKI is associated with higher probability for long-term eGFR decrease. • Iodinated contrast volume is not an independent risk factor for AKI. • Iodinated contrast volume is not an independent risk factor for long-term eGFR decrease.

  View details for DOI 10.1007/s00330-015-3993-8

  View details for Web of Science ID 000376100100012

  View details for PubMedID 26431707

• Lower Extremity CT Angiography Can Predict Technical Success of Endovascular Revascularization in the Superficial Femoral and Popliteal Arteries Itoga, N. K., Kim, T., Sailer, A. M., Fleischmann, D., Mell, M. W. MOSBY-ELSEVIER. 2016: 198S

  View details for DOI 10.1016/j.jvs.2016.03.334

  View details for Web of Science ID 000376230600315

• Comparative geometric analysis of renal artery anatomy before and after fenestrated or snorkel/chimney endovascular aneurysm repair JOURNAL OF VASCULAR SURGERY Ullery, B. W., Suh, G., Lee, J. T., Liu, B., Stineman, R., Daman, R. L., Cheng, C. P. 2016; 63 (4): 922-929

  Abstract

  The durability of stent grafts may be related to how procedures and devices alter native anatomy. We aimed to quantify and compare renal artery geometry before and after fenestrated (F-) or snorkel/chimney (Sn-) endovascular aneurysm repair (EVAR).Forty patients (75 ± 6 years) underwent computed tomographic angiography before and after F-EVAR (n = 21) or Sn-EVAR (n = 19), with a total of 72 renal artery stents. Renal artery geometry was quantified using three-dimensional model-based centerline extraction. The stented length was computed from the vessel origin to the stent end. The branch angle was computed relative to the orthogonal configuration with respect to the aorta. The end-stent angle was computed relative to the distal native renal artery. Peak curvature was defined as the inverse of the radius of the circumscribed circle at the highest curvature within the proximal portion from the origin to the stent end and the distal portion from the stent end to the first renal artery bifurcation.Sn-renals had greater stented length compared to F-renals (P < .05). From the pre- to the postoperative period, the origins of the Sn-left renal artery and right renal artery (RRA) angled increasingly downward by 21 ± 19° and 13 ± 17°, respectively (P < .005). The F-left renal artery and RRA angled upward by 25 ± 15° and 14 ± 15°, respectively (P < .005). From the pre- to the postoperative period, the end-stent angle of the Sn-RRA increased by 17 ± 12° (P < .00001), with greater magnitude change compared to the F-RRA (P < .0005). Peak curvature increased in distal Sn-RRAs by .02 ± .03 mm(-1) (P < .05). Acute renal failure occurred in 12.5% of patients, although none required dialysis following either F- and Sn-EVAR. Renal stent patency was 97.2% at mean follow-up of 13.7 months. Three type IA endoleaks were identified, prompting one secondary procedure, with the remainder resolving at 6-month follow-up. One renal artery reintervention was performed due to a compressed left renal stent in an asymptomatic patient.Stented renal arteries were angled more inferiorly after Sn-EVAR and more superiorly after F-EVAR due to stent configuration. Sn-EVAR induced significantly greater angle change at the stent end and curvature change distal to the stent compared to F-EVAR, although no difference in patency was noted in this small series with relatively short follow-up. Sn-RRAs exhibited greater end-stent angle change from the pre- to the postoperative period as compared to the F-RRA. These differences may exert differential effects on long-term renal artery patency, integrity, and renal function following complex EVAR for juxta- or pararenal abdominal aortic aneurysms.

  View details for DOI 10.1016/j.jvs.2015.10.091

  View details for Web of Science ID 000372958200012

• Regional right ventricular dysfunction in acute pulmonary embolism: relationship with clot burden and biomarker profile INTERNATIONAL JOURNAL OF CARDIOVASCULAR IMAGING Tuzovic, M., Adigopula, S., Amsallem, M., Kobayashi, Y., Kadoch, M., Boulate, D., Krishnan, G., Liang, D., Schnittger, I., Fleischmann, D., McConnell, M. V., Haddad, F. 2016; 32 (3): 389-398

  Abstract

  Regional right ventricular (RV) dysfunction (RRVD) is an echocardiographic feature in acute pulmonary embolism (PE), primarily reported in patients with moderate-to-severe RV dysfunction. This study investigated the clinical importance of RRVD by assessing its relationship with clot burden and biomarkers. We identified consecutive patients admitted to the emergency department between 1999 and 2014 who underwent computed tomographic angiography, echocardiography, and biomarker testing (troponin and NT-proBNP) for suspected acute PE. RRVD was defined as normal excursion of the apex contrasting with hypokinesis of the mid-free wall segment. RV assessment included measurements of ventricular dimensions, fractional area change, free-wall longitudinal strain and tricuspid annular plane systolic excursion. Clot burden was assessed using the modified Miller score. Of 82 patients identified, 51 had acute PE (mean age 66 ± 17 years, 43 % male). No patient had RV myocardial infarction. RRVD was present in 41 % of PEs and absent in all patients without PE. Among patients with PE, 86 % of patients with RRVD had central or multi-lobar PE. Patients with RRVD had higher prevalence of moderate-to-severe RV dilation (81 vs. 30 %, p < 0.01) and dysfunction (86 vs. 23 %, p < 0.01). There was a strong trend for higher troponin level in PE patients with RRVD (38 vs. 13 % in PE patients without RRVD, p = 0.08), while there was no significant difference for NT-proBNP (67 vs. 73 %, p = 0.88). RRVD showed good concordance between readers (87 %). RRVD is associated with an increased clot burden in acute PE and is more prevalent among patients with moderate-to-severe RV enlargement and dysfunction.

  View details for DOI 10.1007/s10554-015-0780-1

  View details for PubMedID 26428674

• A limit on dose reduction possible with CT reconstruction algorithms without prior knowledge of the scan subject. Medical physics Hsieh, S. S., Chesler, D. A., Fleischmann, D., Pelc, N. J. 2016; 43 (3): 1361-?

  Abstract

  To find an upper bound on the maximum dose reduction possible for any reconstruction algorithm, analytic or iterative, that result from the inclusion of the data statistics. The authors do not analyze noise reduction possible from prior knowledge or assumptions about the object.The authors examined the task of estimating the density of a circular lesion in a cross section. Raw data were simulated by forward projection of existing images and numerical phantoms. To assess an upper bound on the achievable dose reduction by any algorithm, the authors assume that both the background and the shape of the lesion are completely known. Under these conditions, the best possible estimate of the density can be determined by solving a weighted least squares problem directly in the raw data domain. Any possible reconstruction algorithm that does not use prior knowledge or make assumptions about the object, including filtered backprojection (FBP) or iterative reconstruction methods with this constraint, must be no better than this least squares solution. The authors simulated 10 000 sets of noisy data and compared the variance in density from the least squares solution with those from FBP. Density was estimated from FBP images using either averaging within a ROI, or streak-adaptive averaging with better noise performance.The bound on the possible dose reduction depends on the degree to which the observer can read through the possibly streaky noise. For the described low contrast detection task with the signal shape and background known exactly, the average dose reduction possible compared to FBP with streak-adaptive averaging was 42% and it was 64% if only the ROI average is used with FBP. The exact amount of dose reduction also depends on the background anatomy, with statistically inhomogeneous backgrounds showing greater benefits.The dose reductions from new, statistical reconstruction methods can be bounded. Larger dose reductions in the density estimation task studied here are only possible with the introduction of prior knowledge, which can introduce bias.

  View details for DOI 10.1118/1.4941954

  View details for PubMedID 26936720

  View details for PubMedCentralID PMC4769269

• Computed Tomography Angiography A Review and Technical Update RADIOLOGIC CLINICS OF NORTH AMERICA Fleischmann, D., Chin, A. S., Molvin, L., Wang, J., Hallett, R. 2016; 54 (1): 1-?

  Abstract

  The principles of computed tomography angiography (CTA) remain the following with modern-day computed tomography (CT): high-resolution volumetric CT data acquisition, imaging at maximum contrast medium enhancement, and subsequent angiographic two- and three-dimensional visualization. One prerequisite for adapting CTA to ever evolving CT technology is understanding the principle rules of contrast medium enhancement. Four key rules of early arterial contrast dynamics can help one understand the relationship between intravenously injected contrast medium and the resulting time-dependent arterial enhancement. The technical evolution of CT has continued with many benefits for CT angiography. Well-informed adaptations of CTA principles allow for leveraging of these innovations for the benefit of patients with cardiovascular diseases.

  View details for DOI 10.1016/j.rcl.2015.09.002

  View details for Web of Science ID 000367215000002

  View details for PubMedID 26654388

• Contrast Medium Injection Technique MULTIDETECTOR-ROW CT OF THE THORAX, 2ND EDITION Fleischmann, D., Hallett, R. L., Schoepf, U. J., Meinel, F. G. 2016: 37–57

  View details for DOI 10.1007/978-3-319-30355-0_3

  View details for Web of Science ID 000398031100005

• Computed Tomography Angiography of the Upper Extremities RADIOLOGIC CLINICS OF NORTH AMERICA Dave, R. B., Fleischmann, D. 2016; 54 (1): 101-?

  View details for DOI 10.1016/j.rcl.2015.08.008

  View details for PubMedID 26654394

• Pre- and Postoperative Imaging of the Aortic Root. Radiographics Hanneman, K., Chan, F. P., Mitchell, R. S., Miller, D. C., Fleischmann, D. 2016; 36 (1): 19-37

  Abstract

  Three-dimensional datasets acquired using computed tomography and magnetic resonance imaging are ideally suited for characterization of the aortic root. These modalities offer different advantages and limitations, which must be weighed according to the clinical context. This article provides an overview of current aortic root imaging, highlighting normal anatomy, pathologic conditions, imaging techniques, measurement thresholds, relevant surgical procedures, postoperative complications and potential imaging pitfalls. Patients with a range of clinical conditions are predisposed to aortic root disease, including Marfan syndrome, bicuspid aortic valve, vascular Ehlers-Danlos syndrome, and Loeys-Dietz syndrome. Various surgical techniques may be used to repair the aortic root, including placement of a composite valve graft, such as the Bentall and Cabrol procedures; placement of an aortic root graft with preservation of the native valve, such as the Yacoub and David techniques; and implantation of a biologic graft, such as a homograft, autograft, or xenograft. Potential imaging pitfalls in the postoperative period include mimickers of pathologic processes such as felt pledgets, graft folds, and nonabsorbable hemostatic agents. Postoperative complications that may be encountered include pseudoaneurysms, infection, and dehiscence. Radiologists should be familiar with normal aortic root anatomy, surgical procedures, and postoperative complications, to accurately interpret pre- and postoperative imaging performed for evaluation of the aortic root. Online supplemental material is available for this article. (©)RSNA, 2015.

  View details for DOI 10.1148/rg.2016150053

  View details for PubMedID 26761529

• Geometric analysis of thoracic aorta and arch branches before and after TEVAR Suh, G., Hirotsu, K., Zhu, Y. D., Lee, J., Dake, M., Fleischmann, D., Cheng, C. ELSEVIER SCIENCE INC. 2015: B129

  View details for DOI 10.1016/j.jacc.2015.08.340

  View details for Web of Science ID 000363329000283

• Assessment of the Radiation Effects of Cardiac CT Angiography Using Protein and Genetic Biomarkers. JACC. Cardiovascular imaging Nguyen, P. K., Lee, W. H., Li, Y. F., Hong, W. X., Hu, S., Chan, C., Liang, G., Nguyen, I., Ong, S., Churko, J., Wang, J., Altman, R. B., Fleischmann, D., Wu, J. C. 2015; 8 (8): 873-884

  Abstract

  The purpose of this study was to evaluate whether radiation exposure from cardiac computed tomographic angiography (CTA) is associated with deoxyribonucleic acid (DNA) damage and whether damage leads to programmed cell death and activation of genes involved in apoptosis and DNA repair.Exposure to radiation from medical imaging has become a public health concern, but whether it causes significant cell damage remains unclear.We conducted a prospective cohort study in 67 patients undergoing cardiac CTA between January 2012 and December 2013 in 2 U.S. medical centers. Median blood radiation exposure was estimated using phantom dosimetry. Biomarkers of DNA damage and apoptosis were measured by flow cytometry, whole genome sequencing, and single cell polymerase chain reaction.The median dose length product was 1,535.3 mGy•cm (969.7 to 2,674.0 mGy•cm). The median radiation dose to the blood was 29.8 mSv (18.8 to 48.8 mSv). Median DNA damage increased 3.39% (1.29% to 8.04%, p < 0.0001) and median apoptosis increased 3.1-fold (1.4- to 5.1-fold, p < 0.0001) post-radiation. Whole genome sequencing revealed changes in the expression of 39 transcription factors involved in the regulation of apoptosis, cell cycle, and DNA repair. Genes involved in mediating apoptosis and DNA repair were significantly changed post-radiation, including DDB2 (1.9-fold [1.5- to 3.0-fold], p < 0.001), XRCC4 (3.0-fold [1.1- to 5.4-fold], p = 0.005), and BAX (1.6-fold [0.9- to 2.6-fold], p < 0.001). Exposure to radiation was associated with DNA damage (odds ratio [OR]: 1.8 [1.2 to 2.6], p = 0.003). DNA damage was associated with apoptosis (OR: 1.9 [1.2 to 5.1], p < 0.0001) and gene activation (OR: 2.8 [1.2 to 6.2], p = 0.002).Patients exposed to >7.5 mSv of radiation from cardiac CTA had evidence of DNA damage, which was associated with programmed cell death and activation of genes involved in apoptosis and DNA repair.

  View details for DOI 10.1016/j.jcmg.2015.04.016

  View details for PubMedID 26210695

• Aortoiliac Elongation after Endovascular Aortic Aneurysm Repair ANNALS OF VASCULAR SURGERY Chandra, V., Rouer, M., Garg, T., Fleischmann, D., Mell, M. 2015; 29 (5): 891-897

  Abstract

  Aortoiliac elongation after endovascular aortic aneurysm repair (EVAR) is not well studied. We sought to assess the long-term morphologic changes after EVAR and identify potentially modifiable factors associated with such a change.An institutional review board-approved retrospective review was conducted for 88 consecutive patients who underwent EVAR at a single academic center from 2003 to 2007 and who also had at least 2 follow-up computed tomography angiograms (CTAs) available for review up to 5 years after surgery. Standardized centerline aortic lengths and diameters were obtained on Aquarius iNtuition 3D workstation (TeraRecon Inc., San Mateo, CA) on postoperative and all-available follow-up CTAs. Relationships to aortic elongation were determined using Wilcoxon rank-sum test or linear regression (Stata version 12.1, College Station, TX). Changes in length over time were determined by mixed-effects analysis (SAS version 9.3, Cary, NC).The study cohort was composed of mostly men (88%), with a mean age of (76 ± 8) and a mean follow-up of 3.2 years (range, 0.4-7.5 years). Fifty-seven percent of patients (n = 50) had devices with suprarenal fixation and 43% (n = 38) had no suprarenal fixation. Significant lengthening was observed over the study period in the aortoiliac segments, but not in the iliofemoral segments. Aortoiliac elongation over time was not associated with sex (P = 0.3), hypertension (P = 0.7), coronary artery disease (P = 0.3), diabetes (P = 0.3), or tobacco use (P = 0.4), but was associated with the use of statins (P = 0.03) and the presence of chronic obstructive pulmonary disease (P = 0.02). Significant aortic lengthening was associated with increased type I endoleaks (P = 0.03) and reinterventions (P = 0.03). Over the study period, 4 different devices were used; Zenith (Cook Medical Inc., Bloomington, IN), Talent (Medtronic, Minneapolis, MN), Aneuryx (Medtronic), and Excluder (W. L. Gore and Associates Inc., Flagstaff, AZ). After adjusting for differences in proximal landing zone, significant differences in aortic lengthening over time were observed by device type (P = 0.02).Significant aortoiliac elongation was observed after EVAR. Such morphologic changes may impact long-term durability of EVAR, warranting further investigation into factors associated with these morphologic changes.

  View details for DOI 10.1016/j.avsg.2014.12.041

  View details for Web of Science ID 000356994400003

  View details for PubMedID 25757989

• Novel Approach to a Giant External Iliac Vein Aneurysm Secondary to Posttraumatic Femoral Arteriovenous Fistula VASCULAR AND ENDOVASCULAR SURGERY Thompson, P. C., Ullery, B. W., Fleischmann, D., Chandra, V. 2015; 49 (5-6): 148-151

  Abstract

  We describe a case of a 55-year-old male with a remote history of a gunshot wound to the left thigh who presented with a 1-year history of worsening high-output congestive heart failure, left lower extremity edema, and left lower abdominal discomfort. Diagnostic evaluation included a computed tomographic angiography (CTA) that demonstrated a fistulous communication between the left superficial femoral artery (SFA) and vein (SFV) as well as a 7.2-cm external iliac vein aneurysm. Given his symptomatology, an endovascular repair of his AVF was recommended, followed by antithrombotic therapy for his aneurysm. Three-month postoperative CTA confirmed AVF exclusion as well as a significant decrease in maximal diameter of the left external iliac vein aneurysm now measuring 24 mm. This case is the first reported successful mid-term repair of a iliac venous aneurysm in the setting of a traumatic arteriovenous fistula using an endovascular approach.

  View details for DOI 10.1177/1538574415602781

  View details for Web of Science ID 000361529700008

  View details for PubMedID 26335991

• Noninvasive pulmonary nodule elastometry by CT and deformable image registration. Radiotherapy and oncology Negahdar, M., Fasola, C. E., Yu, A. S., von Eyben, R., Yamamoto, T., Diehn, M., Fleischmann, D., Tian, L., Loo, B. W., Maxim, P. G. 2015; 115 (1): 35-40

  Abstract

  To develop a noninvasive method for determining malignant pulmonary nodule (MPN) elasticity, and compare it against expert dual-observer manual contouring.We analyzed breath-hold images at extreme tidal volumes of 23 patients with 30 MPN treated with stereotactic ablative radiotherapy. Deformable image registration (DIR) was applied to the breath-hold images to determine the volumes of the MPNs and a ring of surrounding lung tissue (ring) in each state. MPNs were also manually delineated on deep inhale and exhale images by two observers. Volumes were compared between observers and DIR by Dice similarity. Elasticity was defined as the absolute value of the volume ratio of the MPN minus one normalized to that of the ring.For all 30 tumors the Dice coefficient was 0.79±0.07 and 0.79±0.06 between DIR with observers 1 and 2, respectively, close to the inter-observer Dice value, 0.81±0.1. The elasticity of MPNs was 1.24±0.26, demonstrating that volume change of the MPN was less than that of the surrounding lung.We developed a noninvasive CT elastometry method based on DIR that measures the elasticity of biopsy-proven MPN. Our future direction would be to develop this method to distinguish malignant from benign nodules.

  View details for DOI 10.1016/j.radonc.2015.03.015

  View details for PubMedID 25824979

• A Crack in the Wall: Evolution of a Left Ventricular Apical Pseudoaneurysm. The Canadian journal of cardiology Parikh, R. V., Ahmadi-Kashani, M. n., Fleischmann, D. n., Woo, Y. J., McConnell, M. V. 2015

  View details for PubMedID 26514751

• OPEN-SOURCE 4D STATISTICAL SHAPE MODEL OF THE HEART FOR X-RAY PROJECTION IMAGING Unberath, M., Maier, A., Fleischmann, D., Hornegger, J., Fahrig, R., IEEE IEEE. 2015: 739–42

  View details for Web of Science ID 000380546000177

• Aortic Arch Vessel Geometries and Deformations in Patients with Thoracic Aortic Aneurysms and Dissections JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Suh, G., Beygui, R. E., Fleischmann, D., Cheng, C. P. 2014; 25 (12): 1903-1911

  Abstract

  To quantify aortic arch geometry and in vivo cardiac-induced and respiratory-induced arch translations and arch branch angulations using three-dimensional geometric modeling techniques.Scanning with electrocardiogram-gated computed tomography angiography during inspiratory and expiratory breath holds was performed in 15 patients (age, 64 y ± 14) with thoracic aortic aneurysms or dissections. From the lumen models, centerlines of the thoracic aorta, brachiocephalic artery, left common carotid artery, and left subclavian artery and their branching ostia positions were quantified. Three-dimensional translation of vessel ostia, branching angles, and their changes secondary to cardiac pulsation and respiration were computed.During expiration, all ostia translated rightward from systole to diastole (P < .035). Regardless of cardiac phase, all ostia translated posteriorly and superiorly from inspiration to expiration (P < .05). Respiration induced greater posterior and superior translations than cardiac pulsation (P < .03). The left common carotid artery branch angled significantly more toward the aortic arch compared with the brachiocephalic artery and left subclavian artery (P < .03). No significant changes in branching angle were found from systole to diastole or inspiration to expiration.In patients with thoracic aortic aneurysms or dissections, the thoracic aortic arch translated significantly secondary to inspiration and expiration and to a lesser extent secondary to cardiac pulsation. Insignificant branching angle changes suggest that the aortic arch and its branch origins move predominantly in unison.

  View details for DOI 10.1016/j.jvir.2014.06.012

  View details for Web of Science ID 000345676700011

  View details for PubMedID 25066591

• Noninvasive Pulmonary Nodule Elastometry by CT and Deformable Image Registration Negahdar, M., Shultz, D. B., Eyben, R. V., Fasola, C., Yu, A. S., Tian, L., Fleischmann, D., Gable, L., Shan, X., Diehn, M., Loo, B. W., Maxim, P. G. ELSEVIER SCIENCE INC. 2014: S10

  View details for DOI 10.1016/j.ijrobp.2014.08.145

  View details for Web of Science ID 000346413500020

• Pediatric CT quality management and improvement program PEDIATRIC RADIOLOGY Larson, D. B., Molvin, L. Z., Wang, J., Chan, F. P., Newman, B., Fleischmann, D. 2014; 44: 519-524

  View details for DOI 10.1007/s00247-014-3039-4

  View details for Web of Science ID 000343721300023

• Pediatric CT quality management and improvement program. Pediatric radiology Larson, D. B., Molvin, L. Z., Wang, J., Chan, F. P., Newman, B., Fleischmann, D. 2014; 44: 519-524

  Abstract

  Modern CT is a powerful yet increasingly complex technology that continues to rapidly evolve; optimal clinical implementation as well as appropriate quality management and improvement in CT are challenging but attainable. This article outlines the organizational structure on which a CT quality management and improvement program can be built, followed by a discussion of common as well as pediatric-specific challenges. Organizational elements of a CT quality management and improvement program include the formulation of clear objectives; definition of the roles and responsibilities of key personnel; implementation of a technologist training, coaching and feedback program; and use of an efficient and accurate monitoring system. Key personnel and roles include a radiologist as the CT director, a qualified CT medical physicist, as well as technologists with specific responsibilities and adequate time dedicated to operation management, CT protocol management and CT technologist education. Common challenges in managing a clinical CT operation are related to the complexity of newly introduced technology, of training and communication and of performance monitoring. Challenges specific to pediatric patients include the importance of including patient size in protocol and dose considerations, a lower tolerance for error in these patients, and a smaller sample size from which to learn and improve.

  View details for DOI 10.1007/s00247-014-3039-4

  View details for PubMedID 25304715

• Noninvasive Pulmonary Nodule Elastometry by CT and Deformable Image Registration Negahdar, M., Shultz, D. B., Eyben, R. V., Fasola, C., Yu, A. S., Tian, L., Fleischmann, D., Gable, L., Shan, X., Diehn, M., Loo, B. W., Maxim, P. G. ELSEVIER SCIENCE INC. 2014: S623–S624

  View details for DOI 10.1016/j.ijrobp.2014.05.1857

  View details for Web of Science ID 000342331402265

• CT findings in acute, subacute, and chronic ischemic colitis: suggestions for diagnosis. BioMed research international Iacobellis, F., Berritto, D., Fleischmann, D., Gagliardi, G., Brillantino, A., Mazzei, M. A., Grassi, R. 2014; 2014: 895248

  Abstract

  This paper aims at evaluating CT findings of occlusive and nonocclusive ischemic colitis (IC), in correlation with the etiology and the different phases of the disease.CT examination and clinical history of 32 patients with proven IC were retrospectively reviewed. The CT findings were analyzed according to the different phases of the disease (acute, subacute, and chronic).Among the 32 CT examinations performed in the acute phase, 62.5% did not present signs of occlusion of the superior mesenteric artery (SMA) or inferior mesenteric artery (IMA), whereas IMA occlusion was detected in 37.5% of CT examinations. In the acute phase, the presence of pericolic fluid was found in 100% of patients undergoing progressive resorption from acute to subacute phase if an effective reperfusion occurred; the bowel wall thickening was observed in 28.1% patients in acute phase and in 86.4% patients evaluated in subacute phase. The unthickened colonic wall was found in all conditions where ischemia was not followed by effective reperfusion (71.9% of cases), and it was never found in chronic phase, when the colon appeared irregularly thickened.CT allows determining the morphofunctional alterations associated with the IC discriminating the occlusive forms from the nonocclusive forms. CT, furthermore, allows estimating the timing of ischemic damage.

  View details for DOI 10.1155/2014/895248

  View details for PubMedID 25247191

  View details for PubMedCentralID PMC4163450

• Model-based Iterative Reconstruction Compared to Adaptive Statistical Iterative Reconstruction and Filtered Back-projection in CT of the Kidneys and the Adjacent Retroperitoneum. Academic radiology Olcott, E. W., Shin, L. K., Sommer, G., Chan, I., Rosenberg, J., Molvin, F. L., Boas, F. E., Fleischmann, D. 2014; 21 (6): 774-784

  Abstract

  To prospectively evaluate the perceived image quality of model-based iterative reconstruction (MBIR) compared to adaptive statistical iterative reconstruction (ASIR) and filtered back-projection (FBP) in computed tomography (CT) of the kidneys and retroperitoneum.With investigational review board and Health Insurance Portability and Accountability Act compliance, 17 adults underwent 31 contrast-enhanced CT acquisitions at constant tube potential and current (range 30-300 mA). Each was reconstructed with MBIR, ASIR (50%), and FBP. Four reviewers scored each reconstruction's perceived image quality overall and the perceived image quality of seven imaging features that were selected by the authors as being relevant to imaging in the region and pertinent to the evaluation of high-quality diagnostic CT.MBIR perceived image quality scored superior to ASIR and FBP both overall (P < .001) and for observations of the retroperitoneal fascia (99.2%), corticomedullary differentiation (94.4%), renal hilar structures (96.8%), focal renal lesions (92.5%), and mitigation of streak artifact (100.0%; all, P < .001). MBIR achieved diagnostic overall perceived image quality with approximately half the radiation dose required by ASIR and FBP. The noise curve of MBIR was significantly lower and flatter (P < .001).Compared to ASIR and FBP, MBIR provides superior perceived image quality, both overall and for several specific imaging features, across a broad range of tube current levels, and requires approximately half the radiation dose to achieve diagnostic overall perceived image quality. Accordingly, MBIR should enable CT scanning with improved perceived image quality and/or reduced radiation exposure.

  View details for DOI 10.1016/j.acra.2014.02.012

  View details for PubMedID 24809318

• Debulking of the Anterolateral Quadrant of the Medial Gastrocnemius for Functional Popliteal Entrapment Syndrome in High-Performance Athletes Zayed, M., Fredericson, M., Fleischmann, D., Lee, J. T. MOSBY-ELSEVIER. 2014: 71S

  View details for DOI 10.1016/j.jvs.2014.03.158

  View details for Web of Science ID 000337258400148

• CT Angiography after 20 Years: A Transformation in Cardiovascular Disease Characterization Continues to Advance RADIOLOGY Rubin, G. D., Leipsic, J., Schoepf, U. J., Fleischmann, D., Napel, S. 2014; 271 (3): 633-652

  Abstract

  Through a marriage of spiral computed tomography (CT) and graphical volumetric image processing, CT angiography was born 20 years ago. Fueled by a series of technical innovations in CT and image processing, over the next 5-15 years, CT angiography toppled conventional angiography, the undisputed diagnostic reference standard for vascular disease for the prior 70 years, as the preferred modality for the diagnosis and characterization of most cardiovascular abnormalities. This review recounts the evolution of CT angiography from its development and early challenges to a maturing modality that has provided unique insights into cardiovascular disease characterization and management. Selected clinical challenges, which include acute aortic syndromes, peripheral vascular disease, aortic stent-graft and transcatheter aortic valve assessment, and coronary artery disease, are presented as contrasting examples of how CT angiography is changing our approach to cardiovascular disease diagnosis and management. Finally, the recently introduced capabilities for multispectral imaging, tissue perfusion imaging, and radiation dose reduction through iterative reconstruction are explored with consideration toward the continued refinement and advancement of CT angiography.

  View details for DOI 10.1148/radiol.14132232

  View details for Web of Science ID 000336894600004

  View details for PubMedID 24848958

• SINGLE-CENTER ACUTE AORTIC SYNDROME REGISTRY: A 10-YEAR EXPERIENCE OF "CLASS 3" LIMITED DISSECTION OF THE AORTA Chin, A. S., Kino, A., Berry, G., Rosenberg, J., Fischbein, M., Miller, D., Fleischmann, D. ELSEVIER SCIENCE INC. 2014: A1000

  View details for DOI 10.1016/S0735-1097(14)61000-7

  View details for Web of Science ID 000359579101658

• Dose reduction using a dynamic, piecewise-linear attenuator. Medical physics Hsieh, S. S., Fleischmann, D., Pelc, N. J. 2014; 41 (2): 021910-?

  Abstract

  The authors recently proposed a dynamic, prepatient x-ray attenuator capable of producing a piecewise-linear attenuation profile customized to each patient and viewing angle. This attenuator was intended to reduce scatter-to-primary ratio (SPR), dynamic range, and dose by redistributing flux. In this work the authors tested the ability of the attenuator to reduce dose and SPR in simulations.The authors selected four clinical applications, including routine full field-of-view scans of the thorax and abdomen, and targeted reconstruction tasks for an abdominal aortic aneurysm and the pancreas. Raw data were estimated by forward projection of the image volume datasets. The dynamic attenuator was controlled to reduce dose while maintaining peak variance by solving a convex optimization problem, assuminga priori knowledge of the patient anatomy. In targeted reconstruction tasks, the noise in specific regions was given increased weighting. A system with a standard attenuator (or "bowtie filter") was used as a reference, and used either convex optimized tube current modulation (TCM) or a standard TCM heuristic. The noise of the scan was determined analytically while the dose was estimated using Monte Carlo simulations. Scatter was also estimated using Monte Carlo simulations. The sensitivity of the dynamic attenuator to patient centering was also examined by shifting the abdomen in 2 cm intervals.Compared to a reference system with optimized TCM, use of the dynamic attenuator reduced dose by about 30% in routine scans and 50% in targeted scans. Compared to the TCM heuristics which are typically used withouta priori knowledge, the dose reduction is about 50% for routine scans. The dynamic attenuator gives the ability to redistribute noise and variance and produces more uniform noise profiles than systems with a conventional bowtie filter. The SPR was also modestly reduced by 10% in the thorax and 24% in the abdomen. Imaging with the dynamic attenuator was relatively insensitive to patient centering, showing a 17% increase in peak variance for a 6 cm shift of the abdomen, instead of an 82% increase in peak variance for a fixed bowtie filter.A dynamic prepatient x-ray attenuator consisting of multiple wedges is capable of achieving substantial dose reductions and modest SPR reductions.

  View details for DOI 10.1118/1.4862079

  View details for PubMedID 24506631

• CT Findings in Acute, Subacute, and Chronic Ischemic Colitis: Suggestions for Diagnosis BIOMED RESEARCH INTERNATIONAL Iacobellis, F., Berritto, D., Fleischmann, D., Gagliardi, G., Brillantino, A., Mazzei, M., Grassi, R. 2014

  View details for DOI 10.1155/2014/895248

  View details for Web of Science ID 000344290000001

• CT patterns of fungal pulmonary infections of the lung: Comparison of standard-dose and simulated low-dose CT (vol 81, pg 2860, 2012) EUROPEAN JOURNAL OF RADIOLOGY Christe, A., Lin, M. C., Yen, A. C., Hallett, R. L., Roychoudhury, K., Schmitzberger, F., Fleischmann, D., Leung, A. N., Rubin, G. D., Vock, P., Roos, J. E. 2013; 82 (11): 2067

  View details for DOI 10.1016/j.ejrad.2013.07.021

  View details for Web of Science ID 000325484600053

• Prospective optical motion correction for 3D time-of-flight angiography. Magnetic resonance in medicine Kopeinigg, D., Aksoy, M., Forman, C., Straka, M., Seaman, D., Rosenberg, J., Fleischmann, D., Hornegger, J., Bammer, R. 2013; 69 (6): 1623-1633

  Abstract

  Magnetic resonance angiograms are often nondiagnostic due to patient motion. In clinical practice, the available time to repeat motion-corrupted scans is very limited-especially in patients who suffer from acute cerebrovascular conditions. Here, the feasibility of an optical motion correction system to prospectively correct patient motion for 3D time-of-flight magnetic resonance angiography was investigated. Experiments were performed on five subjects with and without parallel imaging (SENSE R = 2) on a 1.5 T unit. Two human readers assessed the data and were in good agreement (kappa: 0.77). The results from this study indicate that the optical motion correction system greatly reduces motion artifacts when motion was present and did not impair the image quality in the absence of motion. Statistical analysis showed no significant difference between the (vendor-provided) SENSE and the nonaccelerated acquisitions. In conclusion, the optical motion correction system tested in this study has the potential to greatly improve 3D time-of-flight angiograms regardless of whether it is used with or without SENSE. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.

  View details for DOI 10.1002/mrm.24423

  View details for PubMedID 22887025

• Prospective optical motion correction for 3D time-of-flight angiography MAGNETIC RESONANCE IN MEDICINE Kopeinigg, D., Aksoy, M., Forman, C., Straka, M., Seaman, D., Rosenberg, J., Fleischmann, D., Hornegger, J., Bammer, R. 2013; 69 (6): 1623–33

  View details for DOI 10.1002/mrm.24423

  View details for Web of Science ID 000319074100013

• Pulmonary Circulation Imaging: Embryology and Normal Anatomy SEMINARS IN ULTRASOUND CT AND MRI Murillo, H., Cutalo, M. J., Jones, R. P., Lane, M. J., Fleischmann, D., Restrepo, C. S. 2012; 33 (6): 473-484

  Abstract

  This review focuses on the embryology and normal imaging anatomy of the pulmonary circulation, with emphasis on the major arterial and venous vasculature. The pulmonary circulation and parenchyma have a complex intertwined embryologic origin. Understanding the embryologic basis of normal pulmonary vasculature aids recognition of anomalies and visceral situs in the chest. Adaptive changes to congenital anomalies of the pulmonary arterial vasculature are used to contrast from normal and review associated temporal adaptive vascular and parenchymal changes.

  View details for DOI 10.1053/j.sult.2012.08.001

  View details for Web of Science ID 000312179300002

  View details for PubMedID 23168059

• A pictorial review of acute aortic syndrome: discriminating and overlapping features as revealed by ECG-gated multidetector-row CT angiography. Insights into imaging Ueda, T., Chin, A., Petrovitch, I., Fleischmann, D. 2012; 3 (6): 561-571

  Abstract

  The term "acute aortic syndrome" (AAS) encompasses a spectrum of life-threatening conditions characterized by acute aortic pain. AAS traditionally embraces three abnormalities including classic aortic dissection, intramural haematoma, and penetrating atherosclerotic ulcer. Although the underlying etiologies and conditions predisposing to AAS are diverse, the clinical features are indistinguishable.Multidetector-row computed tomography (CT) with electrocardiographic gating (ECG-gated MDCT) has greatly improved imaging of acute thoracic aortic diseases by virtually eliminating pulsation artifacts transmitted from cardiac motion and reveals subtle aortic abnormalities, which have been difficult to recognize by conventional non-gated CT.While these advances in imaging technology provide additional discriminating features of acute aortic diseases, they also reveal a range of overlapping features of these life-threatening conditions that not uncommonly are dynamic and evolving. These overlapping and transitional features may be a major source of misunderstanding, confusion, and controversy for diseases that cause AAS.In this pictorial review, we describe the discriminating and typical imaging features as revealed by modern ECG-gated MDCT angiography. In addition to the discriminating features, recognition of the overlapping and transitional features in AAS will allow a more comprehensive understanding of their underlying pathophysiologic conditions and their natural history, and may improve therapeutic management.• The superior visualization of ECG-gated CTA improves the diagnostic accuracy of acute aortic syndrome. • ECG-gated CTA provides discriminating features of underlying pathophysiologic conditions of AAS. • Also, recognition of the overlapping features in AAS will allow a more comprehensive understanding.

  View details for DOI 10.1007/s13244-012-0195-7

  View details for PubMedID 23129238

  View details for PubMedCentralID PMC3505562

• Feasibility of Pulmonary Interstitial Lymphography-guided Targeting in Stereotactic Ablative Radiation Therapy of Lung Tumors 54th Annual Meeting of the American-Society-for-Radiation-Oncology (ASTRO) Abelson, J. A., Kothary, N., Fleischmann, D., Hofmann, L., Kielar, K., Maxim, P., Le, Q., Diehn, M., Loo, B. W. ELSEVIER SCIENCE INC. 2012: S173–S173

  View details for Web of Science ID 000310542900432

• CT patterns of fungal pulmonary infections of the lung: Comparison of standard-dose and simulated low-dose CT EUROPEAN JOURNAL OF RADIOLOGY Christe, A., Lin, M. C., Yen, A. C., Hallett, R. L., Roychoudhury, K., Schmitzberger, F., Fleischmann, D., Leung, A. N., Rubin, G. D., Vock, P., Roos, J. E. 2012; 81 (10): 2860-2866

  Abstract

  To assess the effect of radiation dose reduction on the appearance and visual quantification of specific CT patterns of fungal infection in immuno-compromised patients.Raw data of thoracic CT scans (64 × 0.75 mm, 120 kVp, 300 reference mAs) from 41 consecutive patients with clinical suspicion of pulmonary fungal infection were collected. In 32 patients fungal infection could be proven (median age of 55.5 years, range 35-83). A total of 267 cuboids showing CT patterns of fungal infection and 27 cubes having no disease were reconstructed at the original and 6 simulated tube currents of 100, 40, 30, 20, 10, and 5 reference mAs. Eight specific fungal CT patterns were analyzed by three radiologists: 76 ground glass opacities, 42 ground glass nodules, 51 mixed, part solid, part ground glass nodules, 36 solid nodules, 5 lobulated nodules, 6 spiculated nodules, 14 cavitary nodules, and 37 foci of air-space disease. The standard of reference was a consensus subjective interpretation by experts whom were not readers in the study.The mean sensitivity and standard deviation for detecting pathological cuboids/disease using standard dose CT was 0.91 ± 0.07. Decreasing dose did not affect sensitivity significantly until the lowest dose level of 5 mAs (0.87 ± 0.10, p=0.012). Nodular pattern discrimination was impaired below the dose level of 30 reference mAs: specificity for fungal 'mixed nodules' decreased significantly at 20, 10 and 5 reference mAs (p<0.05). At lower dose levels, classification drifted from 'solid' to 'mixed nodule', although no lesion was missed.Our simulation data suggest that tube current levels can be reduced from 300 to 30 reference mAs without impairing the diagnostic information of specific CT patterns of pulmonary fungal infections.

  View details for DOI 10.1016/j.ejrad.2011.06.059

  View details for Web of Science ID 000308079700067

  View details for PubMedID 21835569

• Imaging of the Aorta: Embryology and Anatomy SEMINARS IN ULTRASOUND CT AND MRI Murillo, H., Lane, M. J., Punn, R., Fleischmann, D., Restrepo, C. S. 2012; 33 (3): 169-190

  Abstract

  This review focuses on the embryology and anatomy of the aorta with some imaging examples. Dividing the aorta by segments of unique function and embryogenesis facilitates organizing the group of potential anomalies encountered. A basic understanding of the embryologic development of the aorta and its major branches helps in understanding and recognizing typical and atypical anatomic findings. Diagnostic imaging of the aorta and its major branches can be accomplished by invasive and noninvasive methods, based on the clinical scenario and the age of the patient. In this review, computed tomography and magnetic resonance imaging examples are emphasized.

  View details for DOI 10.1053/j.sult.2012.01.013

  View details for Web of Science ID 000305094700002

  View details for PubMedID 22624964

• State-of-the-Art Computed Tomography Angiography of Acute Aortic Syndrome SEMINARS IN ULTRASOUND CT AND MRI Chin, A. S., Fleischmann, D. 2012; 33 (3): 222-234

  Abstract

  Acute aortic syndrome refers to a spectrum of acute life-threatening aortic abnormalities requiring prompt recognition and treatment. Although underlying pathologies are diverse, presenting signs and symptoms are often indistinguishable clinically, underscoring the role of imaging to make the correct diagnosis. Computed tomography (CT) angiography, a safe and accessible imaging modality, is paramount in accurately confirming or excluding critical aortic lesions, defining location and extent, and describing associated complications. Electrocardiographic gating further improves diagnostic precision of CT, providing motion-free 3- and 4-dimensional imaging of the entire aorta. This article reviews the imaging spectrum and state-of-the-art CT for patients presenting with acute aortic syndrome.

  View details for DOI 10.1053/j.sult.2012.01.003

  View details for Web of Science ID 000305094700005

  View details for PubMedID 22624967

• ACCURACY AND REPRODUCIBILITY OF CONTRAST ENHANCED AND NON-ENHANCED COMPUTED TOMOGRAPHY FOR PREDICTING THE ANGIOGRAPHIC DEPLOYMENT ANGLE IN TRANSCATHETER AORTIC VALVE REPLACEMENT (TAVR) 61st Annual Scientific Session and Expo of the American-College-of-Cardiology (ACC)/Conference on ACC-i2 with TCT Dao, C. N., Blake, T., Liang, D., Fischbein, M. P., Yeung, A., Fearon, W., Miller, D. C., Fleischmann, D. ELSEVIER SCIENCE INC. 2012: E1195–E1195

  View details for Web of Science ID 000302326701306

• COMPUTED TOMOGRAPHY BASED PREDICTION OF ANGIOGRAPHIC DEPLOYMENT ANGLES MAY REDUCE PROCEDURE TIME AND CONTRAST MEDIUM VOLUME FOR TRANSCATHETER AORTIC VALVE REPLACEMENT 61st Annual Scientific Session and Expo of the American-College-of-Cardiology (ACC)/Conference on ACC-i2 with TCT Fleischmann, D., Dao, C., Blake, T., Boas, F. E., Liang, D., Yeung, A., Fearon, W., Fischbein, M., Miller, D. C. ELSEVIER SCIENCE INC. 2012: E1199–E1199

  View details for Web of Science ID 000302326701310

• Cardiac Paraganglioma: Diagnostic and Surgical Challenges JOURNAL OF CARDIAC SURGERY Huo, J. L., Choi, J. C., DeLuna, A., Lee, D., Fleischmann, D., Berry, G. J., Deuse, T., Haddad, F. 2012; 27 (2): 178-182

  Abstract

  Primary cardiac paragangliomas are rare extra-adrenal tumors. Though they account for less than 1% of all primary cardiac tumors, they are considerable sources of morbidity and mortality. In this case review, we discuss the challenges associated with the diagnosis and management of cardiac paragangliomas.

  View details for DOI 10.1111/j.1540-8191.2011.01378.x

  View details for Web of Science ID 000302172800009

  View details for PubMedID 22273468

• Antiangiogenic and Radiation Therapy Early Effects on In Vivo Computed Tomography Perfusion Parameters in Human Colon Cancer Xenografts in Mice INVESTIGATIVE RADIOLOGY Ren, Y., Fleischmann, D., Foygel, K., Molvin, L., Lutz, A. M., Koong, A. C., Jeffrey, R. B., Tian, L., Willmann, J. K. 2012; 47 (1): 25-32

  Abstract

  To assess early treatment effects on computed tomography (CT) perfusion parameters after antiangiogenic and radiation therapy in subcutaneously implanted, human colon cancer xenografts in mice and to correlate in vivo CT perfusion parameters with ex vivo assays of tumor vascularity and hypoxia.Dynamic contrast-enhanced CT (perfusion CT, 129 mAs, 80 kV, 12 slices × 2.4 mm; 150 μL iodinated contrast agent injected at a rate of 1 mL/min intravenously) was performed in 100 subcutaneous human colon cancer xenografts on baseline day 0. Mice in group 1 (n=32) received a single dose of the antiangiogenic agent bevacizumab (10 mg/kg body weight), mice in group 2 (n=32) underwent a single radiation treatment (12 Gy), and mice in group 3 (n=32) remained untreated. On days 1, 3, 5, and 7 after treatment, 8 mice from each group underwent a second CT perfusion scan, respectively, after which tumors were excised for ex vivo analysis. Four mice were killed after baseline scanning on day 0 for ex vivo analysis. Blood flow (BF), blood volume (BV), and flow extraction product were calculated using the left ventricle as an arterial input function. Correlation of in vivo CT perfusion parameters with ex vivo microvessel density and extent of tumor hypoxia were assessed by immunofluorescence. Reproducibility of CT perfusion parameter measurements was calculated in an additional 8 tumor-bearing mice scanned twice within 5 hours with the same CT perfusion imaging protocol.The intraclass correlation coefficients for BF, BV, and flow extraction product from repeated CT perfusion scans were 0.93 (95% confidence interval: 0.78, 0.97), 0.88 (0.66, 0.95), and 0.88 (0.56, 0.95), respectively. Changes in perfusion parameters and tumor volumes over time were different between treatments. After bevacizumab treatment, all 3 perfusion parameters significantly decreased from day 1 (P ≤ 0.006) and remained significantly decreased until day 7 (P ≤ 0.008); tumor volume increased significantly only on day 7 (P=0.04). After radiation treatment, all 3 perfusion parameters decreased significantly on day 1 (P < 0.001); BF and flow extraction product increased again on day 3 and 5, although without reaching statistically significant difference; and tumor volumes did not change significantly at all time points (P ≥ 0.3). In the control group, all 3 perfusion parameters did not change significantly, whereas tumor volume increased significantly at all the time points, compared with baseline (P ≤ 0.04). Ex vivo immunofluorescent staining showed good correlation between all 3 perfusion parameters and microvessel density (ρ=0.71, 0.66, and 0.69 for BF, BV, and flow extraction product, respectively; P < 0.001). There was a trend toward negative correlation between extent of hypoxia and all 3 perfusion parameters (ρ=-0.53, -0.47, and -0.40 for BF, BV, and flow extraction product, respectively; P ≥ 0.05).CT perfusion allows a reproducible, noninvasive assessment of tumor vascularity in human colon cancer xenografts in mice. After antiangiogenic and radiation therapy, BF, BV, and flow extraction product significantly decrease and change faster than the tumor volume.

  View details for DOI 10.1097/RLI.0b013e31823a82f6

  View details for Web of Science ID 000298400100006

  View details for PubMedID 22178893

• Evaluation of a metal artifact reduction technique in tonsillar cancer delineation PRACTICAL RADIATION ONCOLOGY Abelson, J. A., Murphy, J. D., Wiegner, E. A., Abelson, D., Sandman, D. N., Boas, F., Hristov, D., Fleischmann, D., Daly, M. E., Chang, D. T., Loo, B. W., Hara, W., Le, Q. 2012; 2 (1): 27–34

  View details for DOI 10.1016/j.prro.2011.06.004

  View details for Web of Science ID 000422312600005

• Centerline Reformations of Complex Vascular Structures 5th IEEE Pacific Visualization Symposium Mistelbauer, G., Varchola, A., Bouzari, H., Starinsky, J., Koechl, A., Schernthaner, R., Fleischmann, D., Groeller, M. E., Sramek, M. IEEE COMPUTER SOC. 2012: 233–240

  View details for Web of Science ID 000316628200030

• Evaluation of a metal artifact reduction technique in tonsillar cancer delineation. Practical radiation oncology Abelson, J. A., Murphy, J. D., Wiegner, E. A., Abelson, D., Sandman, D. N., Boas, F. E., Hristov, D., Fleischmann, D., Daly, M. E., Chang, D. T., Loo, B. W., Hara, W., Le, Q. 2012; 2 (1): 27-34

  Abstract

  Metal artifacts can degrade computed tomographic (CT) simulation imaging and impair accurate delineation of tumors for radiation treatment planning purposes. We investigated a Digital Imaging and Communications in Medicine-based metal artifact reduction technique in tonsillar cancer delineation.Eight patients with significant artifact and tonsil cancer were evaluated. Each patient had a positron emission tomography (PET)-CT and a contrast-enhanced CT obtained at the same setting during radiotherapy simulation. The CTs were corrected for artifact using the metal deletion technique (MDT). Two radiation oncologists independently delineated primary gross tumor volumes (GTVs) for each patient on native (CTnonMDT), metal corrected (CTMDT), and reference standard (CTPET/nonMDT) imaging, 1 week apart. Mixed effects models were used to determine if differences among GTVs were statistically significant. Two diagnostic radiologists and 2 radiation oncologists independently qualitatively evaluated CTs for each patient. Ratings were on an ordinal scale from -3 to +3, denoting that CTMDT was markedly, moderately, or slightly worse or better than CTnonMDT. Scores were compared with a Wilcoxon signed-rank test.The GTVPET/nonMDT were significantly smaller than GTVnonMDT (P = .004) and trended to be smaller than GTVMDT (P = .084). The GTVnonMDT and GTVMDT were not significantly different (P = .93). There was no significant difference in the extent to which GTVnonMDT or GTVMDT encompassed GTVPET/nonMDT (P = .33). In the subjective assessment of image quality, CTMDT did not significantly outperform CTnonMDT. In the majority of cases, the observer rated the CTMDT equivalent to (53%) or slightly superior (41%) to the corresponding CTnonMDT.The MTD modified images did not produce GTVMDT that more closely reproduced GTVPET/nonMDT than did GTVnonMDT. Moreover, the MTD modified images were not judged to be significantly superior when compared to the uncorrected images in terms of subjective ability to visualize the tonsilar tumors. This study failed to demonstrate value of the adjunctive use of a CT corrected for artifacts in the tumor delineation process. Artifacts do make tumor delineation challenging, and further investigation of other body sites is warranted.

  View details for DOI 10.1016/j.prro.2011.06.004

  View details for PubMedID 24674033

• Coil Embolization of a Left Circumflex Feeder Branch in a Patient With a Mediastinal Paraganglioma JACC-CARDIOVASCULAR INTERVENTIONS Ho, M. Y., Fleischmann, D., Forrester, M. D., Lee, D. P. 2011; 4 (12): 1345-1346

  View details for DOI 10.1016/j.jcin.2011.06.021

  View details for PubMedID 22192376

• Targeting Lung Tumors in Image-Guided Stereotactic Ablative Radiotherapy using Pulmonary Interstitial Lymphography Abelson, J. A., Kothary, N., Fleischmann, D., Hofmann, L., Kielar, K. N., Maxim, P. G., Le, Q., Hara, W. Y., Diehn, M., Loo, B. W. ELSEVIER SCIENCE INC. 2011: S601–S601

  View details for Web of Science ID 000296411701313

• Three- and Four-Dimensional Imaging in Acute Aortic Syndrome DISEASES OF THE HEART AND CHEST, INCLUDING BREAST 2011-2014: DIAGNOSTIC IMAGING AND INTERVENTIONAL TECHNIQUES Fleischmann, D., Chin, A. S., Miller, D., Hodler, J., VonSchulthess, G. K., Zollikofer, C. L. 2011: 117–26

  View details for Web of Science ID 000291827800019

• Assessment of Aortic Annulus Diameter with Three-dimensional Transesophageal Echocardiography: Implications for Transcatheter Aortic Valve Implantation Dao, C., Fleischmann, D., Kratzert, B., Wong, J. K., McConnell, M. V., Liang, D. H. LIPPINCOTT WILLIAMS & WILKINS. 2010

  View details for Web of Science ID 000208231600304

• Incomplete Endograft Apposition to the Aortic Arch: Bird-Beak Configuration Increases Risk of Endoleak Formation after Thoracic Endovascular Aortic Repair RADIOLOGY Ueda, T., Fleischmann, D., Dake, M. D., Rubin, G. D., Sze, D. Y. 2010; 255 (2): 645-652

  Abstract

  To determine the clinical importance of the bird-beak configuration after thoracic endovascular aortic repair (TEVAR).The institutional review board approved this retrospective study and waived the requirement to obtain informed consent from patients. Sixty-four patients (40 men, 24 women; mean age, 64 years) who underwent TEVAR were evaluated. The treated diseases included dissection (n = 29), degenerative aneurysm (n = 13), acute traumatic transection (n = 8), pseudoaneurysm (n = 4), penetrating aortic ulcer (n = 6), intramural hematoma (n = 2), and mycotic aneurysm (n = 2). Bird-beak configuration, defined as the incomplete apposition of the proximal endograft with a wedge-shaped gap between the device and the aortic wall, was assessed with postprocedural CT angiography. The presence and length of the bird-beak configuration were compared with the formation of endoleaks and adverse clinical events.Endoleaks were detected in 26 (40%) of the 64 patients, including 14 with type Ia endoleak formation, one with type Ib endoleak formation, six with type II endoleak formation (from the left subclavian artery), two with type IIo endoleak formation (from other arteries), and three with type III endoleak formation. Bird-beak configuration was observed in 28 (44%) of 64 patients and correlated significantly with the risk of developing a type Ia or IIa endoleak (P < .01). Mean bird-beak length was significantly longer (P < .01) in patients with a type Ia or II endoleak (mean length, 14.3 and 13.9 mm, respectively) than in patients without endoleaks (mean length, 8.4 mm). Adverse events included early aortic-related death in three patients, additional treatment for endoleak in eight patients, and stent-graft collapse or infolding in six patients.Detection of bird-beak configuration is helpful in the prediction of adverse clinical events after TEVAR.

  View details for DOI 10.1148/radiol.10091468

  View details for Web of Science ID 000276976200040

  View details for PubMedID 20413775

• CT Angiography: Injection and Acquisition Technique RADIOLOGIC CLINICS OF NORTH AMERICA Fleischmann, D. 2010; 48 (2): 237-?

  Abstract

  CT scanner technology is continuously evolving, with scan times becoming shorter with each scanner generation. Achieving adequate arterial opacification synchronized with CT data acquisition is becoming increasingly difficult. A fundamental understanding of early arterial contrast medium dynamics is thus of utmost importance for the design of CT scanning and injection protocols for current and future cardiovascular CT applications. Arterial enhancement is primarily controlled by the iodine flux (injection flow rate) and the injection duration versus a patient's cardiac output and local downstream physiology. The technical capabilities of modern CT equipment require precise scan timing. Together with automated tube current modulation and weight-based injection protocols, both radiation exposure and contrast medium enhancement can be individualized.

  View details for DOI 10.1016/j.rcl.2010.02.002

  View details for Web of Science ID 000279865000003

  View details for PubMedID 20609872

• Embolization of a Symptomatic Systemic to Pulmonary (Right-to-left) Venous Shunt Caused by Fibrosing Mediastinitis and Superior Vena Caval Occlusion JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Sze, D. Y., Fleischmann, D., Ma, A. O., Price, E. A., McConnell, M. V. 2010; 21 (1): 140-143

  Abstract

  Paradoxical embolization can occur when a right-to-left shunt allows a venous thromboembolus to escape filtration by the lungs. Venous collateral pathways draining into the left heart incited by superior vena cava obstruction are a rare acquired right-to-left shunt. Herein, the authors report on a case of transient ischemic attack in a patient with vena caval occlusion secondary to histoplasmosis-related fibrosing mediastinitis, with subclavian vein thrombosis and a right-to-left extracardiac shunt diagnosed with echocardiography. Despite the complexity of the collateral network, this shunt was successfully eradicated with coil embolization.

  View details for DOI 10.1016/j.jvir.2009.09.022

  View details for PubMedID 20123198

• Infolding and collapse of thoracic endoprostheses: Manifestations and treatment options JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Sze, D. Y., Mitchell, R. S., Miller, D. C., Fleischmann, D., Frisoli, J. K., Kee, S. T., Verma, A., Sheehan, M. P., Dake, M. D. 2009; 138 (2): 324-333

  Abstract

  We sought to review the clinical sequelae and imaging manifestations of thoracic aortic endograft collapses and infoldings and to evaluate minimally invasive methods of repairing such collapses.Two hundred twenty-one Gore endografts (Excluder, TAG; W. L. Gore & Associates, Inc, Flagstaff, Ariz) were deployed in 145 patients for treatment of pathologies including aneurysms and pseudoaneurysms, dissections, penetrating ulcers, transections, fistulae, mycotic aneurysms, and neoplastic invasions in 6 different prospective trials at a single institution from 1997 to 2007. Device collapses and infoldings were analyzed retrospectively, including review of anatomic parameters, pathologies treated, device sizing and selection, clinical sequelae, methods of repair, and outcome.Six device collapses and infoldings were identified. Oversized devices placed into small-diameter aortas and imperfect proximal apposition to the lesser curvature were seen in all proximal collapses, affecting patients with transections and pseudoaneurysms. Infoldings in patients undergoing dissection represented incomplete initial expansion rather than delayed collapse. Delayed collapse occurred as many as 6 years after initial successful deployment, apparently as a result of changes in the aortic configuration from aneurysmal shrinkage. Clinical manifestations ranged from life-threatening ischemia to complete lack of symptoms. Collapses requiring therapy were remedied percutaneously by bare stenting or in one case by branch vessel embolization.Use of oversized devices in small aortas carries a risk of device failure by collapse, which can occur immediately or after years of delay. When clinically indicated, percutaneous repair can be effectively performed.

  View details for DOI 10.1016/j.jtcvs.2008.12.007

  View details for PubMedID 19619775

• Lower Extremity CT Angiography (CTA): Initial Evaluation of a Knowledge-Based Centerline Estimation Algorithm for Femoro-Popliteal Artery (FPA) Occlusions ACADEMIC RADIOLOGY Roos, J. E., Rakshe, T., Tran, D. N., Rosenberg, J., Straka, M., El-Helw, T., Sofilos, M. C., Napel, S., Fleischmann, D. 2009; 16 (6): 646-653

  Abstract

  Existing density- and gradient-based automated centerline-extraction algorithms fail in severely diseased or occluded arterial segments for the generation of curved planar reformations (CPRs). We aimed to quantitatively and qualitatively assess the precision of a knowledge-based centerline-extraction algorithm in patients with occluded femoro-popliteal artery (FPA).Computed tomography angiograms of 38 FPA occlusions (mean length 120 mm) were retrospectively identified. Reference centerlines were determined as the mean of eight manual expert readings. Each occlusion was also interpolated using a new knowledge-based algorithm (partial vector space projection [PVSP]), which uses shape information extracted from a separate database of 30 nondiseased FPAs. Precision of PVSP was quantified as the maximum departure error (MDE) from the standard of reference and the proportion of the interpolated centerlines remaining within an assumed vessel radius of 3 mm. Multiple regression method was used to determine the factors predicting the precision of the algorithm. CPR quality was independently assigned by two readers.The mean MDE (in mm) for occlusion lengths of <50 mm, 50-100 mm, 100-200 mm, and >200 mm was 0.95, 1.19, 1.40, and 2.25, for manual readings and 1.68, 2.90, 9.43, and 19.95 for PVSP, respectively. MDEs of the algorithm were completely contained within 3 mm of the assumed vessel radius in 20 of 38 occlusions. CPR quality was rated diagnostic by both readers in 23 of 38 occlusions.Shape-based centerline extraction of FPA occlusions in lower extremity CTA is feasible, and independent from local density and gradient information. PVSP centerline extraction allows interpolation of occlusions up to 100 mm within the variability of manually derived centerlines.

  View details for DOI 10.1016/j.acra.2009.01.015

  View details for Web of Science ID 000266210300002

  View details for PubMedID 19427978

• Value of MDCT Angiography in Developing Treatment Strategies for Critical Limb Ischemia AMERICAN JOURNAL OF ROENTGENOLOGY Schernthaner, R., Fleischmann, D., Stadler, A., Schernthaner, M., Lammer, J., Loewe, C. 2009; 192 (5): 1416-1424

  Abstract

  The purpose of this study was to assess the value of MDCT angiography in the development of strategies for the treatment of patients with critical limb ischemia.During a 12-month period, 150 patients were referred to our department for CT angiography of the peripheral arteries. All patients (n = 28) with clinical stage IV peripheral arterial occlusive disease were included in this retrospective study. The treatment reports, discharge summaries, and follow-up examinations were reviewed to ascertain the number of patients correctly treated on the basis of the CT angiographic findings.After CT angiography, endovascular treatment was indicated for eight patients, surgical revascularization for four patients, and a combined endovascular and surgical approach for two patients. That the correct treatment decision had been made in all 14 cases was confirmed on the basis of successful endovascular or surgical revascularization. In eight patients, medical treatment was indicated, and one patient underwent amputation at the level of the thigh. Five patients were referred for complementary digital subtraction angiography, but no additional findings were made. During follow-up, three of the original 28 patients were in grave general condition and died within 7 weeks after CT angiography. Thirteen patients needed no additional treatment during the follow-up period through January 2008. After a median treatment-free interval of 381 days, 12 patients underwent additional revascularization because of clinical progression of disease.MDCT angiographic findings lead to accurate recommendations for the management of critical limb ischemia. Thus CT angiography seems to be an important technique for the management of stage IV peripheral arterial occlusive disease in patients without absolute contraindications to CT angiography.

  View details for DOI 10.2214/AJR.08.1078

  View details for Web of Science ID 000265387300040

  View details for PubMedID 19380571

• Optimal Vascular and Parenchymal Contrast Enhancement: The Current State of the Art RADIOLOGIC CLINICS OF NORTH AMERICA Fleischmann, D., Kamaya, A. 2009; 47 (1): 13-?

  Abstract

  A fundamental understanding of early arterial and parenchymal contrast medium (CM) dynamics is the basis for the design of CT scanning and injection protocols for state-of-the-art cardiovascular and body CT applications. Although normal parenchymal enhancement is primarily controlled by the total iodine dose injected per body weight, arterial enhancement is controlled by the iodine flux, the injection duration, and cardiac output. The technical capabilities of modern CT equipment allow and require precise scan timing to synchronize data acquisition with the desired phase of vascular enhancement (for CTA) and parenchymal enhancement (for liver and pancreatic CT). Automated tube current modulation and weight-based injection protocols allow individual optimization of radiation exposure and reduce interindividual variability of CM enhancement.

  View details for DOI 10.1016/j.rcl.2008.10.009

  View details for Web of Science ID 000263843900003

  View details for PubMedID 19195531

• Contrast Medium Utilization INTEGRATED CARDIOTHORACIC IMAGING WITH MDCT Fleischmann, D., Lin, M. C., RemyJardin, M., Remy, J. 2009: 53–63

  View details for DOI 10.1007/978-3-540-72387-5_4

  View details for Web of Science ID 000266950700004

• Technical Advances in Cardiovascular Imaging SEMINARS IN THORACIC AND CARDIOVASCULAR SURGERY Fleischmann, D., Liang, D. H., Herfkens, R. J. 2008; 20 (4): 333–39

  View details for DOI 10.1053/j.semtcvs.2008.11.015

  View details for Web of Science ID 000416343300012

• Imaging of the Thoracic Aorta Before and After Stent-Graft Repair of Aneurysms and Dissections SEMINARS IN THORACIC AND CARDIOVASCULAR SURGERY Ueda, T., Fleischmann, D., Rubin, G. D., Dake, M. D., Sze, D. Y. 2008; 20 (4)

  View details for DOI 10.1053/j.semtcvs.2008.11.008

  View details for Web of Science ID 000416343300014

• Pre- and Postoperative Imaging of the Aortic Root for Valve-Sparing Aortic Root Repair (V-SARR) SEMINARS IN THORACIC AND CARDIOVASCULAR SURGERY Fleischmann, D., Liang, D. H., Mitchell, R., Miller, D. 2008; 20 (4): 365–73

  View details for DOI 10.1053/j.semtcvs.2008.11.009

  View details for Web of Science ID 000416343300016

• Acute Aortic Syndromes: New Insights from Electrocardiographically Gated Computed Tomography SEMINARS IN THORACIC AND CARDIOVASCULAR SURGERY Fleischmann, D., Mitchell, R., Miller, D. 2008; 20 (4): 340–47

  View details for DOI 10.1053/j.semtcvs.2008.11.011

  View details for Web of Science ID 000416343300013

• Surgically palliated double-inlet left ventricle with transposition of the great arteries mistaken for aortic aneurysm with dissection INTERNATIONAL JOURNAL OF CARDIOLOGY Gupta, A., Fleischmann, D., Murphy, D. J., Wu, J. C. 2008; 128 (2): E82-E84

  Abstract

  We report a 23-year-old male with history of double-inlet single ventricle with transposition of the great arteries who is s/p pulmonary artery banding, a Damus-Kaye-Stanzel anastomosis, and Fontan procedure during infancy and childhood who now presents with chest pain. A chest CTA at an outside hospital was thought concerning for the presence of a thoracic aortic aneurysm with dissection, prompting immediate transfer to our institution. However, repeat chest CTA at our institution revealed the predicted anastomoses based on his surgical procedures, which was misinterpreted as aortic aneurysm and dissection. An understanding of the physiology of his surgically repaired congenital heart disease is critical in interpreting his subsequent chest CTA and arriving at the appropriate clinical conclusion.

  View details for DOI 10.1016/j.ijcard.2007.04.165

  View details for Web of Science ID 000257950500043

  View details for PubMedID 17689761

• Unexpected findings during the anesthetic management of a patient with a cardiac paraganglioma JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA Soran, P. D., Akram, S., Mihm, F., Fleischmann, D., Reitz, B., van der Starre, P. 2008; 22 (4): 570-572

  View details for DOI 10.1053/j.jvca.2008.01.019

  View details for PubMedID 18662633

• Multidetector CT angiography in the assessment of peripheral arterial occlusive disease: accuracy in detecting the severity, number, and length of stenoses EUROPEAN RADIOLOGY Schernthaner, R., Stadler, A., Lomoschitz, F., Weber, M., Fleischmann, D., Lammer, J., Loewe, C. 2008; 18 (4): 665-671

  Abstract

  The purpose was to evaluate the accuracy of multidetector CT angiography (MD-CTA) in the morphologic assessment of peripheral arterial occlusive disease (PAOD) compared to digital subtraction angiography (DSA). Fifty consecutive patients referred for DSA of the peripheral arteries due to PAOD were prospectively included in this study and underwent 16-row MD-CTA prior to DSA. Maximum intensity projections and multipath curved planar reformations were created with a semi-automated toolbox. Twenty-one vascular segments were defined in each leg and compared to DSA findings with regard to gradation, length, and number of lesions. Mean sensitivity and specificity in the detection of significant stenoses (over 70%) were 100% and 99.5% in the iliac arteries, 97.4% and 99.0% in the femoro-popliteal arteries, and 98.3% and 99.8% in the infrapopliteal arteries, respectively. High kappa values for exact stenoses gradation (0.74-1), lesion length (0.74-1), and number of lesions (0.71-1) were reached by MD-CTA, indicating high agreement with DSA. Non-invasive MD-CTA is an accurate tool for the assessment of all treatment-relevant morphologic information of PAOD (gradation, length, and number of stenoses) compared to DSA.

  View details for DOI 10.1007/s00330-007-0822-8

  View details for Web of Science ID 000254235900003

  View details for PubMedID 18094974

• The aortopathy of bicuspid aortic valve disease has distinctive patterns and usually involves the transverse aortic arch 33rd Annual Meeting of the Western-Thoracic-Surgical-Association Fazel, S. S., Mallidi, H. R., Lee, R. S., Sheehan, M. P., Liang, D., Fleischman, D., Herfkens, R., Mitchell, S., Miller, D. C. MOSBY-ELSEVIER. 2008: 901–U54

  Abstract

  Bicuspid aortic valves are associated with a poorly characterized connective tissue disorder that predisposes to aortic catastrophes. Because no criterion exists dictating the appropriate extent of aortic resection in aneurysmal disease of the bicuspid aortic valve, we studied the patterns of aortic dilation in this population.Sixty-four patients with bicuspid aortic valves who underwent computed tomographic or magnetic resonance angiography and echocardiography were retrospectively identified between January 2002 and March 2006. Orthonormal 2-dimensional or 3-dimensional aortic diameters were measured at 10 levels. Agglomerative hierarchic clustering with centered correlation distance measurements and complete linkage analysis was used to detect distinct patterns of aortic dilatation.Mean aortic diameter was 28.1 +/- 0.7 mm at the annulus and 21.7 +/- 0.4 mm at the diaphragmatic hiatus. The aorta was largest in the tubular ascending aorta (45.9 +/- 1.0 mm). Compared with the descending aorta, the transverse aortic arch was also dilated (P < .01). Cluster analysis showed 4 patterns of aortic dilatation: cluster I, aortic root alone (n = 8, 13%); cluster II, tubular ascending aorta alone (n = 9, 14%); cluster III, tubular portion and transverse arch (n = 18, 28%); and, cluster IV, aortic root and tubular portion with tapering across the transverse arch (n = 29, 45%).Distinct patterns of aortic dilatation in patients with bicuspid aortic valves call for an individualized degree of aortic replacement to minimize late aortic complications and reoperation. Patients in clusters III and IV should have transverse arch replacement (plus concomitant root replacement in cluster IV). Patients in cluster I should undergo complete aortic root replacement, whereas in patients in cluster II supracommissural ascending aortic grafting is adequate.

  View details for DOI 10.1016/j.jtcvs.2008.01.022

  View details for PubMedID 18374778

• Pre- and postoperative imaging of the aortic root for valve-sparing aortic root repair (V-SARR). Seminars in thoracic and cardiovascular surgery Fleischmann, D., Liang, D. H., Mitchell, R. S., Miller, D. C. 2008; 20 (4): 365-373

  Abstract

  Valve-sparing aortic root repair (V-SARR) using the David reimplantation method is an increasingly popular alternative to composite valve graft aortic root replacement in patients with aortic root aneurysms or dissections who wish to avoid anticoagulation. Computed tomography (CT) with retrospective electrocardiograph (ECG)-gating has become routine before and following V-SARR at Stanford. CT allows accurate measurement of aortic dimensions and provides unprecedented three-dimensional (3D) images of the sinuses, the aortic valve cusps, and coronary arteries in patients with the Marfan syndrome (MFS), with a bicuspid aortic valve (BAV), or other aortic diseases. This helps the surgeon to conceptualize the size of the aortic grafts required and how much reduction is necessary proximally (aortic annulus) and distally. These maneuvers are used to reduce the aortic annular diameter (when necessary) and replace the sinuses and ascending aorta (T. David-V, Stanford modification V-SARR). Postoperative ECG-gated CT confirms the reconstructed geometry and reliably detects coronary or other anastomotic problems.

  View details for DOI 10.1053/j.semtcvs.2008.11.009

  View details for PubMedID 19251178

• Advances in imaging of cardiovascular diseases: introduction. Seminars in thoracic and cardiovascular surgery Fleischmann, D., Liang, D. H., Miller, D. C. 2008; 20 (4): 332-?

  View details for DOI 10.1053/j.semtcvs.2008.12.002

  View details for PubMedID 19251173

• Imaging of the thoracic aorta before and after stent-graft repair of aneurysms and dissections. Seminars in thoracic and cardiovascular surgery Ueda, T., Fleischmann, D., Rubin, G. D., Dake, M. D., Sze, D. Y. 2008; 20 (4): 348-357

  Abstract

  Thoracic endovascular aortic repair (TEVAR) has become widely accepted as an important option for treatment of thoracic aortic diseases. Cross-sectional radiologic imaging plays a crucial role for evaluating a patient's candidacy for planning of the intervention and for assessment of postprocedural results and complications of TEVAR. Recent advances in imaging technologies, in part inspired by advances in stent-graft technology, have drastically changed the character and role of pre- and postprocedural imaging. Three-dimensional (3D) datasets acquired quickly by multidetector computed tomography (MDCT), angiography, or magnetic resonance angiography (MRA) allow multiplanar reformations and 3D viewing, as well as quantitative assessment of vessel lumens, walls, and surroundings. Catheter angiography, in contrast, is performed intraoperatively almost exclusively, and is no longer the gold standard for diagnostic or planning purposes. This article reviews state-of-the-art pre- and postprocedural imaging for TEVAR, especially focusing on the role of MDCT angiography.

  View details for DOI 10.1053/j.semtcvs.2008.11.008

  View details for PubMedID 19251176

• Technical advances in cardiovascular imaging. Seminars in thoracic and cardiovascular surgery Fleischmann, D., Liang, D. H., Herfkens, R. J. 2008; 20 (4): 333-339

  Abstract

  Cardiovascular imaging technology is continuously evolving and provides an increasing array of tests to evaluate cardiovascular morphology and function. A basic understanding of imaging technology is helpful to select the best modality to answer a specific clinical question. This article provides a brief overview of recent technical developments in computed tomography (CT), magnetic resonance (MR), and echocardiography, which have increased our diagnostic understanding and may modulate treatment planning of patients with cardiovascular diseases: electrocardiographically (ECG)-gated CT, 4D-flow magnetic resonance imaging (MRI), and three-dimensional (3D) echocardiography.

  View details for DOI 10.1053/j.semtcvs.2008.11.015

  View details for PubMedID 19251174

• Acute aortic syndromes: new insights from electrocardiographically gated computed tomography. Seminars in thoracic and cardiovascular surgery Fleischmann, D., Mitchell, R. S., Miller, D. C. 2008; 20 (4): 340-347

  Abstract

  The development of retrospective electrocardiographic (ECG)-gating has proved to be a diagnostic and therapeutic boon for computed tomography (CT) imaging of patients with acute thoracic aortic diseases, such as aortic dissection/intramural hematoma (AD/IMH), penetrating atherosclerotic ulcer (APU), and ruptured/leaking aneurysm. The notorious pulsation motion artifacts in the ascending aorta confounding regular CT scanning can be eliminated, and involvement of the sinuses of Valsalva, the valve cusps, the aortic annulus, and the coronary arteries in aortic dissection can be clearly depicted or excluded. Motion-free images also allow reliable identification of the site of the primary intimal tear, the location, and extent of the intimomedial flap, and branch artery involvement. ECG-gated CTA also allows the detection of more subtle lesions and variants of aortic dissection, which may ultimately expand our understanding of these complex, life-threatening disorders.

  View details for DOI 10.1053/j.semtcvs.2008.11.011

  View details for PubMedID 19251175

• Effect of MDCT angiographic findings on the management of intermittent claudication AMERICAN JOURNAL OF ROENTGENOLOGY Schernthaner, R., Fleischmann, D., Lomoschitz, F., Stadler, A., Lammer, J., Loewe, C. 2007; 189 (5): 1215-1222

  Abstract

  The purpose of this study was to assess the reliability of treatment decisions based on MDCT angiographic findings of stage IIb peripheral arterial occlusive disease (PAOD).Fifty-eight patients with stage IIb PAOD underwent CT angiography of the abdominal aorta and runoff vessels for further treatment planning. Treatment reports, discharge summaries, and follow-up examinations were reviewed to determine the number of treatments correctly planned on the basis of CT angiographic findings.On the basis of CT angiographic findings, endovascular treatment was indicated for 18 patients, surgical revascularization for nine patients, and a combined endovascular and surgical approach for two patients. Conservative treatment was indicated for 29 patients. On the basis of successful revascularization, the correctness of the treatment decision was confirmed in all but one patient (n = 28). The treatment plan was modified for one patient referred for surgical revascularization. In that patient, stenosis of the common femoral artery had been overlooked on CT angiography. Patients for whom conservative management was indicated on the basis of CT angiographic findings (n = 29) had a mean follow-up period of 501 days without needing revascularization treatment. This result was defined as indirect confirmation of the accuracy of the decision made with CT angiography.The findings on MDCT angiography led to correct treatment recommendations for patients with claudication. Thus, CT angiography should be used in the management of PAOD.

  View details for DOI 10.2214/AJR.07.2054

  View details for Web of Science ID 000250518500033

  View details for PubMedID 17954664

• Rapid aneurysmal degeneration of a Stanford type B aortic dissection in a patient with Loeys-Dietz syndrome JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Lee, R. S., Fazel, S., Schwarze, U., Fleischmann, D., Berry, G. J., Liang, D., Miller, D. C., Mitchell, R. S. 2007; 134 (1): 242-U32

  View details for DOI 10.1016/j.jtcvs.2007.03.004

  View details for PubMedID 17599521

• Clinical 3D and 4D imaging of the thoracic aorta 39th International Diagnostic Course Fleischmann, D., Miller, D. C. SPRINGER-VERLAG ITALIA. 2007: 119–130

  View details for Web of Science ID 000246436000020

• Tools of the trade for CTA: MDCT scanners and contrast medium injection protocols. Techniques in vascular and interventional radiology Hallett, R. L., Fleischmann, D. 2006; 9 (4): 134-142

  Abstract

  The introduction of multi-detector row computed tomography (MDCT) scanners in 1998 ushered in new advances in CT angiography (CTA). The subsequent expansion of MDCT scanner capabilities, coupled with advances in understanding of contrast medium (CM) dynamics, has further improved the clinical availability and consistency of CTA. We will review recent advances in CT scanner technology and discuss early CM dynamics. Specifically, we describe an approach tailored to the available scanner technology and to patient size aimed at providing consistently robust CTA studies across all vascular territories. A rational method to design combined CTA scan/injection protocols to facilitate this goal will be described. Our current experience with a simplified protocol for CTA with 64-MDCT will also be explained.

  View details for PubMedID 17709077

• Giant coronary aneurysms in heart transplantation: an unusual presentation of cardiac allograft vasculopathy JOURNAL OF HEART AND LUNG TRANSPLANTATION Haddad, F., Perez, M., Fleischmann, D., Valantine, H., Hunt, S. A. 2006; 25 (11): 1367-1370

  Abstract

  Cardiac allograft vasculopathy is a leading cause of death during long-term follow-up of heart transplant recipients. We report 2 cases of cardiac allograft vasculopathy associated with giant coronary aneurysms. To our knowledge, these are the first reported cases of spontaneous giant coronary aneurysms in heart transplant recipients.

  View details for DOI 10.1016/j.healun.2006.07.006

  View details for Web of Science ID 000242222100015

  View details for PubMedID 17097503

• Peripheral CT angiography for interventional treatment planning. European radiology Fleischmann, D., Lammer, J. 2006; 16: M58-64

  Abstract

  Lower extremity CT angiography (CTA) has evolved into a very effective, widely available and robust imaging modality for patients with peripheral arterial occlusive disease (PAOD). In this article we briefly review the acquisition and contrast administration techniques for 4- through 64-channel peripheral CTA. Visualization of atherosclerotic disease with CTA in general requires 'angiography-like' 3D images (such as volume rendered or maximum intensity projection images), but-notably in the presence of vessel wall calcifications and stents-cross-sectional views (such as curved planar reformations, CPR) are also required to accurately assess the flow lumen of the aorta down to the pedal arteries. Adequate visualization and mapping of atherosclerotic lesions in patients with PAOD is not only a prerequisite for generating a dictated report, but more importantly, standardized postprocessed images are the key to communicating the findings to the treating physician, and they also serve as a treatment planning tool. Treatment decisions (surgical versus transluminal revascularization, or conservative treatment), and percutaneous treatment planning (access site, antegrade versus retrograde puncture) can be made in the majority of patients with PAOD based on lower extremity CT angiograms.

  View details for PubMedID 18655268

• Unusual case of late thoracic stent graft failure after cardioversion ANNALS OF THORACIC SURGERY Caffarelli, A. D., BANOVAC, F., Cheung, S. C., Fleischmann, D., Mitchell, R. S. 2006; 81 (5): 1875-1877

  Abstract

  We report the unusual case of successful endovascular exclusion of a thoracic aortic aneurysm with subsequent thoracic aortic aneurysm reduction, and development of an interval, acute type III endoleak after cardioversion 5 years after stent graft deployment.

  View details for DOI 10.1016/j.athoracsur.2005.04.087

  View details for Web of Science ID 000237001700052

  View details for PubMedID 16631691

• PTA versus carbofilm-coated stents in infrapopliteal arteries: Pilot study CARDIOVASCULAR AND INTERVENTIONAL RADIOLOGY Rand, T., Basile, A., Cejna, M., Fleischmann, D., Funovics, M., Gschwendtner, M., Haumer, M., Von Katzler, I., Kettenbach, J., Lomoschitz, F., Luft, C., Minar, E., Schneider, B., Schoder, M., Lammer, J. 2006; 29 (1): 29-38

  Abstract

  To determine the primary success and short-term patency of stent application as a primary treatment modality for high-grade lesions of the infrapopliteal arteries compared with treatment with percutaneous transluminal angioplasty (PTA) in critical limb ischemia in a randomized prospective study.Endovascular therapy was performed on 95 lesions in 51 patients (mean age 72.0 years, range 47-80 years) who presented clinically with Fontaine stages III and IV. One patient underwent treatment in both limbs. After angiographic lesion identification, patients were randomized for treatment by PTA (53 lesions in 27 patients) or stent application (42 lesions in 24 patients). Follow-up by clinical investigation and conventional angiography or spiral CT angiography was performed in 37 patients (57 lesions) 6 to 12 months after the procedure, or when clinically indicated. Evaluation was performed by two observers, double-blinded, with thresholds for lesion restenosis of 50% and 70%. Statistical evaluation was performed on a lesion basis by Kaplan-Meier estimated probability rates, and log-rank and Wilcoxon tests. The primary endpoint was the angiographic patency rate of treated lesions.The inter-reader agreement was high (kappa = 0.82). For the stent group the cumulative primary patency at 6 months was 83.7% at the 70% restenosis threshold, and 79.7% at the 50% restenosis threshold. For PTA, the primary patency at 6 months was 61.1% at the 70% restenosis threshold and 45.6% at the 50% restenosis threshold. Both results were statistically significant (p < 0.05).Infrapopliteal stent application is an effective treatment modality for high-grade lesions in chronic critical limb ischemia. Compared with PTA, higher patency rates can be expected after 6 months.

  View details for DOI 10.1007/s00270-005-0276-9

  View details for Web of Science ID 000234728900006

  View details for PubMedID 16252079

• CT angiography of peripheral arterial disease JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Fleischmann, D., Hallett, R. L., Rubin, G. D. 2006; 17 (1): 3-26

  Abstract

  Lower-extremity computed tomographic (CT) angiography (ie, peripheral CT angiography) is increasingly used to evaluate patients with peripheral arterial disease. It is therefore increasingly important for all vascular specialists to become familiar with the strengths and limitations of this new technique. The aims of this review are to explain the principles of scanning and injection technique for a wide range of CT scanners, to explain and illustrate the properties of current image postprocessing tools for effective visualization and treatment planning, and to provide an overview of current clinical applications of peripheral CT angiography.

  View details for DOI 10.1097/01.RVI.0000191361.02857.DE

  View details for Web of Science ID 000236517800002

  View details for PubMedID 16415129

• Peripheral CT angiography for interventional treatment planning European Radiology Fleischmann D, Lammer J 2006; 16 Supp.7: M58-M64
• How to design injection protocols for multiple detector-row CT angiography (MDCTA) EUROPEAN RADIOLOGY Fleischmann, D. 2005; 15: E60-E65

  Abstract

  The basis of the development of optimal injection protocols for multiple detector-row CT-angiography is knowledge of the physiological and pharmacokinetic principles of arterial enhancement. This article reviews the key rules of early arterial contrast medium dynamics: (1) Arterial enhancement is directly proportional to the iodine administration rate (iodine flux), and can be controlled by the injection flow rate and the iodine concentration of the contrast medium; (2) Arterial enhancement continuously increases over time with longer injection durations, due to the cumulative effects of bolus broadening and recirculation; (3) The strength of an individual's enhancement response to intravenously administered CM depends primarily on the patient's cardiac output and correlates inversely with body weight. In CTA, any of the following strategies can be employed alone, or in combination, to achieve adequate arterial enhancement in spite of short acquisition times: Increasing the injection rate, using higher concentration CM or increasing the injection duration (and scanning delay) relative to the scan time. Both injection volumes and flow rates should be adjusted to body weight, at least for patients < or =60 kg and > or =90kg BW. Rationally designed injection protocols based on physiological concepts allow optimal CM utilisation and take full advantage of the technical capabilities offered by modern MDCT scanners.

  View details for DOI 10.1007/s10406-005-0166-x

  View details for Web of Science ID 000235718500007

  View details for PubMedID 18637231

• Angiographic imaging of the lower extremities with multidetector CT RADIOLOGIC CLINICS OF NORTH AMERICA Hiatt, M. D., Fleischmann, D., Hellinger, J. C., Rubin, G. D. 2005; 43 (6): 1119-?

  Abstract

  Multidetector CT (MDCT) has improved imaging of the arteries in the lower extremities. The main advantages of this novel technology are the exceptionally fast scan times, high spatial resolution, increased anatomic coverage, and capability to generate high-quality multiplanar reformations and three-dimensional (3-D) renderings from raw data that can be reprocessed easily and quickly. The applications of MDCT in imaging the lower extremities are multiple and varied. They include the evaluation of peripheral arterial occlusive and aneurysmal disease, the patency and integrity of bypass grafts, and arterial injury owing to trauma. This article describes the techniques of lower extremity MDCT angiography and its use in a few clinical applications.

  View details for DOI 10.1016/j.rcl.2005.08.008

  View details for Web of Science ID 000233251800011

  View details for PubMedID 16253665

• Detection of endograft fractures with multidetector row computed tomography JOURNAL OF VASCULAR SURGERY Roos, J. E., Hellinger, J. C., Hallet, R., Fleischmann, D., Zarins, C. K., Rubin, G. D. 2005; 42 (5): 1002-1006

  Abstract

  Delayed endograft metallic strut failures detected in vivo with multidetector row computed tomography (MDCT) are reported in two patients who underwent endovascular abdominal aortic aneurysm repair with AneuRx and Talent endografts. In both instances, nitinol fractures were associated with proximal migration and type I endoleak. In both cases, the metallic strut fractures were detected with transverse sections from 16-channel MDCT angiograms and confirmed by using volume rendering. These cases highlight the previously unreported ability of thin-section, high-resolution MDCT angiography to detect endograft strut fractures.

  View details for DOI 10.1016/j.jvs.2005.07.009

  View details for Web of Science ID 000233090000038

  View details for PubMedID 16275461

• CT angiography of pulmonary artery aneurysms in Hughes-Stovin syndrome AMERICAN JOURNAL OF ROENTGENOLOGY Ketchum, E. S., Zamanian, R. T., Fleischmann, D. 2005; 185 (2): 330-332

  View details for PubMedID 16037501

• Multidetector CT imaging thoracoabdominal of aortic aneurysms 105th Annual Meeting of the American-Roentgen-Ray-Society Kamaya, A., Cheung, S., Miller, D. C., Hellinger, J. C., Hallett, R., Fleischmann, D. AMER ROENTGEN RAY SOC. 2005: 134–34

  View details for Web of Science ID 000228717800566

• Multidetector-row CT angiography (MDCTA) of the upper extremity: Technique and applications Poplaw, S., Hellinger, J. C., Hallett, R., Hiatt, M., Fleischmann, D., Rubin, G. D. AMER ROENTGEN RAY SOC. 2005: 134

  View details for Web of Science ID 000228717800564

• Computed tomography angiography - State-of-the-art imaging using multidetector-row technology Conference on Advances in Multi-Detector CT Napoli, A., Fleischmann, D., Chan, F. P., Catalano, C., Hellinger, J. C., Passariello, R., Rubin, G. D. LIPPINCOTT WILLIAMS & WILKINS. 2004: S32–S45

  Abstract

  Multidetector-row computed tomography (MDCT) is an essential diagnostic modality for many clinical algorithms. This is particularly true with regard to the evaluation of cardiovascular disease. As a result of increased image acquisition speed, improved spatial resolution, and greater scan volume, MDCT angiography (computed tomography angiography [CTA]) has become an excellent noninvasive imaging technique, replacing intra-arterial digital subtraction angiography for most vascular territories. The clinical success of CTA depends on precise synchronization of image acquisition with optimal vascular enhancement. As technology continuously evolves, however, this task can be challenging. It remains important to have a fundamental knowledge of the principles behind technical parameters and contrast medium administration. This article reviews these essential principles, followed by an overview of current clinical applications.

  View details for Web of Science ID 000222968800008

  View details for PubMedID 15258492

• Successful treatment of a Stanford type A dissection by percutaneous placement of a covered stent graft in the ascending aorta JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Ihnken, K., Sze, D., Dake, M. D., Fleischmann, D., van der Starre, P., Robbins, R. 2004; 127 (6): 1808-1810

  View details for DOI 10.1016/j.jteves.2003.12.019

  View details for Web of Science ID 000221895700036

  View details for PubMedID 15173740

• Value of negative spiral CT angiography in patients with suspected acute PE: analysis of PE occurrence and outcome EUROPEAN RADIOLOGY Krestan, C. R., Klein, N., Fleischmann, D., Kaneider, A., Novotny, C., Kreuzer, S., Riedl, C., Minar, E., Janata, K., Herold, C. J. 2004; 14 (1): 93-98

  Abstract

  The aim of this study was to analyze pulmonary embolism (PE) occurrence and retrospective clinical outcome in patients with clinically suspected acute PE and a negative spiral CT angiography (SCTA) of the pulmonary arteries. Within a 35-month period, 485 consecutive patients with clinical symptoms of acute PE underwent SCTA of the pulmonary arteries. Patients with a negative SCTA and without anticoagulation treatment were followed-up and formed the study group. Patient outcome and recurrence of PE was evaluated retrospectively during a period of 6 months after the initial SCTA, and included a review of computerized patient records, and interviews with physicians and patients. Patients were asked to fill out a questionnaire concerning all relevant questions about their medical history and clinical course during the follow-up period. Special attention was focused on symptoms indicating recurrent PE, as well as later confirmation and therapy of PE. Of the 485 patients, 325 patients (67%) had a negative scan, 134 (27.6%) had radiological signs of PE, and 26 (5.4%) had an indeterminant result. Of 325 patients with a negative scan, 269 (83%) were available for follow-up. The main reasons for loss to follow-up were change of address, name, or phone number, or non-resident patients who left abroad. Of 269 patients available for follow-up, 49 patients (18.2% of 269) received anticoagulant treatment because of prior or recent deep venous thrombosis (32.6%) or a history of PE (34.7%), cardiovascular disease (18.4%), high clinical probability (8.2%), positive ventilation-perfusion scan (4.2%), and elevated D-dimer test (2%). The remaining 220 patients, who did not receive anticoagulant medication, formed the study group. Of this study group, 1 patient died from myocardial infarction 6 weeks after the initial SCTA, and the postmortem examination also detected multiple peripheral emboli in both lungs ( p=0.45%; 0.01-2.5, 95% confidence interval). The PE did not occur in any other patient. In patients with suspected PE and negative SCTA without anticoagulant therapy, the risk of recurrent PE in this study was less than 1% and similar to that in patients after a negative pulmonary angiogram. Therefore, we conclude that patients can be managed safely without anticoagulation therapy; however, this approach may not be appropriate for critically ill patients and those with persistent high clinical suspicion of acute PE.

  View details for DOI 10.1007/s00330-003-2016-3

  View details for Web of Science ID 000188208500011

  View details for PubMedID 12942280

• Assessment for traumatic extremity vascular injury with multidetector-row CT angiography: Clinical experience in 35 exams Hellinger, J. C., Williamson, E., Fleischmann, D., Rubin, G. D. AMER ROENTGEN RAY SOC. 2004: 79

  View details for Web of Science ID 000220593100303

• Non-linear model fitting to parameterize diseased blood vessels IEEE Visualization 2004 Conference La Cruz, A., Straka, M., Kochl, A., Sramek, M., Groller, E., Fleischmann, D. IEEE. 2004: 393–400

  View details for Web of Science ID 000225187500050

• The VesselGlyph: Focus & context visualization in CT-angiography IEEE Visualization 2004 Conference Straka, M., Cervenansky, M., La Cruz, A., Kochl, A., Sramek, M., Groller, E., Fleischmann, D. IEEE. 2004: 385–392

  View details for Web of Science ID 000225187500049

• Use of high-concentration contrast media in multi pie-detector-row CT: principles and rationale 4th Bracco Symposium on Multidetector-Row Computed Tomography Fleischmann, D. SPRINGER. 2003: M14–M20

  Abstract

  Contrast-medium-enhanced multiple-detector-row CT (MDCT) is a powerful technique for vascular and hepatic imaging. With increasingly faster acquisition speeds, which have become possible with latest 8- and 16-channel scanner systems, contrast medium delivery is becoming increasingly difficult. This article reviews the pharmacokinetic and physiologic principles of vascular and hepatic enhancement following the intravenous injection of iodinated contrast medium. The effects of user-selectable injection parameters, such as the injection rate, the injection duration, and the contrast medium concentration on arterial and parenchymal enhancement are elucidated. Equipped with this knowledge, rational injection strategies for CT angiographic protocols for scanners with different acquisition speeds are derived. Furthermore, injection and timing protocols, optimized for hepatic MDCT during the early arterial, late arterial, and parenchymal phases, are developed.

  View details for Web of Science ID 000188877800004

  View details for PubMedID 14989606

• MDCT of renal and mesenteric vessels 4th Bracco Symposium on Multidetector-Row Computed Tomography Fleischmann, D. SPRINGER. 2003: M94–M101

  Abstract

  Computed tomography angiography (CTA) with multiple detector-row CT (MDCT) has evolved into an established technique for non-invasive imaging of renal and mesenteric vessels. With adequate selection of acquisition parameters (thin collimation) high spatial-resolution volumetric data sets for subsequent 2D and 3D reformation can be acquired. Contrast medium (CM) injection parameters need to be adjusted to the acquisition speed of the scanners. Whereas fast acquisitions allow a reduction of total CM volume in the setting of CTA, this is not the case when CTA is combined with a second-phase abdominal MDCT acquisition for parenchymal (e.g., hepatic) imaging. Renal CTA is an accurate and reliable test for visualizing vascular anatomy and renal artery stenosis, and therefore a viable alternative to MRA in the assessment of patients with renovascular hypertension and in potential living related renal donors. CTA, combined with abdominal/parenchymal MDCT is a first-line diagnostic test in patients with suspected abdominal vascular emergencies, such as acute mesenteric ischemia, and an excellent tool to assess a wide variety of vascular abnormalities of the abdominal viscera.

  View details for Web of Science ID 000188877800015

  View details for PubMedID 14989617

• Future prospects in MDCT imaging 4th Bracco Symposium on Multidetector-Row Computed Tomography Fleischmann, D. SPRINGER. 2003: M127–M128

  View details for Web of Science ID 000188877800020

  View details for PubMedID 14989622

• High-concentration contrast media in MDCT angiography: principles and rationale EUROPEAN RADIOLOGY Fleischmann, D. 2003; 13: N39-N43

  View details for Web of Science ID 000188320400005

  View details for PubMedID 15015879

• Use of high concentration contrast media: principles and rationale - vascular district 3rd Bracco Symposium on MDCT Fleischmann, D. ELSEVIER IRELAND LTD. 2003: S88–S93

  Abstract

  Optimal contrast medium delivery remains a crucial issue in CT angiography and it will become even more critical with continuously evolving, faster CT scanner technology. This review article first explains the fundamentals of arterial enhancement using mathematical models of early contrast medium dynamics. The relationship of contrast medium volume, injection flow rates and injection duration are explicitly illustrated. Next, current techniques of contrast medium application are reviewed, with particular attention to methods of accurate timing of the scanning delay (test-bolus and automated bolus triggering), tools for automated saline-flushing of the veins (double-syringe power injectors) and the use of high-concentration contrast medium. From there, rational CT angiographic injection protocols for a wide range of selectable acquisition times for 4-, 8- and 16-channel MDCT are proposed.

  View details for DOI 10.1016/S0720-048X(02)00365-0

  View details for Web of Science ID 000181595800015

  View details for PubMedID 12598032

• Multiple detector-row CT angiography of the renal and mesenteric vessels 3rd Bracco Symposium on MDCT Fleischmann, D. ELSEVIER IRELAND LTD. 2003: S79–S87

  Abstract

  Computed tomography angiography (CTA) of the abdomen with multiple detector-row computed tomography (MD-CT) is an effective technique for minimally invasive imaging of the renal arteries and the visceral vasculature. This article reviews the clinical and technical aspects of MD-CT angiography in terms of image acquisition and reconstruction parameters, contrast medium application, and three-dimensional visualization with special attention to renal and mesenteric vascular imaging. Because of its high sensitivity to detect renal artery stenosis on the one hand, and because a normal renal CTA virtually excludes the presence of a significant renal artery stenosis on the other hand, renal CTA plays a useful role in the management of patients with suspected renovascular hypertension. Mesenteric CTA is a useful tool for visualizing normal vascular anatomy and its variants-particularly in the setting of organ transplantation. Vascular pathology, e.g. atherosclerotic disease (abdominal angina), or aneurysms of the visceral arteries are reliably assessed with CTA. Mesenteric CTA is an invaluable adjunct to abdominal CT in the setting of abdominal emergencies, because of its ability to detect the causes of acute intestinal ischemia (superior mesenteric artery embolism or thrombosis, superior mesenteric vein thrombosis). Accurate timing of the CTA acquisition and the subsequent parenchymal phase acquisition relative to the contrast medium transit time is critical to obtain excellent image quality in double-pass abdominal CT acquisitions.

  View details for DOI 10.1016/S0720-048X(02)00364(02)00364-9

  View details for Web of Science ID 000181595800014

  View details for PubMedID 12598031

• Advanced Curved Planar Reformation: Flattening of Vascular Structures IEEE Visualization 2003 Kanitsar A, Wegenkittl R, Fleischmann D, Gröller E 2003: 43-50
• Bone segmentation in CT-angiography data using a probabilistic atlas 8th Workshop on Vision, Modeling, and Visualization (VMV 2003) Straka, M., Lacruz, A., Kochl, A., Dimitrov, L. I., Sramek, M., Fleischmann, D., Groller, E. AKADEMISCHE VERLAGSGESELLSCH AKA GMBH. 2003: 505–512

  View details for Web of Science ID 000221472600059

• Advanced curved planar reformation: Flattening of vascular structures IEEE Visualization 2003 Conference Kanitsar, A., Wegenkittl, R., Fleischmann, D., Groller, M. E. IEEE. 2003: 43–50

  View details for Web of Science ID 000189041100003

• Bone Segmentation in CT Angiography Data Using a Probabilistic Atlas Vision, Modeling, and Visualization VMV 2003 Straka M, La Cruz A, Köchl A, Dimitrov LI, Srámek M, Fleischmann D, Gröller E 2003: 505-512
• Endovascular stent-graft repair of complicated penetrating atherosclerotic ulcers of the descending thoracic aorta JOURNAL OF VASCULAR SURGERY Schoder, M., Grabenwoger, M., Holzenbein, T., Domanovits, H., Fleischmann, D., Wolf, F., Cejna, M., Lammer, J. 2002; 36 (4): 720-726

  Abstract

  To report our initial experience with endovascular stent-graft repair of complicated penetrating atherosclerotic ulcers as an alternative to surgery in patients with increased risk of perioperative morbidity and mortality.During a 2-year period, eight patients with complicated penetrating atherosclerotic ulcers of the descending thoracic aorta were treated with the Gore Excluder stent-graft. Patients (mean age, 70.6 years) presented with two to five comorbid conditions causing an increased risk for surgical repair. In addition to painful events, three patients presented with severe hemoptysis, one patient with shortness of breath, and one patient with dysphagia. All patients underwent emergency computed tomography, and diagnosis of contained rupture was confirmed in five patients. Computed tomographic findings included one to three penetrating ulcers per patient (n = 4), pseudoaneurysms (n = 5), additional intramural hematomas (n = 4), mediastinal bleeding (n = 2), and hematothoraces (n = 4). Through an iliac or femoral access site, a total of 11 stent-grafts were implanted under general (n = 5), epidural (n = 2), or spinal (n = 1) anesthesia.Deployment of stent-grafts was successful in all patients, and all sites of hemorrhage were sealed. The intramural hematoma resolved completely in three cases, and two pseudoaneurysms decreased in size. Intentional occlusion of the origin of left subclavian artery with the stent-graft in one patient was tolerated without left arm or cerebral symptoms. One patient experienced permanent paraplegia immediately after endovascular repair. There were no deaths during the hospital stay (range, 7-35 days; mean, 14.5 days). One patient was lost to follow-up after hospital discharge. The clinical observation period for the remaining seven patients was 38 to 99 weeks (mean, 60 weeks).Endovascular stent-graft repair in complicated penetrating atherosclerotic ulcers is an alternative therapeutic option to conventional thoracotomy, especially in patients at high risk of increased morbidity and mortality perioperatively and postoperatively.

  View details for DOI 10.1067/mva.2002.126090

  View details for Web of Science ID 000178617900012

  View details for PubMedID 12368732

• Present and future trends in multiple detector-row CT applications: CT angiography EUROPEAN RADIOLOGY Fleischmann, D. 2002; 12: S11-S15

  View details for Web of Science ID 000177530300003

  View details for PubMedID 12232656

• Images in cardiovascular medicine. Left main coronary artery compression by the pulmonary trunk in pulmonary hypertension. Circulation Bonderman, D., Fleischmann, D., Prokop, M., Klepetko, W., Lang, I. M. 2002; 105 (2): 265-?

  View details for PubMedID 11790711

• [CT angiography (CTA)]. Wiener medizinische Wochenschrift. Supplement Fleischmann, D. 2002: 53-58

  Abstract

  Computed tomography angiography (CTA) is today a well-established diagnostic technique for non-invasive vascular imaging and has replaced diagnostic intra-arterial angiography. Especially since the implementation of multi detector-row computed tomography (MDCT) the acquisition of isotropic data sets is possible, thus widening the spectrum of clinical application of multi detector-row computed tomography. Compared to intra-arterial angiography computed tomography angiography is less invasive and cheaper.

  View details for PubMedID 12621843

• CPR - Curved Planar Reformation IEEE Visualization 2002 Conference Kanitsar, A., Fleischmann, D., Wegenkittl, R., Felkel, P., Groller, M. E. IEEE. 2002: 37–44

  View details for Web of Science ID 000179397800003

• Christmas tree case study: Computed tomography as a tool for mastering complex real world objects with applications in computer graphics IEEE Visualization 2002 Conference Kanitsar, A., Theussl, T., Mroz, L., Sramek, M., Bartroli, A. V., Csebfalvi, B., Hladuvka, J., Fleischmann, D., Knapp, M., Wegenkittl, R., Felkel, P., Rottger, S., Guthe, S., Purgathofer, W., Groller, M. E. IEEE. 2002: 489–492

  View details for Web of Science ID 000179397800060

• Internal iliac artery embolization before endovascular repair of abdominal aortic aneurysms: Frequency, efficacy, and clinical results AMERICAN JOURNAL OF ROENTGENOLOGY Schoder, M., Zaunbauer, L., Holzenbein, T., Fleischmann, D., Cejna, M., Kretschmer, G., Thurnher, S., Lammer, J. 2001; 177 (3): 599-605

  Abstract

  The aim of our study was to assess the frequency, efficacy, and incidence of adverse effects of internal iliac artery embolization.Of 343 patients examined for stent-graft repair, 147 were suitable for endovascular treatment. Fifty-five patients underwent preprocedural embolization of the internal iliac artery either unilaterally (46 patients) or bilaterally (nine patients). Successful embolization was assessed angiographically and with helical CT follow-up examinations. Colonic ischemia was ruled out clinically or colonoscopically. Buttock claudication, and sexual dysfunction in men, were evaluated through a questionnaire.Embolization of the internal iliac artery increased by 16% the percentage of patients for whom endovascular repair was suitable. After successful embolization in all patients, routine CT follow-up examinations after a mean time of 16.7 months showed no evidence of endoleaks related to retrograde perfusion via embolized internal iliac arteries. Nevertheless, in all patients who had undergone embolization, a primary endoleak was detected in 43.4% at the first postoperative CT examination. None of our patients had evidence of colonic ischemia. Clinical follow-up data of 46 patients were available. Of these patients, mild to severe new onset buttock claudication was found in 13 (36.1%) of 36 patients with unilateral, and in eight (80%) of 10 patients with bilateral, internal iliac artery embolization (p = 0.03). Five (25%) of 20 men had an erectile dysfunction after the procedure.Embolization of the internal iliac artery is a safe and efficient procedure that increases the applicability for endovascular repair of aortoiliac aneurysms. However, buttock claudication and erectile dysfunction are a drawback in a substantial number of patients.

  View details for Web of Science ID 000170672000015

  View details for PubMedID 11517053

• Three-dimensional visualization of pulmonary thromboemboli in chronic thromboembolic pulmonary hypertension with multiple detector-row spiral computed tomography CIRCULATION Fleischmann, D., Scholten, C., Klepetko, W., Lang, I. M. 2001; 103 (24): 2993-2993

  View details for Web of Science ID 000169436000024

  View details for PubMedID 11413092

• Iliac arterial injuries after endovascular repair of abdominal aortic aneurysms: Correlation with iliac curvature and diameter RADIOLOGY Tillich, M., Bell, R. E., Paik, D. S., Fleischmann, D., Sofilos, M. C., Logan, L. J., Rubin, G. D. 2001; 219 (1): 129-136

  Abstract

  To determine the relationship between iliac arterial tortuosity and cross-sectional area and the occurrence of iliac arterial injuries following transfemoral delivery of endovascular prostheses for repair of abdominal aortic aneurysms.Iliac arterial curvature values and orthogonal cross-sectional areas were determined from helical computed tomographic (CT) data acquired in 42 patients prior to transfemoral delivery of aortic stent-grafts. The curvature and luminal cross-sectional area orthogonal to the median centerline were quantified every millimeter along the median centerline of the iliac arteries. An indicator of global iliac tortuosity, the iliac tortuosity index, was defined as the sum of the curvature values for all points with a curvature of 0.3 cm(-1) or greater, and cross-sectional area (CSA) was indexed for all points as the mean cross-sectional diameter (D = 2 radical[CSA/pi]). Following stent-graft deployment, helical CT data were analyzed for the presence of iliac arterial dissections independently by two reviewers.Eighteen dissections were detected in 16 patients. The iliac tortuosity index was significantly larger in iliac arteries with dissections (35.5 +/- 20.8 [mean +/- SD]) when compared with both nondissected contralateral iliac arteries in the same patients (26.1 +/- 21.0, P =.001) and iliac arteries in patients without any iliac arterial injury (20 +/- 9, P =.009). The tortuosity index was higher ipsilateral to the primary component delivery in 10 of 11 iliac dissections that developed along the primary component delivery route.A high degree of iliac arterial tortuosity appears to impart greater risk for the development of iliac arterial injuries in patients undergoing transfemoral delivery of endovascular devices.

  View details for Web of Science ID 000167667400019

  View details for PubMedID 11274547

• Long-term MRI observations of childhood-onset relapsing-remitting multiple sclerosis NEUROPEDIATRICS Balassy, C., Bernert, G., Wober-Bingol, C., Csapo, B., Kornek, B., Szeles, J., Fleischmann, D., Prayer, D. 2001; 32 (1): 28-37

  Abstract

  Long-term MRI follow-up of childhood-onset relapsing-remitting multiple sclerosis (RRMS) was carried out in 4 cases. MRI findings were correlated with clinical course and characteristic differences from adult-onset RRMS were elaborated.Two girls and one boy with true childhood-onset, and one girl with juvenile-onset RRMS underwent 5-16 MRI examinations within 6-8 years. The total number of lesions, the numbers of new, active, disappearing and reappearing lesions, infratentorial and U-fibre lesions, "giant" plaques and "black holes" were counted. Callosal atrophy and general brain atrophy were assessed. The findings were related to the physical status according to the Expanded Disability Status Scale (EDSS).Results showed that the primary differences in childhood-onset RRMS compared to adult-onset RRMS lie in the lack of, or slower development of irreversible changes ("black hole" formation, brain atrophy). Despite callosal atrophy and intensive U-fibre region involvement, school performance was unchanged. Regarding the frequency of "giant" lesions, an even more pronounced white matter involvement was found in our children compared to adults. All children exhibited a rather "benign" disease course. A more intensive remyelination, less severe neuronal loss, and higher functional brain plasticity at younger ages may account for these differences.

  View details for Web of Science ID 000167884600005

  View details for PubMedID 11315199

• Computed Tomography Angiography: A Case Study of Peripheral Vessel Investigation IEEE Visualization 2001 Kanitsar A, Wegenkittl R, Felkel P, Fleischmann D, Sandner D, Gröller E 2001: 477-480
• Computed tomography angiography: A case study of peripheral vessel investigation IEEE Visualization Conference Kanitsar, A., Wegenkittl, R., Felkel, P., Fleischmann, D., Sandner, D., Groller, E. IEEE. 2001: 477–480

  View details for Web of Science ID 000174051300066

• Equipment availability and diagnostic strategies for suspected pulmonary embolism in Austria EUROPEAN RADIOLOGY Schibany, N., Fleischmann, D., Thallinger, C., Schibany, A., Hahne, J., Ba-Ssalamah, A., Herold, C. J. 2001; 11 (11): 2287-2294

  Abstract

  The aim of this study was to investigate equipment availability and current diagnostic strategies for suspected pulmonary embolism (PE) in Austrian hospitals. A questionnaire was sent to the medical directors of all Austrian hospitals with emergency and/or surgical, orthopedic, and medical departments. The questionnaire contained questions regarding the available equipment suitable for the imaging diagnosis of PE, the first-line and second-line imaging tests for patients with suspected PE, and additional lower extremity venous imaging and laboratory tests that complement the diagnostic armamentarium. The return rate for questionnaires was 81% (127 of 157 hospitals). There were 97% of hospitals that had the equipment to perform sonography, 59% could perform pulmonary angiography, 54% spiral CT, 19% ventilation/perfusion (V/P) scintigraphy, and 4% perfusion scintigraphy alone. Spiral-CT angiography (SCTA) was the first-line imaging study for suspected PE in 56% of hospitals, followed by echocardiography and V/P scintigraphy. Lower extremity venous imaging (47%) and, interestingly, V/P scintigraphy (43%), served as second-line imaging tests. D-dimer tests were included in the diagnostic strategy in 74% of hospitals. Spiral-CT angiography is the most commonly used primary method for suspected PE in Austrian hospitals. The V/P scintigraphy is available only in a minority of hospitals to investigate patients with suspected PE. When V/P scintigraphy is available, however, it is employed in a large number of patients per annum.

  View details for Web of Science ID 000172277300024

  View details for PubMedID 11702174

• High-resolution CT of diffuse interstitial lung disease: key findings in common disorders EUROPEAN RADIOLOGY Schaefer-Prokop, C., Prokop, M., Fleischmann, D., Herold, C. 2001; 11 (3): 373-392

  Abstract

  High-resolution CT (HRCT) is the radiological imaging technique that most closely reflects changes in lung structure. It represents the radiological method of choice for the diagnostic work-up of patients with known or suspected diffuse interstitial lung disease. A single HRCT finding is frequently nonspecific, but the combination of the various HRCT findings together with their anatomic distribution can suggest the most probable diagnosis. The purpose of this article is to summarize the classic HRCT features of the most common diffuse interstitial lung diseases. Lists of differential diagnoses and distinguishing key features are provided to improve diagnostic confidence. The presence of classic HRCT features often obviates the need for biopsy. In patients with atypical findings, HRCT can be used to determine the most appropriate biopsy site.

  View details for Web of Science ID 000167273600002

  View details for PubMedID 11288840

• Early pulmonary involvement in ankylosing spondylitis: Assessment with thin-section CT CLINICAL RADIOLOGY Turetschek, K., Ebner, W., Fleischmann, D., Wunderbaldinger, P., Erlacher, L., Zontsich, T., Bankier, A. A. 2000; 55 (8): 632-636

  Abstract

  To determine the frequency and the distribution of early pulmonary lesions in patients with ankylosing spondylitis (AS) and a normal chest X-ray on thin-section CT and to correlate the CT findings with the results of pulmonary function tests and clinical data.Twenty-five patients with clinically proven AS and no history of smoking underwent clinical examinations, pulmonary function tests (PFT), chest radiography, and thin-section CT. Four of 25 patients (16%), who had obvious signs on plain films suggestive of pre-existing disorders unrelated to AS were excluded.Fifteen of 21 patients (71%) had abnormalities on thin-section CT. The most frequent abnormalities were thickening of the interlobular septa in seven of 21 patients (33%), mild bronchial wall thickening in (6/21, 29%), pleural thickening and pleuropulmonary irregularities (both 29%) and linear septal thickening (6/21, 29%). In six patients there were no signs of pleuropulmonary involvement. Eight of 15 patients (53%) with abnormal and four of six patients (67%) with normal CT findings revealed mild restrictive lung function impairment.Patients with AS but a normal chest radiograph frequently have abnormalities on thin-section CT. As these abnormalities are usually subtle and their extent does not correlate with functional and clinical data, the overall routine impact of thin-section CT in the diagnosis of AS is limited.

  View details for Web of Science ID 000088802000009

  View details for PubMedID 10964736

• Partial fat-saturated contrast-enhanced three-dimensional MR angiography compared with non-fat-saturated and conventional fat-saturated MR angiography RADIOLOGY Hilfiker, P. R., Herfkens, R. J., Heiss, S. G., Alley, M. T., Fleischmann, D., Pelc, N. J. 2000; 216 (1): 298-303

  Abstract

  Abdominal three-dimensional magnetic resonance angiography was performed in 35 patients in the equilibrium phase without fat saturation, with conventional fat saturation, and with fast partial fat saturation. Qualitative and quantitative evaluation demonstrated significantly better vessel visualization with both fat-saturated techniques. The partial fat-saturated technique provided water-specific images within a breath hold, reducing motion artifacts significantly.

  View details for Web of Science ID 000087829500044

  View details for PubMedID 10887265

• Stair-step artifacts with single versus multiple detector-row helical CT 85th Annual Meeting and Scientific Assembly of the Radiological-Society-of-North-America (RSNA) Fleischmann, D., Rubin, G. D., Paik, D. S., Yen, S. Y., Hilfiker, P. R., Beaulieu, C. F., Napel, S. RADIOLOGICAL SOC NORTH AMERICA. 2000: 185–96

  Abstract

  To compare the effects of acquisition parameters on the magnitude and appearance of artifacts between single and multiple detector-row helical computed tomography (CT).A cylindric (12.7 x 305.0-mm) acrylic rod inclined 45 degrees relative to the z axis was scanned at the isocenter and 100 mm from the isocenter with single detector-row (single-channel) helical CT (beam width, 1-10 mm; pitch, 1.0, 2.0, or 3.0) and multiple detector-row (four-channel) helical CT (detector width, 1. 25, 2.5, 3.75, and 5 mm; pitch, 0.75 or 1.5). The SD of radius measurements along the rod (SD(r)) was used to quantify artifacts in all 72 data sets and to analyze their frequency patterns. Volume-rendered images of the data sets were ranked by six independent and blinded readers; findings were correlated with acquisition parameters and SD(r) measurements.SD(r) was smaller in four- than in single-channel helical CT for any given table increment (TI). In single-channel helical CT, SD(r) increased linearly with beam width and geometrically with pitch. In four-channel helical CT, SD(r) measurements were directly proportional to the TI, regardless of the detector width and pitch combination used. Off-center object position on average increased SD(r) by a factor of 1.6 for single-channel helical CT and by a factor of 2.0 for four-channel helical CT. Subjective rankings of image quality correlated excellently with SD(r) (Spearman r = 0.94, P <.001).Artifacts are quantitatively and subjectively smaller with four- compared with single-channel helical CT for any given TI.

  View details for Web of Science ID 000087829500026

  View details for PubMedID 10887247

• Computed tomographic angiography: Historical perspective and new state-of-the-art using multi detector-row helical computed tomography Workshop on Multiple Perspectives in Magnetic Resonance Imaging Contrast Rubin, G. D., Shiau, M. C., Schmidt, A. J., Fleischmann, D., Logan, L., Leung, A. N., Jeffrey, R. B., Napel, S. LIPPINCOTT WILLIAMS & WILKINS. 1999: S83–S90

  Abstract

  Since its clinical introduction in 1991, volumetric computed tomography scanning using spiral or helical scanners has resulted in a revolution for diagnostic imaging. In addition to new applications for computed tomography, such as computed tomographic angiography and the assessment of patients with renal colic, many routine applications such as the detection of lung and liver lesions have substantially improved. Helical computed tomographic technology has improved over the past eight years with faster gantry rotation, more powerful X-ray tubes, and improved interpolation algorithms, but the greatest advance has been the recent introduction of multi detector-row computed tomography scanners. These scanners provide similar scan quality at a speed gain of 3-6 times greater than single detector-row computed tomography scanners. This has a profound impact on the performance of computed tomography angiography, resulting in greater anatomic coverage, lower iodinated contrast doses, and higher spatial resolution scans than single detector-row systems.

  View details for Web of Science ID 000084391500012

  View details for PubMedID 10608402

• Thoracic venous anatomy delineated by malpositioned central venous catheters on plain chest films JOURNAL OF THORACIC IMAGING Wunderbaldinger, P., Bankier, A. A., Kreuzer, S., Turetschek, K., Fleischmann, D., Herold, C. J. 1999; 14 (4): 286-292

  Abstract

  The aim of this essay was to demonstrate the thoracic venous anatomy as delineated by malpositioned central venous catheters on plain chest radiographs. We therefore used the didactic advantage of clinically inadvertent catheter positions. This approach was chosen to illustrate venous anatomy with plain chest radiographs, and, thereby, to recognize malpositions promptly on the modality with which positions of central venous catheters is routinely performed.

  View details for Web of Science ID 000082932000009

  View details for PubMedID 10524810

• Evolution of CT findings in patients with cystic fibrosis AMERICAN JOURNAL OF ROENTGENOLOGY Helbich, T. H., Heinz-Peer, G., Fleischmann, D., Wojnarowski, C., Wunderbaldinger, P., Huber, S., Eichler, I., Herold, C. J. 1999; 173 (1): 81-88

  Abstract

  The aim of our study was to assess the evolution of pulmonary CT findings in cystic fibrosis patients.Serial CT examinations were performed in four different follow-up periods on 107 patients with cystic fibrosis. Lung images of the initial and follow-up CT were reviewed and scored for specific morphologic findings. CT findings were correlated with the results of the pulmonary function tests and clinical (Shwachman-Kulczycki) scores.Morphologic changes were minor within the first 18 months of follow-up compared with the period after 18 months. The increase of the overall score was significantly higher in groups with follow-up periods longer than 18 months compared with groups with follow-up periods shorter than 18 months. Various components of morphologic changes contributed to the sequential changes seen on the CT scans. All morphologic changes and the CT scores correlated significantly (p < .0001) with pulmonary function tests and clinical score. CONCLUSION. Serial CT scans allow assessment of the evolution of pulmonary abnormalities in patients with cystic fibrosis. CT seems to have advantages over pulmonary function tests and clinical scoring in the depiction of pulmonary changes over time.

  View details for Web of Science ID 000081010900017

  View details for PubMedID 10397104

• Subjective differentiation of normal and pathological bronchi on thin-section CT: impact of observer training EUROPEAN RESPIRATORY JOURNAL Bankier, A. A., Fleischmann, D., de Maertelaer, V., Kontrus, M., Zontsich, T., Hittmair, K., Mallek, R. 1999; 13 (4): 781-786

  Abstract

  The effect of observer training on sensitivity, specificity and interobserver agreement in the differentiation between normal and pathological bronchi on computed tomography (CT) was studied. The wall thickness of bronchi with normal walls and with pathologically thickened walls were subjectively scored by three independent observers before and after a training period of 2 weeks. Sensitivity, specificity and interobserver agreement were calculated for reading sessions before and after training. Increase and decrease in agreement after training were determined. There was a statistically significant difference (p=0.001) between objectively measured wall thickness of normal and pathological bronchi, both for reference bronchi and for bronchi used for reading sessions. While training increased interobserver agreement, it had no effect on sensitivity (0.46 versus 0.44 after training) and specificity (0.71 versus 0.72 after training) in detecting pathological bronchi. Increased agreement after training was significantly (p=0.001) more frequent than decreased agreement. There is a discrepancy between the effect of training on interobserver agreement and on sensitivity and specificity in the subjective differentiation between normal and pathological bronchi. Interobserver agreement alone is not a reliable indicator of a beneficial effect of training in the evaluation of this parameter.

  View details for Web of Science ID 000080401100014

  View details for PubMedID 10362040

• Quiz case 5 EUROPEAN JOURNAL OF RADIOLOGY Henk, C., Fleischmann, D., Turetschek, K., Mostbeck, G. 1999; 29 (3): 259-261

  View details for Web of Science ID 000080831900007

  View details for PubMedID 10399612

• [Diagnostic imaging in intensive care. Techniques, indications, diagnostic signs--II]. Der Internist Bankier, A., Fleischmann, D., Aram, L., Heimberger, K., Schindler, E., Herold, C. J. 1999; 40 (3): W294-304

  View details for PubMedID 10205755

• Imaging in intensive care medicine - Techniques, indications, diagnostic signs - Part one INTERNIST Bankier, A., Fleischmann, D., Aram, L., Heimberger, K., Schindler, E., Herold, C. J. 1999; 40 (2): 190-204

  View details for Web of Science ID 000078880900010

• Contrast optimization in CT angiography RADIOLOGE Hittmair, K., Wunderbaldinger, P., Fleischmann, D. 1999; 39 (2): 93-99

  Abstract

  This paper compares different contrast injection techniques for optimizing vessel contrast in CT angiography (CTA). The optimal vessel contrast shall be defined as constant strong enhancement confined to the scanning interval. This "plateau enhancement" guarantees high-quality CTA images and should therefore be approximated during every CTA examination by an appropriate contrast injection protocol. With well-established injection techniques such as the standard bolus technique (constant uniphasic contrast bolus for all patients) or adjustment of the scan delay, considerable individual differences in the arterial enhancement can be observed, and a nondiagnostic examination or an inefficient use of contrast agent might be the result in a particular patient. Therefore, two sophisticated mathematical models have recently been developed for analyzing the individual enhancement characteristics. These models can be exploited to predict the arterial enhancement for any given intravenous contrast bolus in any patient and to optimize the contrast bolus in order to approach the ideal "plateau enhancement." These techniques have to prove their effectiveness in larger clinical series.

  View details for Web of Science ID 000079005900001

  View details for PubMedID 10093834

• [Diagnostic imaging in intensive care medicine. Techniques, indications, diagnostic signs--I]. Der Internist Bankier, A., Fleischmann, D., Aram, L., Heimberger, K., Schindler, E., Herold, C. J. 1999; 40 (2): W190-204

  View details for PubMedID 10097978

• Imaging in intensive care medicine. Techniques, indications, diagnostic signs: part II RADIOLOGE Bankier, A., Fleischmann, D., Aram, L., Heimberger, K., Schindler, E., Herold, C. J. 1998; 38 (12): 1089-1099

  View details for Web of Science ID 000077910300018

  View details for PubMedID 9931987

• [Imaging in intensive care. Methods, indications, diagnostic signs. I]. Der Radiologe Bankier, A., Fleischmann, D., Aram, L., Heimberger, K., Schindler, E., Herold, C. J. 1998; 38 (11): 972-986

  View details for PubMedID 9861660

• Imaging in intensive care medicine. Techniques, indications, diagnostic signs: Part I RADIOLOGE Bankier, A., Fleischmann, D., Aram, L., Heimberger, K., Schindler, E., Herold, C. J. 1998; 38 (11): 972-986

  View details for Web of Science ID 000077305100014

• Radiographic findings in patients with acquired immunodeficiency syndrome, pulmonary infection, and microbiologic evidence of Mycobacterium xenopi JOURNAL OF THORACIC IMAGING Bankier, A. A., Stauffer, F., Fleischmann, D., Kreuzer, S., Strasser, G., Mossbacher, U., Mallek, R. 1998; 13 (4): 282-288

  Abstract

  The authors studied radiographs and clinical histories of 29 patients with acquired immunodeficiency syndrome, symptoms of pulmonary infection, and simultaneous microbiologic evidence of Mycobacterium xenopi in the respiratory tract. The presence, nature, and distribution of radiographic abnormalities were determined and analyzed in accord with clinical information. In 26 (90%) patients, M. xenopi was the only microorganism that could be isolated. Chest radiographs were normal in 13 patients (45%) and abnormal in 16 patients (55%). Radiographic abnormalities were bilateral in 94% of cases and predominantly involved the lower lobes. Patchy peribronchial opacities (44%) and miliary nodules (24%) were the most common abnormalities. Reticular opacities and parenchymal consolidation were seen in 12% of patients. Pleural effusion was seen in 18% of patients. No patients had cavitations or adenopathy. There was no statistically significant difference regarding the mean age (38.7+/-7.3 years vs. 40.2+/-11.0 years), the duration of clinically evident human immunodeficiency virus infection (2.7+/-1.2 years vs. 2.8+/-1.4 years), and the mean of CD4 cell counts (50.6+/-15.3 cells/ml vs. 47.4+/-15.9 cells/ml) between the patients with and without abnormalities on chest radiographs. In patients with acquired immunodeficiency syndrome, pulmonary infection, and simultaneous microbiologic evidence of M. xenopi, chest radiographs can be normal in a substantial number of cases. When radiographic abnormalities are present, they differ from those seen in patient not infected with the human immunodeficiency virus who had pulmonary infection caused by M. xenopi and from patients with acquired immunodeficiency syndrome and pulmonary infection with nontuberculous mycobacteria other than M. xenopi. Although these findings are not specific, they may be of importance in the imaging of patients with acquired immunodeficiency syndrome, notably in areas where M. xenopi is endemic.

  View details for Web of Science ID 000076448600007

  View details for PubMedID 9799136

• [Spiral CT angiography in diagnosis of acute pulmonary embolism. What factors modify implementation of standard algorithms?]. Der Radiologe Bankier, A., Herold, C. J., Fleischmann, D., Janata-Schwatczek, K. 1998; 38 (4): 248-255

  Abstract

  Debate about the potential implementation of Spiral-CT in diagnostic algorithms of pulmonary embolism are often focussed on sensitivity and specificity in the context of comparative methodologic studies. We intend to investigate whether additional factors might influence this debate.On the basis of the current literature and of own experience we study the influence of factors such as availability, acceptance, patient-outcome, and cost effectiveness-studies on the potential implementation of Spiral-CT in diagnostic algorithms of pulmonary embolism. This information is analyzed together with data from comparative methodologic studies.The factors availability, acceptance, patient-outcome, and cost-effectiveness-studies do have substantial influence on the implementation of Spiral-CT in the diagnostic algorithms of pulmonary embolism. Incorporation of these factors into the discussion might lead to more flexible and more patient-oriented algorithms for the diagnosis of pulmonary embolism.Availability of equipment, acceptance among clinicians, patient-outcome, and cost-effectiveness evaluations should be implemented into the debate about potential implementation of Spiral-CT in routine diagnostic imaging algorithms of pulmonary embolism.

  View details for PubMedID 9622818

• Spiral-CT-angiography of acute pulmonary embolism: factors that influence the implementation into standard diagnostic algorithms RADIOLOGE Bankier, A., Herold, C. J., Fleischmann, D., Janata-Schwatczek, K. 1998; 38 (4): 248-255

  View details for Web of Science ID 000073615300004

• Comparison of T2-weighted and fluid-attenuated inversion-recovery fast spin-echo MR sequences in intracerebral AIDS-associated disease AMERICAN JOURNAL OF NEURORADIOLOGY Thurnher, M. M., Thumher, S. A., Fleischmann, D., Steuer, A., Rieger, A., Helbich, T., Trattnig, S., Schindler, E., Hittmair, K. 1997; 18 (9): 1601-1609

  Abstract

  To compare the value of fast fluid-attenuated inversion-recovery (FLAIR) with T2-weighted fast spin-echo MR imaging in the detection of acquired immunodeficiency virus (AIDS)-related lesions of the brain.Forty-four human immunodeficiency virus (HIV)-positive patients were examined with both sequences on either a 1.0-T or a 1.5-T MR system. The number, size, location, and conspicuity of the lesions were evaluated by two independent observers. Contrast ratios between lesions and normal brain/cerebrospinal fluid were determined, and contrast-to-noise ratios were calculated.FLAIR was found to be superior to T2-weighted fast spin-echo in detection of small lesions and of lesions located in cortical/subcortical regions and deep white matter. The two techniques were equal in delineation of lesions larger than 2 cm and for lesions located in the basal ganglia and posterior fossa. In 24 patients, more lesions were detected with the FLAIR fast spin-echo technique. Lesion/cerebrospinal fluid contrast ratios and contrast-to-noise ratios were significantly higher for the FLAIR fast spin-echo sequences than for the T2-weighted fast spin-echo sequences.FLAIR allows early detection of small lesions in subcortical and cortical locations, especially in HIV encephalitis. Because of its improved lesion detection rate and greater overall lesion conspicuity, we believe FLAIR is useful in the evaluation of subtle changes in the brains of AIDS patients with central nervous system disease, and could even replace the T2-weighted fast spin-echo technique.

  View details for Web of Science ID A1997YC79700001

  View details for PubMedID 9367306

• Progressive multifocal leukoencephalopathy in AIDS: initial and follow-up CT and MRI NEURORADIOLOGY Thurnher, M. M., Thurnher, S. A., Muhlbauer, B., Hainfellner, J. A., Steuer, A., Fleischmann, D., Trattnig, S., Budka, H., Schindler, E. 1997; 39 (9): 611-618

  Abstract

  We sought to determine the value of follow-up CT and MRI in patients with acquired immuno-deficiency syndrome (AIDS) and progressive multifocal leukoencephalopathy (PML). We reviewed 50 CT and 19 MRI examinations performed in 21 biopsy- or autopsy-proven cases of PML; 17 patients had follow-up examinations (mean time 5.9 weeks). The radiological examinations were correlated with pathological findings at autopsy. On initial imaging studies, 73 lesions were found. On follow-up, the most striking feature was rapid progression in both size and number of the lesions (from a mean of 3.2 to 6.9 per patient). One third of the patients showed increasing mass effect. A central area suggesting necrosis, of variable size, was found in 12/16 patients. Autopsy revealed macroscopic necrotic changes in the lesions in 11/16 patients.

  View details for Web of Science ID A1997XX51400001

  View details for PubMedID 9335057

• Pulmonary hypertension and cor pulmonale RADIOLOGE Henk, C. B., Gabriel, H., Fleischmann, D., Schoder, M., Mostbeck, G. H. 1997; 37 (5): 388-401

  Abstract

  Pulmonary hypertension is a severe disorder of the pulmonary circulation and occurs in a variety of vascular and parenchymal lung diseases. It leads to volume and/or pressure overload of the right ventricle and finally to right heart failure. Pulmonary vascular diseases such as chronic pulmonary embolism cause a drastic increase in pulmonary vascular resistance, which results in extremely high pulmonary artery pressures that can even reach systemic levels. On the other hand, moderate pulmonary hypertension can also occur in chronic obstructive and restrictive lung diseases. For a long time, the diagnosis of pulmonary hypertension and cor pulmonale was based upon findings in echocardiography and right heart catheterization. Today modern imaging techniques allow the radiologist to assess right ventricular and pulmonary artery morphology and function. The application of spiral CT, electron-beam CT and MRT permits the diagnosis and differential diagnosis of pulmonary hypertension and also the evaluation and follow-up of underlying vascular or parenchymal lung disorders. In addition, quantification of right ventricular function and calculation of pulmonary hemodynamic parameters are possible.

  View details for Web of Science ID A1997XN77700007

  View details for PubMedID 9312782

• Radiographic detection of intrabronchial malpositions of nasogastric tubes and subsequent complications in intensive care unit patients INTENSIVE CARE MEDICINE Bankier, A. A., WIESMAYR, M. N., Henk, C., Turetschek, K., Winkelbauer, F., Mallek, R., Fleischmann, D., Janata, K., Herold, C. J. 1997; 23 (4): 406-410

  Abstract

  The aim of our study was to illustrate the radiographic spectrum of the intrabronchial malposition of nasogastric tubes and subsequent complications, and to discuss the role of radiography in the detection of such malpositions.Retrospective clinical investigation.Tertiary care university teaching hospital.We reviewed chest radiographs of 14 intensive care patients with nasogastric tubes malpositioned in the tracheobronchial tree. The site and anatomic location of the malposition were recorded. Complications due to tube malpositioning were monitored on follow-up radiographs and on computed tomographic examinations, which were available in 4 patients.Nine of 14 nasogastric tubes were inserted in the right and 5 in the left tracheobronchial tree. Tube tips were malpositioned in the lower lobe bronchi (50%), the intermediate bronchus (36%), and the main bronchi (14%). There was perforation of the bronchial system with subsequent pneumothorax in 4 patients. In 4 other patients, pneumonia developed at the former site of the malpositioned tube tip. Radiographic detection of nasogastric tube malpositioning was prompt in 9 patients and delayed in 5 patients.Whereas clinical signs of nasogastric tube malpositioning in intensive care patients may be absent or misleading, chest radiography can accurately detect nasogastric tube malpositions in the tracheobronchial tree, may prevent complications, and avoid the use of further costly or invasive diagnostic techniques.

  View details for Web of Science ID A1997WX30400008

  View details for PubMedID 9142579

• Radiographically occult scaphoid fractures: Value of MR imaging in detection RADIOLOGY Breitenseher, M. J., Metz, V. M., Gilula, L. A., Gaebler, C., Kukla, C., Fleischmann, D., Imhof, H., Trattnig, S. 1997; 203 (1): 245-250

  Abstract

  To evaluate the diagnostic value of magnetic resonance (MR) imaging in patients with clinical suspicion of scaphoid fractures and normal initial plain radiographs.MR imaging was performed within 7 days after trauma in 42 patients with clinical suspicion of scaphoid fractures and normal plain radiographs. T1-weighted spin-echo, T2*-weighted gradient-echo, and short inversion time inversion-recovery (STIR) sequences were performed. MR images were evaluated independently by two radiologists. Six-week follow-up radiographs were used as a standard to diagnose fractures.MR imaging depicted occult fractures of the scaphoid bone in 14 patients (33%), the capitate bone in four (10%), the trapezium in one (2%), and the distal radius in two (5%). All wrist fractures were detected with a combination of STIR and T1-weighted spin-echo sequences. The sensitivity and specificity for detection of radiographically occult fractures of the wrist were 100% each for the first and 95% and 100%, respectively, for the second radiologist with an almost perfect interobserver agreement (K = 0.953).MR imaging has a high sensitivity for detection of fractures of the scaphoid bone and wrist not evident on plain radiographs and may enable early diagnosis and treatment.

  View details for Web of Science ID A1997WP24100042

  View details for PubMedID 9122402

• Severity assessment of acute pulmonary embolism with spiral CT: Evaluation of two modified angiographic scores and comparison with clinical data JOURNAL OF THORACIC IMAGING Bankier, A. A., Janata, K., Fleischmann, D., Kreuzer, S., Mallek, R., Frossard, M., Domanovits, H., Herold, C. J. 1997; 12 (2): 150-158

  Abstract

  Spiral computed tomography (CT) has shown promising results in the detection of acute pulmonary embolism. The aim of this study was to investigate whether the severity of acute pulmonary embolism could be quantitatively assessed with spiral CT examinations and to test the potential clinical impact of this information. In a consecutive series of 123 patients screened with spiral CT for suspected acute pulmonary embolism, 31 patients (25%) had evidence of emboli. The severity of pulmonary arterial obstruction in those 31 spiral CT examinations was evaluated by two independent observers using angiographic scores previously described by Walsh (29) and Miller (30), adapted to the needs of spiral CT. Clinical patient subgroups were defined according to oxygen saturation, heart rate, and echocardiographic signs of right ventricular strain. CT severity scores were then correlated to each other and to clinical parameters using the Spearman rank test. Interobserver agreement was calculated using the analysis of variance. Both modified Walsh and Miller scores were readily reproducible and showed interobserver agreements of 0.85 and 0.96, respectively (p = 0.001). Patients with mild and marked clinical abnormalities showed statistically significant differences between CT severity scores. Differences between severity scores of patients with moderate and marked clinical abnormalities were somewhat significant. No significant mean severity score differences were seen between patients with mild and moderate clinical abnormalities. Although correlations of severity scores and detailed clinical parameters within the defined subgroups were moderate to poor, threshold scores greater than 10 (Miller) and greater than 11 (Walsh) always indicated marked clinical abnormalities. The modified scores presented in this study constitute a readily reproducible method for the quantitative assessment of acute pulmonary embolism severity on spiral CT examinations.

  View details for Web of Science ID A1997XB63900012

  View details for PubMedID 9179827

• MRI of the sinus tarsi in acute ankle sprain injuries JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Breitenseher, M. J., Haller, J., Kukla, C., Gaebler, C., Kaider, A., Fleischmann, D., Helbich, T., Trattnig, S. 1997; 21 (2): 274-279

  Abstract

  Our goal was to evaluate the visibility and incidence of traumatic abnormalities of the sinus tarsi in patients with acute ankle sprain injuries and compare these findings with the extent of lateral ankle ligament injuries on MRI.Sixty athletically active patients (aged 18-45 years) with recent inversion trauma (< or = 7 days) underwent MRI. Replacement of fat tissue in the sinus tarsi was recorded. Inter/intraobserver agreement was calculated (kappa-statistics). Injuries of the three lateral ligaments, evaluated by MRI, were graded according to partial (1 point) or complete (2 points) tears for each of three lateral ligaments (together 0-6 points) and were compared with sinus tarsi abnormalities.In 26 patients (43%), replacement of sinus tarsi fat tissue was depicted by MRI. Inter/intraobserver agreement for MR changes of the sinus tarsi was good to moderate (kappa = 0.675/0.584). Grade of lateral ankle ligament injury showed a statistically significant difference (p = 0.033) between the two sinus tarsi groups (normal/abnormal).Acute ankle sprain injuries, evaluated by MRI, are associated with acute abnormalities of the sinus tarsi in 43% of patients and correlate with the extent of lateral ankle ligament tears.

  View details for Web of Science ID A1997WM65500020

  View details for PubMedID 9071300

• Diagnostic imaging in lung transplantation RADIOLOGE Bankier, A. A., Hormann, M., Aram, L., Fleischmann, D. 1997; 37 (3): 211-219

  View details for Web of Science ID A1997WR38700005

• [Diagnostic imaging within the scope of lung transplantation]. Der Radiologe Bankier, A. A., Hörmann, M., Aram, L., Fleischmann, D. 1997; 37 (3): 211-219

  Abstract

  Recent progress in both surgical techniques and therapeutic medication of immunosupression have made lung transplantation a promising option for patients with untreatable diseases of the lung parenchyma. Because preoperatively and postoperatively diagnostic imaging has crucial importance for patient management and clinical decision making we aim to describe imaging features of frequent pathologies in patients after lung transplantation.We reviewed radiological examinations of patients after lung transplantation performed at our institution over a period of four years, and exemplary cases were selected for presentation. Our interest was focussed on both conventional and CT-imaging of postoperative alterations, infections, organ rejection, and pathologies of the airways. Moreover, post-biopsy alterations and lymphoproliferative disorders were documented. Together with clinical information we aimed to give a concise description of specific pathologic entities. Also, the diagnostic impact of more recent techniques such as spiral-CT and thin-section CT should be discussed.In cases of early postoperative pathologies and in infections conventional radiography is diagnostically reliable when interpreted together with clinical information. In cases of acute or chronic organ rejection, of lymphoproliferative disorders, of diseases of central or small airways, and for the choice of an appropriate biopsy site, CT has proved to be a valuable imaging modality. Spiral-CT allows airway volumetry in cases of strictures or dehiscence, thin-section CT enables assessment of subtle parenchymal pathologies, notably in cases of chronic organ rejection.The radiographic findings described below represent specific pathogenetic entities in lung-transplant patients (postoperative alterations, infections, posttransplant lymphoproliferative disorders). Their accurate recognition will have a positive impact on the further clinical history. In the near future, more sophisticated CT techniques should widen our pathogenetic knowledge of alterations in transplanted lungs.

  View details for PubMedID 9182310

• Azygos arch cannulation by central venous catheters: Radiographic detection of malposition and subsequent complications JOURNAL OF THORACIC IMAGING Bankier, A. A., Mallek, R., WIESMAYR, M. N., Fleischmann, D., Kranz, A., Kontrus, M., Knapp, S., Winkelbauer, F. W. 1997; 12 (1): 64-69

  Abstract

  The aim of this study was to determine the frequency of radiographically evident central venous catheter misplacement in the azygos arch and to analyze whether the frequency of azygos arch cannulation is dependent on the anatomical site of catheter insertion. We reviewed 1,287 postprocedural examinations and 3,441 follow-up examinations. Catheters had been inserted through the left (6%) or right (15%) internal jugular veins and through the left (32%) or right (46%) subclavin veins. Radiographs were analyzed for possible catheter malposition in the azygos arch and for complications related to this malposition. Catheter malposition in the azygos arch was seen on 16/1,287 (1.2%) postprocedural radiographic examinations. Of the 16 malpositioned catheters, 11 (69%) had been inserted in the left subclavian vein, three (19%) in the left jugular vein, two (12%) in the right subclavian vein, and none (0%) in the right jugular vein. There was a statistically significant difference in the frequency of azygos arch cannulation between left- and right-sided catheters (p = 0.001). All complications consisted of venous perforations and were seen in three of 16 cases (19%). Azygos arch cannulation is a rare but hazardous central venous catheter malposition that occurs early after catheter insertion and carries a substantial risk for complication. The risk for azygos arch cannulation is substantially increased if catheters are inserted in left-sided veins. Because of the severity of subsequent complications, radiologists should be vigilant in the detection of this rare malposition.

  View details for Web of Science ID A1997WA70200010

  View details for PubMedID 8989762

• Imaging procedure in intensive care medicine .2. Techniques, indications, diagnostic signs ANAESTHESIST Bankier, A. A., Fleischmann, D., Aram, L., Heimberger, K., Schindler, E., Herold, C. J. 1996; 45 (9): 869-880

  View details for Web of Science ID A1996VK84900016

  View details for PubMedID 8967607

• Deep venous thrombosis of the lower extremity efficacy of spiral CT venography compared with conventional venography in diagnosis RADIOLOGY Baldt, M. M., Zontsich, T., Stumptlen, A., Fleischmann, D., Schneider, B., Minar, E., Mostbeck, G. H. 1996; 200 (2): 423-428

  Abstract

  To compare the efficacy of spiral computed tomographic (CT) venography with conventional venography in the diagnosis of suspected deep venous thrombosis (DVT).In a prospective study, 52 consecutive patients with clinically suspected unilateral or bilateral DVT were studied with CT venography and conventional venography. In cases in which conventional venographic findings were inconclusive, color-coded duplex sonography and follow-up examinations were performed to make a final diagnosis. CT venography of both extremities covered a 100-cm section from the ankle to the inferior vena cava (IVC). Contrast material diluted with saline was injected in a dorsal vein of each foot. CT and conventional venography (including color-coded duplex sonography and follow-up findings) were correlated for three venous regions for each patient.Correlation was excellent between CT and conventional venographic findings in the detection of DVT. The sensitivity of CT venography was 100% (confidence interval: 0.92, 1.00), specificity was 96% (confidence interval: 0.84, 0.98), positive predictive value was 91%, and negative predictive value was 100%. CT venography more clearly demonstrated thrombus extension of DVT into the pelvic veins and IVC than conventional venography alone.CT venography is a valuable tool in the diagnosis of DVT. Compared with conventional venography, CT requires use of 80% less contrast material.

  View details for Web of Science ID A1996UY07800023

  View details for PubMedID 8685336

• Pleural and pulmonary alterations caused by rheumatoid arthritis RADIOLOGE Bankier, A. A., Fleischmann, D., Kiener, H. P., WIESMAYR, M. N., Herold, C. J. 1996; 36 (8): 637-645

  View details for Web of Science ID A1996VE70100007

• Imaging in intensive-care - Techniques, indications, diagnostics ANAESTHESIST Bankier, A. A., Fleischmann, D., Aram, L., Heimberger, K., Schindler, E., Herold, C. J. 1996; 45 (8): 769-786

  View details for Web of Science ID A1996VD39300013

• [Pleural and pulmonary changes within the scope of rheumatoid arthritis]. Der Radiologe Bankier, A. A., Fleischmann, D., Kiener, H. P., WIESMAYR, M. N., Herold, C. J. 1996; 36 (8): 637-645

  Abstract

  Pulmonary complications caused by rheumatoid arthritis are a clinically relevant aspect of this chronic arthropathy. Those complications can involve all parts of the thorax, including the lung parenchyma, the pleura, and the thoracic cage. The most common complications are necrobiotic nodules, pleural abnormalities, Caplan's syndrome, parenchymal fibrosis, bronchiolitis obliterans, and iatrogenic damage of lung the parenchyma. This article reviews pulmonary abnormalities induced by rheumatoid arthritis and their clinical and radiological findings. In addition, the role of different imaging modalities in the diagnostic work-up of pulmonary complications caused by rheumatoid arthritis is discussed.

  View details for PubMedID 8975281

• [Imaging in intensive care medicine. I. Techniques, indications, diagnostic signs]. Der Anaesthesist Bankier, A. A., Fleischmann, D., Aram, L., Heimberger, K., Schindler, E., Herold, C. J. 1996; 45 (8): 769-786

  View details for PubMedID 8967593

• [Calcium in the lung or: it might not always be tuberculosis]. Der Radiologe Henk, C. B., Liskutin, J., Fleischmann, D., Mostbeck, G. H. 1996; 36 (7): 534-542

  Abstract

  Pulmonary calcifications are a frequent finding in CT examinations of the chest. In many cases, characteristic CT morphology and distribution of pulmonary and mediastinal calcifications may lead to a straightforward specific diagnosis of the underlying disease. In that respect, calcifications are often the residual finding of previous infections. Less often, they may be due to neoplasms, metabolic disorders, occupational exposure or previous therapy. This review focuses on the etiology, pathogenesis and morphological CT features of pulmonary calcifications. A knowledge of the technical aspects of CT imaging is required to verify calcifications and avoid pitfalls.

  View details for PubMedID 8927723

• Pulmonary calcifications. CT assessment and differential diagnosis RADIOLOGE Henk, C. B., Liskutin, J., Fleischmann, D., Mostbeck, G. H. 1996; 36 (7): 534-542

  View details for Web of Science ID A1996VA39700002

• Computed tomography in AIDS-related thoracic diseases RADIOLOGE Bankier, A. A., Fleischmann, D., Kontrus, M., WIESMAYR, M. N., Herold, C. J. 1996; 36 (7): 543-549

  View details for Web of Science ID A1996VA39700003

• [Computerized tomography of AIDS associated thoracic diseases]. Der Radiologe Bankier, A. A., Fleischmann, D., Kontrus, M., WIESMAYR, M. N., Herold, C. J. 1996; 36 (7): 543-549

  Abstract

  Pulmonary infections and tumors are a major cause of death in patients with AIDS. The combination of clinical, radiological, laboratory, and pathohistological data helps to narrow the spectrum of differential diagnoses or even allows a specific diagnosis in many patients. Nevertheless, an accurate diagnosis should be obtained as soon as possible during the clinical course of the illness to initiate treatment in time. Computed tomography (CT) has proven to provide promising results in the diagnosis of AIDS-related thoracic diseases. The aim of this paper was to demonstrate the diagnostic capacities of CT in the context of particular AIDS-related thoracic pathologies. Additional information on the spectrum of pathological agents and on differential diagnostic signs is summarized.

  View details for PubMedID 8927724

• [Spiral-CT [corrected] in chronic lung thromboembolism. Der Radiologe Kontrus, M., Bankier, A. A., Fleischmann, D., Winkelbauer, F. W., Klepetko, W., Lang, I., WIESMAYR, M. N., Herold, C. J. 1996; 36 (6): 496-502

  Abstract

  Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare result of recurrent pulmonary embolism and is treated by pulmonary thromboendarterectomy. Knowledge of the exact location of the thrombi is necessary in planning this operation. To date, pulmonary, angiography is the diagnostic imaging gold standard. Since the introduction of spiral CT excellent vascular opacification of the pulmonary arteries has become feasible, and thrombi in the pulmonary arteries can be visualized directly. Spiral CT is superior to angiography in demonstrating thrombi in the central pulmonary arteries, whereas angiography proves superior to CT in the evaluation of abnormalities within segmental arteries. The sensitivity of spiral CT in confirming the diagnosis of CTEPH is reported to be more than 90%. According to the literature and based on our own results, the decision concerning operability is possible on the basis of spiral CT images in more than 80% of patients with CTEPH. Spiral CT as a non-invasive tool may be used for CTEPH screening, for postoperative follow-up after pulmonary thrombendarterectomy and, combined with pulmonary angiography, to optimize operation planning.

  View details for PubMedID 8767120

• Diagnosis of pulmonary embolism using spiral-CT RADIOLOGE Fleischmann, D., Kontrus, M., Bankier, A. A., WIESMAYR, M. N., JanataSchwatczek, K., Herold, C. J. 1996; 36 (6): 489-495

  View details for Web of Science ID A1996UW82900005

• Spiral CT in patients with chronic thromboembolic lung disease RADIOLOGE Kontrus, M., Bankier, A. A., Fleischmann, D., Winkelbauer, F. W., Klepetko, W., Lang, I., WIESMAYR, M. N., Herold, C. J. 1996; 36 (6): 496-502

  View details for Web of Science ID A1996UW82900006

• Bronchial wall thickness: Appropriate window settings for thin-section CT and radiologic-anatomic correlation RADIOLOGY Bankier, A. A., Fleischmann, D., Mallek, R., Windisch, A., Winkelbauer, F. W., Kontrus, M., Havelec, L., Herold, C. J., Hubsch, P. 1996; 199 (3): 831-836

  Abstract

  To analyze the influence of computed tomographic (CT) window settings on bronchial wall thickness and to define appropriate window settings for its evaluation.Three inflation-fixed lungs were scanned with a section thickness of 1.5 mm by using a high-spatial-frequency algorithm. Wall thickness in 10 bronchial specimens was measured with planimetry. Window centers were altered in a range of -200 to -900 HU and window widths in a range of 400-1,500 HU. Relative and absolute differences between CT and planimetric values were calculated. CT and planimetric measures were correlated. Inter- and intraobserver variabilities were determined.Window widths less than 1,000 HU resulted in a substantial overestimation of bronchial wall thickness, whereas widths greater than 1,400 HU resulted in an underestimation of bronchial wall thickness. There was no interaction between "width" and "center" regarding their influence on bronchial walls (F = 0.23; P = .99). Correlation between CT and planimetry was statistically significant (r = .85; P = .0001). Differences between the two observers were not statistically significant; results of the measurements of the two observers correlated well (r = .97; P = .001).Bronchial wall thickness on thin-section CT scans should be evaluated with window centers between -250 and -700 HU and with window widths greater than 1,000 HU. Other than window settings, notably window widths less than 1,000 HU, can lead to substantial artificial thickening of bronchial walls.

  View details for Web of Science ID A1996UL52600043

  View details for PubMedID 8638013

• [Spiral CT in acute pulmonary embolism]. Der Radiologe Fleischmann, D., Kontrus, M., Bankier, A. A., WIESMAYR, M. N., Janata-Schwatczek, K., Herold, C. J. 1996; 36 (6): 489-495

  Abstract

  Pulmonary embolism is a frequent and potentially life-threatening event with uncharacteristic clinical manifestations. Diagnosis is commonly established by ventilation/perfusion scintigraphy and pulmonary angiography. Both methods, however, carry substantial drawbacks. Therefore, clinicians claim that there is a need for an accurate and non-invasive diagnostic modality. Spiral CT of the pulmonary arteries is a recent modality, that allows reliable visualization of emboli in pulmonary arteries up to fourth-order branches. This paper reviews the technical aspects, typical findings and diagnostic pitfalls of this recent technique. The potential role of spiral CT in the screening of patients with suspected pulmonary embolism is discussed and selected cases are presented.

  View details for PubMedID 8767119

• [Radiological diagnosis of emphysema prior to volume-reduction surgery]. Wiener medizinische Wochenschrift Kontrus, M., Bankier, A. A., Fleischmann, D., Herneth, A., Herold, C. J. 1996; 146 (23): 587-591

  Abstract

  Conventional chest X-ray and computed tomography as the main diagnostic tools are demonstrated with their possibilities in the diagnosis of emphysema. They were correlated with lung function tests and pathology in literature. Volume reduction surgery as a new operation technique for patients with advanced emphysema needs different radiologic evaluation. The radiologic possibilities for evaluation of operability of these patients and for operation planning will be discussed.

  View details for PubMedID 9064919

• Lung metastases EUROPEAN RADIOLOGY Herold, C. J., Bankier, A. A., Fleischmann, D. 1996; 6 (5): 596-606

  Abstract

  The lungs are among the most prominent target organs for metastatic disease. Most frequently, lung metastases originate from cancers of the head and neck, breast, stomach, pancreas, kidney, bladder, the male and female genitourinary tract, and sarcomas. Plain chest radiography is typically the modality used for detection and therapeutic monitoring; however, the use of CT for these purposes is becoming more frequent. Currently, spiral CT appears to be the most sensitive imaging technique in the identification of metastases, because it detects a higher number of pulmonary nodules compared to other techniques. Pulmonary metastatic disease manifests itself by the presence of pulmonary nodules, lymphangitic carcinomatosis, endobronchial tumors, and pleural involvement. Nevertheless, the differential diagnosis is an important consideration, particularly in patients with solitary pulmonary nodules, systemic disorders, and signs or symptoms indicative of infection. The role of the radiologist involves the identification of metastatic disease, monitoring of response to therapy, and the use of invasive procedures when the differential diagnosis indicates the need for biopsy and histopathologic proof. The radiologist must be aware of the impact of his diagnosis on patient management and should be familiar with oncologic strategies as well as the terminology used to characterize tumor response. In future, the role of imaging may further expand due to the increased sensitivity in lesion detection, increased specificity in lesion (tissue) characterization using MR imaging imaging, and reduced radiation exposure.

  View details for Web of Science ID A1996VM42400002

  View details for PubMedID 8934121

• DISCRETE LUNG INVOLVEMENT IN SYSTEMIC LUPUS-ERYTHEMATOSUS - CT ASSESSMENT RADIOLOGY Bankier, A. A., Kiener, H. P., WIESMAYR, M. N., Fleischmann, D., Kontrus, M., Herold, C. J., GRANINGER, W., Hubsch, P. 1995; 196 (3): 835-840

  Abstract

  To study the computed tomographic (CT) appearance of early lung involvement in systemic lupus erythematosus (SLE).In a prospective study, 48 patients with serologically confirmed SLE but no prior clinical evidence of lung involvement underwent chest radiography, CT, and lung function tests. Radiographs and CT scans were compared, and CT scans were evaluated for signs suggestive of parenchymal and pleural disease. Extent and distribution of disease were determined. CT findings were correlated with clinical and functional data.Of 45 patients with normal chest radiographs, 17 (38%) had abnormal CT findings. Extent of disease was statistically significantly correlated with duration of clinical history (r = .93) and decreased single-breath diffusing capacity for carbon monoxide (r = .8) and ratio of forced expiratory volume in 1 second to forced vital capacity (r = .77).CT is superior to chest radiography for detection of functionally relevant pulmonary disease and is an important adjunct in early assessment of SLE.

  View details for Web of Science ID A1995RQ24300041

  View details for PubMedID 7644652

• AUTOMATIC PATIENT-INSTRUCTION DEVICES IN THIN-SECTION CT OF THE THORAX - IMPACT ON IMAGE QUALITY 1994 Radiological-Society-of-North-America Scientific Assembly Bankier, A. A., Fleischmann, D., KANTENDORFER, K., WIESMAYR, M. N., Kontrus, M., Hubsch, P., Herold, C. J. RADIOLOGICAL SOC NORTH AMERICA. 1995: 841–44

  Abstract

  To determine what influence automatic patient-instruction (API) devices have on image quality of chest computed tomographic (CT) scans and whether the qualitative outcome justifies their routine use.Thin-collimation CT scans of two age- and sex-matched groups of 64 patients each were evaluated prospectively for the presence of breathing artifacts and for concomitant deterioration of image quality. Breathing commands in group 1 were given with the API device and in group 2 with technologist-performed patient instruction. Cardiac motion artifacts were not evaluated. The frequency of scans repeated owing to breathing artifact was determined.Image quality was worse in group 1 compared with that of group 2. The percentage of scans repeated was higher with API (38%) than without API (16%).API devices cannot be recommended for thin-section CT of the thorax. The large number of scans that must be repeated leads to a considerable increase in patient irradiation, scanning time, and cost.

  View details for Web of Science ID A1995RQ24300042

  View details for PubMedID 7644653

• ULTRASOUND IMAGING FOR STELLATE GANGLION BLOCK - DIRECT VISUALIZATION OF PUNCTURE SITE AND LOCAL-ANESTHETIC SPREAD - A PILOT-STUDY REGIONAL ANESTHESIA Kapral, S., Krafft, P., Gosch, M., Fleischmann, D., Weinstabl, C. 1995; 20 (4): 323-328

  Abstract

  Stellate ganglion block (SGB) inhibits sympathetic innervation and is a common treatment for reflex sympathetic dystrophy. During the positioning of the needle, there is a risk of injury to the adjacent structures. The aim of the study was to develop an ultrasonographic imaging technique for the performance of SGB.Twelve patients (ASA I-II) underwent SGB first by using the blind standard technique (group A: 8 mL bupivacaine 0.25%) and a second time by using an ultrasonographic imaging technique (group B: 5 mL bupivacaine 0.25%). In group B a 10 MHz ultrasound scanning probe was used to identify the anatomic structures and to guide the needle toward the transverse process of C6.Stellate ganglion block was satisfactory in 11 of 12 attempts by the blind technique. Ultrasonographic guidance (group B) resulted in a complete block in all patients. Onset of block was observed within 10 minutes in only 10 of 12 group A patients, while all patients in group B exhibited an adequate block after 10 minutes. During the imaging technique, the needle was inserted to an average depth of 22 +/- 3 mm and the injection of 5 mL bupivacaine resulted in an anesthetic depot with a mean diameter of 14 +/- 3 mm. Distance from the depot to the vagal nerve was 5 +/- 3 mm and 5 +/- 4 mm to the root of C6. All patients (n = 4) with a distance of < 1 mm between anesthetic depot and the root of C6 developed paresthesia within the corresponding cutaneous segment. Blind technique resulted in hematoma formation in three study patients, with no hematoma occurring during imaging technique.Ultrasonographic guided SGB may improve safety and allows the visualization of the local anesthetic depot. Studying the local anesthetic spread might allow the avoidance of side effects as well as typical complications of SGB.

  View details for Web of Science ID A1995RL21700008

  View details for PubMedID 7577781

• UPDATE - ABDOMINAL TUBERCULOSIS - UNUSUAL FINDINGS ON CT CLINICAL RADIOLOGY Bankier, A. A., Fleischmann, D., WIESMAYER, M. N., Putz, D., Kontrus, M., Hubsch, P., Herold, C. J. 1995; 50 (4): 223-228

  Abstract

  To update our knowledge of abdominal tuberculosis as manifested on computed tomography (CT), we reviewed the CT scans of 12 patients with proven abdominal tuberculosis. The nature, range and extent of abdominal involvement was determined. The CT findings were compared to those reported in the literature. The aetiologic agent was Mycobacterium tuberculosis in all patients. One patient had an increased risk because of AIDS. In nine patients, tuberculosis was limited to the abdomen, and three patients had previously unknown thoracic tuberculous disease. Characteristic features in our patients included low density ascites and uncommon patterns of adenopathy. Findings reported to be typical in abdominal tuberculosis were present in only five of our 12 patients. Unusual findings in our patients included solitary and multiple pelvic, adrenal, splenic and hepatic lesions. In six of 12 patients, those findings mimicked malignancy. We conclude that knowledge and early recognition of these unusual manifestations of abdominal tuberculosis should help to optimize clinical management of the disease and avoid misdiagnosis.

  View details for Web of Science ID A1995QT14400004

  View details for PubMedID 7729118

• POSITION OF JUGULAR OXYGEN-SATURATION CATHETER IN PATIENTS WITH HEAD TRAUMA - ASSESSMENT BY USE OF PLAIN FILMS AMERICAN JOURNAL OF ROENTGENOLOGY Bankier, A. A., Fleischmann, D., Windisch, A., Germann, P., PETRITSCHEK, W., WIESMAYR, M. N., Hubsch, P. 1995; 164 (2): 437-441

  Abstract

  The purpose of this study was to establish a plain radiographic technique for the assessment of the position of a jugular oxygen saturation catheter in patients with head trauma.In the experimental study, jugular oxygen saturation catheters were introduced into the internal jugular veins of four cadavers. Correct positioning of the catheter tips was monitored by CT. Concurrent anteroposterior radiographs of the skulls were obtained with the tubes angled in a transverse plane and in a sagittal plane at intervals of 5 degrees and within a total range of 70 degrees for each plane. Three radiologists judged the visibility of the catheter tips and measured the distance of the catheter tips to previously determined bony landmarks of the skull. Then, preliminary radiologic criteria for correct positioning of the catheters were defined. In the clinical study, we prospectively evaluated radiographs for 32 patients who received jugular oxygen saturation catheters. Eleven patients had digital radiographs done, and 21 patients had radiographs with a conventional screen film system done. Radiographs were analyzed for consistency of findings with the experimental results and for consistency of the suspected catheter position with laboratory data.Results of the cadaveric study showed that catheter position is best assessed on strict anteroposterior radiographs with the orbitomeatal-basal line perpendicular to the plane of the film. A correctly positioned catheter tip should lie cranial to a line extending from the atlantooccipital joint space and caudal to the lower margin of the orbit. The catheter tip also should lie cranial to a line connecting the tips of the mastoid processes, with a catheter tip-to-line distance averaging 20% of the overall distance between the tips of the mastoid processes. According to these criteria, the catheter was properly positioned in 26 of 32 patients. In three patients, the catheter obviously was improperly positioned. Catheter position was equivocal in three other patients; in two of these patients, the catheter was looped within the internal jugular vein. Whereas for all 26 patients with properly positioned catheters values for jugular venous oxygen saturation were congruent with other laboratory data, incongruent saturation values were recorded for five of the six patients with equivocally or obviously improperly positioned catheters.Accurate assessment of the position of a jugular oxygen saturation catheter can be made by use of specific bony landmarks seen on anteroposterior radiographs of the skull.

  View details for Web of Science ID A1995QC79400033

  View details for PubMedID 7839985

• [Right aortic arch simulates mediastinal tumor: diagnosis with spiral CT]. Aktuelle Radiologie Bankier, A., Fleischmann, D., WIESMAYR, M., Hübsch, P. 1995; 5 (1): 70-72

  Abstract

  We report the case of a patient with right aortic arch (type III) mimicking a mediastinal tumor. We discuss the radiological findings together with their embryologic correlations, and emphasize the role of spiral-CT in the acquisition of imaging data under difficult diagnostic conditions.

  View details for PubMedID 7888437

• [Candida glabrata pneumonia in a non-immunosuppressed patient: diagnostic imaging with digital luminescence radiography and CT]. Aktuelle Radiologie Bankier, A., Fleischmann, D., WIESMAYR, M., Laczika, K., Hübsch, P. 1994; 4 (4): 192-194

  Abstract

  Pneumonias caused by Candida glabrata are extremely rare and occur almost exclusively in immunocompromised patients. We report an atypical case of Candida glabrata pneumonia in a non-immunocompromised patient and describe the imaging findings on digital radiography and computed tomography.

  View details for PubMedID 7918708

• [Percutaneous drainage of intra-abdominal abscesses in Crohn disease]. Aktuelle Radiologie WIESMAYR, M., Bankier, A., Fleischmann, D., Karnel, F. 1994; 4 (4): 184-187

  Abstract

  The majority of abcesses associated with Crohn's disease require surgical treatment. Since the postoperative rate of complications is high, particular care is needed in the choice of surgical therapy for patients with Crohn's disease. The interventional radiological method of percutaneous abcess drainage provides the surgeon with an alternative technique suitable both for the curative treatment of simple abcesses and for the palliation of complicated abcesses prior to elective surgical treatment. We have retrospectively analysed the drainage protocols, operation reports, and case histories of 7 patients with intra-abdominal abcesses in Crohn's disease. The results of our study emphasise the excellent clinical value of PAD in the treatment of abcesses associated with Crohn's disease.

  View details for PubMedID 7522578

• [Bronchiolitis obliterans accompanied by organizing pneumonia: radiologic diagnosis in a case of a 22-year-old female]. Aktuelle Radiologie Bankier, A., Fleischmann, D., Baldt, M., Hübsch, P. 1994; 4 (1): 39-40

  Abstract

  Case report of a 22-year old patient with most severe idiopathic bronchiolitis obliterans and organising pneumonia. We discuss the diagnostic algorithm and emphasise the role of CT.

  View details for PubMedID 8136390

• RAPID SCREENING FOR BACTERIURIA IN PREGNANCY INFECTION GRANINGER, W., Fleischmann, D., Schneeweiss, B., Aram, L., Stockenhuber, F. 1992; 20 (1): 9-11

  Abstract

  We evaluated a bioluminescence assay as a screening test for the detection of bacteriuria in pregnancy. A total of 1,000 urine specimens from a randomly selected group of pregnant women undergoing prenatal surveillance was investigated. Sequential dilution of urine specimens on CLED agar plates served as a reference method. Set against the reference group, bioluminescence screening scored a 93% sensitivity, a 78% specificity and a 99% predictive accuracy for negative results. All urine specimens were also analysed chemically for the presence of nitrite and leucocyte esterase by dip sticks. Dip sticks proved to be insufficient because of poor sensitivities of 54% and 59%, respectively. The bioluminescence assay is an effective, time- as well as labor-saving but questionably cost-effective method for the detection of bacteriuria in pregnancy.

  View details for Web of Science ID A1992HF59700002

  View details for PubMedID 1563815

• In vitro uptake 153gadolinium and gadolinium complexes by hyaline articular cartilage. European journal of radiology Engel, A., Hamilton, G., Hajek, P., Fleischmann, D. 1990; 11 (2): 104-106

  Abstract

  This in vitro study evaluated whether Gadolinium (Gd) penetrates into hyaline cartilage and would be incorporated into vital chondrocytes. Hyaline joint cartilage of rabbits was exposed to radioactive 153GdCl3 and to a radioactive 153Gd-DTPA-BSA-complex (DTPA, diethylene-triaminepentaacetic acid; BSA, bovine serum albumine). In addition an exchange experiment with radioactive 153GdCl3 versus Gd-DTPA-di-N-methylglucamine (Magnevist) was performed. Incorporation of 153GdCl3 into neuroblastoma cells, connective tissue cells and chondrocytes was tested. The results showed that the depth and extent of incorporation of Gd depends on the molecular mass and time of exposure. 153Gd-DTPA-BSA complexes exhibited an incorporation rate of maximal 11% +/- 2.8% up to the middle third of the cartilage within 24 h with almost no incorporation (2 +/- 1.9%) for the deep layer. The exchange experiment revealed no uptake of Gd for the deep layer. The maximal incorporation rate of 153GdCl3 into vital chondrocytes was 6.3%. These data indicate that under the condition of MR-arthrography, Gd-DTPA-di-N-methylglucamine will not be absorbed into the deep layers of hyaline cartilage and will not be incorporated into vital chondrocytes.

  View details for PubMedID 1701389

• Semiautomated Characterization of Carotid Artery Plaque Features From Computed Tomography Angiography to Predict Atherosclerotic Cardiovascular Disease Risk Score. Journal of computer assisted tomography Zhu, G. n., Li, Y. n., Ding, V. n., Jiang, B. n., Ball, R. L., Rodriguez, F. n., Fleischmann, D. n., Desai, M. n., Saloner, D. n., Gupta, A. n., Saba, L. n., Hom, J. n., Wintermark, M. n. ; 43 (3): 452–59

  Abstract

  To investigate whether selected carotid computed tomography angiography (CTA) quantitative features can predict 10-year atherosclerotic cardiovascular disease (ASCVD) risk scores.One hundred seventeen patients with calculated ASCVD risk scores were considered. A semiautomated imaging analysis software was used to segment and quantify plaque features. Eighty patients were randomly selected to build models using 14 imaging variables and the calculated ASCVD risk score as the end point (continuous and binarized). The remaining 37 patients were used as the test set to generate predicted ASCVD scores. The predicted and observed ASCVD risk scores were compared to assess properties of the predictive model.Nine of 14 CTA imaging variables were included in a model that considered the plaque features in a continuous fashion (model 1) and 6 in a model that considered the plaque features dichotomized (model 2). The predicted ASCVD risk scores were 18.87% ± 13.26% and 18.39% ± 11.6%, respectively. There were strong correlations between the observed ASCVD and the predicted ASCVDs, with r = 0.736 for model 1 and r = 0.657 for model 2. The mean biases between observed ASCVD and predicted ASCVDs were -1.954% ± 10.88% and -1.466% ± 12.04%, respectively.Selected quantitative imaging carotid features extracted from the semiautomated carotid artery analysis can predict the ASCVD risk scores.

  View details for PubMedID 31082951

• Endovascular Aortic Repair After Proximal Stent Graft Migration of a Modified Frozen Elephant Trunk. Innovations (Philadelphia, Pa.) Dalal, A. R., Pedroza, A. J., Iwakoshi, S. n., Lee, J. T., Fleischmann, D. n., Watkins, A. C. ; 15 (2): 169–72

  Abstract

  We describe the endovascular repair for a proximal endograft migration following a modified frozen elephant trunk (mFET) repair for a retrograde type A dissection (retro-A AD). A 40-year-old man presented with a type B aortic dissection that progressed to a retro-A AD. He was emergently taken to the operating room for an mFET repair. Computed tomography (CT) angiogram on the day of discharge revealed that the proximal end of the endograft migrated through the primary intimal tear resulting in obstruction of true lumen flow. The patient returned to the catheterization lab for endovascular repair utilizing a through-and-through wire to extend the endograft proximally and a left carotid-subclavian artery bypass. This complication highlights the importance of postoperative CT surveillance and the endovascular technique utilized to restore aortic true lumen flow.

  View details for DOI 10.1177/1556984520902839

  View details for PubMedID 32352908