Eric Olcott
Professor of Radiology (Veterans Affairs), Emeritus
Administrative Appointments
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Chief, Radiology Service, Veterans Affairs Palo Alto Health Care System (2006 - 2012)
Current Research and Scholarly Interests
Body imaging utilizing CT, ultrasound and MRI. Imaging of appendicitis. Imaging of pancreatic and biliary malignancies. Imaging of trauma. Magnetic resonance angiography.
2023-24 Courses
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Independent Studies (6)
- Directed Reading in Radiology
RAD 299 (Aut, Win, Spr, Sum) - Early Clinical Experience in Radiology
RAD 280 (Aut, Win, Spr, Sum) - Graduate Research
RAD 399 (Aut, Win, Spr, Sum) - Medical Scholars Research
RAD 370 (Aut, Win, Spr, Sum) - Readings in Radiology Research
RAD 101 (Aut, Win, Spr, Sum) - Undergraduate Research
RAD 199 (Aut, Win, Spr, Sum)
- Directed Reading in Radiology
All Publications
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The Borderline-Size Appendix: Grayscale, Color Doppler, and Spectral Doppler Findings That Improve Specificity for the Sonographic Diagnosis of Acute Appendicitis.
Ultrasound quarterly
2020
Abstract
Diagnostic criteria for acute appendicitis using graded compression sonography have been well established based on the maximum outer diameter (MOD) of the appendix, with MOD values of <6 mm nearly always indicating normal appendices and MOD values of >8 mm nearly always indicating appendicitis. However, the "borderline-size" appendix, meaning one whose MOD lies between these ranges (ie, an appendix with MOD of 6-8 mm), presents a diagnostic dilemma because appendices in this size range are neither clearly normal nor abnormal when diagnosis is based on the MOD alone; accordingly, such borderline MOD values are diagnostically equivocal, and sonographic diagnosis must rely on sonographic findings other than the MOD. The goal of this review was to examine the additional sonographic findings that can add specificity and help enable an accurate diagnosis to be made in patients with borderline-size appendices.
View details for DOI 10.1097/RUQ.0000000000000536
View details for PubMedID 33136933
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Hyperechoic Periappendiceal Fat: Evaluation of Criteria for Improving Specificity in the Sonographic Diagnosis of Appendicitis in Pediatric Patients.
Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine
2020
Abstract
OBJECTIVES: To test the hypothesis that abutting and encasing types of hyperechoic periappendiceal fat are specific sonographic indicators of appendicitis in pediatric patients, including individuals with maximum outer diameters (MODs) of 6 to 8mm in whom diagnosis by the MOD alone is known to be equivocal.METHODS: Appendiceal sonograms of 271 consecutive pediatric patients were retrospectively evaluated for hyperechoic periappendiceal fat (globular, ≥1.0cm; categorized as type 0, none; type 1, "abutting," encompassing <180° of the appendiceal circumference; or type 2, "encasing," encompassing 180° or more of the appendiceal circumference) and the MOD. Histopathologic and medical records constituted reference standards. Statistical methods included the binomial distribution, logistic regression, a receiver operating characteristic analysis, and the exact McNemar test.RESULTS: All patients with hyperechoic fat and 105 of 107 patients with appendicitis had MODs of 6mm or greater. The MOD and fat types 1 and 2 each were significantly associated with appendicitis in the univariable regression. The MOD and fat type 1 were independently associated with appendicitis in multivariable regression (odds ratio, 24.97; P = .034; and odds ratio, 5.35; P<.001, respectively). Specificities of an MOD of 6 to 8mm and an MOD of 6mm or greater alone were 89.0% (95% confidence interval, 83.2%-93.4%); these increased to 100.0% each (95% confidence interval, 97.8%-100.0%; P<.001) when combined with fat types 1, 2, and either 1 or 2 as diagnostic criteria, with positive predictive values of 100.0%.CONCLUSIONS: Types 1 and 2 periappendiceal fat are specific indicators of appendicitis, and both improve specificity compared to the MOD. Importantly, they add specificity in diagnosing appendicitis in patients with diagnostically equivocal MODs of 6 to 8mm.
View details for DOI 10.1002/jum.15399
View details for PubMedID 32697409
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Ileocolic vascular curvature: a new CT finding of cecal volvulus.
Abdominal radiology (New York)
2020
Abstract
PURPOSE: To evaluate the diagnostic performance of a proposed new CT observation in cecal volvulus, marked hook-like curvature of ileocolic vessels termed "ileocolic vascular curvature."METHODS: Contrast-enhanced CT scans of 14 patients with diagnoses of cecal volvulus on original CT reports were compared with scans of 40 control patients with dilated cecum but no cecal volvulus on original CT reports, accrued consecutively from January, 2006 through July, 2017. Two independent blinded readers retrospectively evaluated scans for cecal dilatation, ileocolic vascular curvature and seven previously reported CT features of cecal volvulus. Statistical methods included the exact binomial distribution to define 95% confidence intervals (95% CIs), logistic regression, receiver operating characteristic analysis, and the exact McNemar test. Pathology reports and clinical records served as reference standards.RESULTS: All patients had abdominal pain and cecal distension. All 14 patients with CT diagnoses of cecal volvulus, and no control patients, had cecal volvulus by reference standards. Ileocolic vascular curvature and ectopic cecal location were the only features independently and significantly associated with cecal volvulus in multivariable regression (odds ratio 178, p=0.014, and 63, p=0.013, respectively) and also the only features with both sensitivity (12/14 [85.7%, 95% CI 57.2-98.2%] and 13/14 [92.9%, 95% CI 66.1-99.8%], respectively) and specificity (40/40 [100.0%, 95% CI 91.2-100.0%] and 38/40 [95.0%, 95% CI 83.1-99.4%], respectively) that differed significantly from 50.0%.CONCLUSIONS: Ileocolic vascular curvature was independently and significantly associated with cecal volvulus and exhibited both substantial sensitivity and substantial specificity for cecal volvulus, and thus is potentially a valuable new CT finding of cecal volvulus.
View details for DOI 10.1007/s00261-020-02491-w
View details for PubMedID 32221671
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Hyperechoic Abdominal Fat A Sentinel Sign of Inflammation
ULTRASOUND QUARTERLY
2019; 35 (2): 186–94
View details for DOI 10.1097/RUQ.0000000000000387
View details for Web of Science ID 000474131600016
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Commentary on the article "Luminal obstruction in uncomplicated appendicitis: detection with sonography and potential clinical implications" Reply
JOURNAL OF CLINICAL ULTRASOUND
2019; 47 (3): 121
View details for DOI 10.1002/jcu.22706
View details for Web of Science ID 000460660200003
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Luminal obstruction in uncomplicated appendicitis: Detection with sonography and potential clinical implications
JOURNAL OF CLINICAL ULTRASOUND
2019; 47 (3): 113–19
View details for DOI 10.1002/jcu.22655
View details for Web of Science ID 000460660200001
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Reply by Author.
Journal of clinical ultrasound : JCU
2019
View details for PubMedID 30730560
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Groove pancreatitis: a clinical and imaging overview.
Abdominal radiology (New York)
2019
Abstract
Groove or paraduodenal pancreatitis is an uncommon fibroinflammatory form of pancreatitis involving the anatomic space of the pancreatic groove located between the C-loop of the duodenum and the head of the pancreas. Although in some patients there are distinctive clinical and imaging features of groove pancreatitis (GP), there is often significant overlap with other infiltrative processes involving the pancreatic groove such as pancreatic ductal adenocarcinoma or duodenal carcinoma. In this review, we summarize the most distinctive clinical and imaging aspects of GP and highlight some important distinguishing features that may aid in differentiating malignant lesions involving the pancreatic groove.
View details for DOI 10.1007/s00261-019-02239-1
View details for PubMedID 31559471
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Luminal obstruction in uncomplicated appendicitis: Detection with sonography and potential clinical implications.
Journal of clinical ultrasound : JCU
2018
Abstract
PURPOSE: To determine the frequency of luminal obstruction on appendiceal graded compression sonography (US) in patients with uncomplicated appendicitis and test the hypothesis that this frequency is similar to the failure rates of primary antibiotic therapy for uncomplicated appendicitis when treatment selection is based on CT findings.METHODS: Sonograms of 150 consecutive patients with appendicitis diagnosed on ultrasound (US) and proven histopathologically were retrospectively evaluated; 114 (76.0%) had uncomplicated appendicitis, that is, appendicitis without gangrene or perforation, and were evaluated for appendicolithiasis and lymphoid hyperplasia using previously published sonographic criteria, and for luminal obstruction.RESULTS: Of the 114 patients with uncomplicated appendicitis, US demonstrated no luminal obstruction in 74 (64.9%) and luminal obstruction in 40 (35.1%, P =.018), the latter including 16 (40.0%) with lymphoid hyperplasia and 24 (60.0%, P =.074) with appendicolithiasis.CONCLUSIONS: US demonstrated luminal obstruction in 35.1% of patients with uncomplicated appendicitis, similar to the published failure rates of antibiotic therapy when treatment selection is based on CT. This confirms the hypothesis, supporting the possibility that undiagnosed luminal obstruction may account for treatment failures when patients are selected by CT for primary antibiotic therapy, and suggests a role for US in selecting patients without luminal obstruction for antibiotic therapy.
View details for PubMedID 30350372
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Hyperechoic Abdominal Fat: A Sentinel Sign of Inflammation.
Ultrasound quarterly
2018
Abstract
One of the most useful sonographic signs of acute abdominal inflammation is the identification of increased echogenicity of the surrounding fat. Hyperechoic fat results from vasodilation and edema extending from an adjacent source of infection or inflammation. These changes are mediated by such factors such as bradykinin, histamine, and various cytokines. The recognition of hyperechoic fat on sonography may be an important indicator of the primary source of pathology. In addition, it often reflects a more advanced degree of transmural pathology, such as "walled-off" perforation of a hollow viscus. This pictorial essay will present a variety of examples of hyperechoic inflamed fat involving different abdominal organs and will illustrate the diagnostic value of this finding.
View details for PubMedID 30300322
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Sonography of the Cecum: Gateway to the Right Lower Quadrant
ULTRASOUND QUARTERLY
2018; 34 (3): 133–40
View details for DOI 10.1097/RUQ.0000000000000332
View details for Web of Science ID 000443612000006
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Sonography of the Cecum: Gateway to the Right Lower Quadrant.
Ultrasound quarterly
2018; 34 (3): 133–40
Abstract
Sonography of the cecum has come of age largely as a consequence of the successful evolution of appendiceal sonography as a useful tool in the evaluation of patients with right lower-quadrant pain. At some medical centers, graded-compression sonography (GCS) has become the initial imaging study of choice in the assessment of these individuals. The cecum serves as a helpful anatomic landmark for localization of the appendix in these examinations-providing a sonographic starting point in the search for the appendix. During GCS, primary pathology within the cecum itself can become evident, including a variety of processes, such as infectious, inflammatory, or neoplastic disorders, whose presentations commonly mimic that of appendicitis. The accurate diagnosis of cecal abnormalities and their differentiation from acute appendicitis play valuable roles in the management of affected patients because the options for further workup and subsequent treatment vary greatly according to the diagnosis at hand. Additionally, the compressed cecum often becomes an acoustic window into the right lower quadrant, revealing pathology apart from the appendix within the right iliac fossa. The purpose of this pictorial essay is to highlight the importance and value of performing a careful evaluation of the cecum during GCS of patients with suspected appendicitis and to review the differential diagnosis and imaging findings of primary cecal abnormalities whose clinical presentations can mimic that of acute appendicitis.
View details for PubMedID 29346264
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Radiologic Evaluation of Intrahepatic Cholangiocarcinoma Perineural Invasion
AMERICAN JOURNAL OF ROENTGENOLOGY
2018; 210 (3): W129
View details for PubMedID 29469628
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Extrapancreatic perineural invasion in pancreatic adenocarcinoma
ABDOMINAL RADIOLOGY
2018; 43 (2): 323–31
Abstract
Pancreatic ductal adenocarcinoma continues to be a highly lethal disease, despite advances in modern medicine. Curative surgical options continue to carry significant morbidity and offer little improvement in overall 5-year survival. Currently, imaging plays an essential role in the pre-operative evaluation of patients who are undergoing evaluation for resection. However, some pancreatic cancers have particularly aggressive biology, despite appearing resectable by conventional imaging criteria. Imaging biomarkers that serve as surrogates for tumors with such aggressive phenotype have been recently described, namely duodenal invasion and extrapancreatic perineural invasion. In this pictorial review, we will summarize key concepts of extrapancreatic perineural invasion, describe its association with a poor prognosis, and highlight the role of imaging in its detection.
View details for PubMedID 28980054
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Delayed diagnosis of celiac stenosis causing hepatic transplant ischaemic necrosis: diagnosis by spectral Doppler findings.
BJR case reports
2017; 3 (1): 20150210
Abstract
Following presentation with abnormal liver function enzymes, confusion and fatigue, a 65-year-old male with alcoholic cirrhosis underwent spectral Doppler sonography that showed tardus parvus-like morphology in the main and left hepatic arteries, although peak systolic velocities and resistive indices remained normal. The patient's continuing clinical symptoms prompted CT angiography, which demonstrated an unexpected, haemodynamically significant stenosis of the celiac artery. Although the stenosis was successfully stented and the hepatic arterial waveforms normalized, the transplanted liver had already undergone ischaemic necrosis, with resulting failure and the need for retransplantation. Recognition of abnormal waveforms, despite normal peak systolic velocities and resistive indices, with prompt definitive imaging evaluation of the arterial tree beyond just the main hepatic artery, may lead to the diagnosis of unexpected flow-limiting lesions in time to allow revascularization and thus prevent ischaemic transplant failure.
View details for DOI 10.1259/bjrcr.20150210
View details for PubMedID 30363311
View details for PubMedCentralID PMC6159272
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Anatomic Reasons for Failure to Visualize the Appendix With Graded Compression Sonography: Insights From Contemporaneous CT
AMERICAN JOURNAL OF ROENTGENOLOGY
2017; 209 (3): W128–W138
Abstract
The purpose of this study is to identify the anatomic locations of appendixes on CT when graded compression sonography fails to visualize the appendix.The study included 197 patients with suspected appendicitis whose appendixes were not visualized on graded compression sonography performed with typically used transducers of at least 10 MHz, who underwent CT within 48 hours following graded compression sonography, and who had available either pathologic examination following surgery or 6-week follow-up if surgery was not performed. Appendixes were retrospectively localized using four transverse quadrants (including the posteromedial quadrant) centered on the ileocecal valve and projected vertically, the craniocaudal level relative to the iliac crests, and the depth of the appendix as measured from the surface of the skin. Data were assessed using the Fisher exact test, t test, multinomial test, binomial distribution, ANOVA, and linear regression.Appendixes were most frequently located in the posteromedial quadrant (123 of 197 patients [62.4%]; 95% CI, 55.3-69.2%) at a statistically significantly greater frequency than that expected by chance (p < 0.00001). Appendixes were located above the iliac crests in 19.8% of patients (39/197; 95% CI, 14.5-26.1%) and at depths exceeding the penetration of typical transducers of at least 10 MHz in 19.3% of patients (38/197; 95% CI, 14.0-25.5%). All appendixes (95% CI, 98.1-100.0%) were located within the range of 6-MHz transducers.Appendixes that are not visualized on graded compression sonography are most frequently located in the posteromedial quadrant and are often located above the iliac crests or at depths too great for visualization with typically used transducers of at least 10 MHz. Accordingly, when the appendix is not visualized on graded compression sonography, targeted scanning of the posteromedial quadrant and the region above the iliac crests, and scanning with 6-MHz transducers, may enable visualization of the appendix and are recommended additions to scanning protocols.
View details for PubMedID 28829172
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Spectral Doppler Waveforms for Diagnosis of Appendicitis: Potential Utility of Point Peak Systolic Velocity and Resistive Index Values.
Radiology
2017: 162251-?
Abstract
Purpose To test the hypothesis that appendiceal spectral Doppler waveforms can distinguish patients with and patients without appendicitis. Materials and Methods In this retrospective study, Doppler waveforms were obtained from intramural appendiceal arteries identified with color Doppler imaging in 60% (93 of 155) of consecutive patients whose appendices were visualized at graded compression ultrasonography (US) performed for suspected appendicitis (53 male and 40 female; age, 1-56 years; mean, 14.5 years) over the 5-month period from November 2015 through March 2016. Point, non-angle-corrected peak systolic velocity (PSV) and resistive index (RI) values were compared between patients with and patients without appendicitis by utilizing histopathologically proven appendicitis and 6-week clinical follow-up as diagnostic reference standards. Data were assessed by using the Student t test, exact binomial distribution, two-sample test of proportions, and receiver operating characteristic analysis. Results Among the 93 patients, 36 (38.7%) had proven appendicitis (mean PSV, 19.7 cm/sec; mean RI, 0.69) and 57 patients (61.2%) did not (mean PSV, 7.1 cm/sec, P < .0001; mean RI, 0.50, P < .0001). The area under the receiver operating characteristic curve for the diagnosis of appendicitis was 0.97 (95% confidence interval [CI]: 0.95, 1.00) for PSV and 0.86 (95% CI: 0.78, 0.95; P = .011) for RI. Chosen discriminatory criteria of PSV greater than 10 cm/sec and RI greater than 0.65 yielded specificity for appendicitis of 94.7% and 96.5% with sensitivity of 88.9% and 63.9% (P = .013) and negative predictive value of 93.1% and 80.9% (P = .045), respectively. Original clinical graded compression US interpretations based on established US findings demonstrated specificity of 96.2% and sensitivity of 100.0%. Considering the subset of 20 patients whose maximum outer diameter measured 6-8 mm, the discriminatory criteria of PSV greater than 10 cm/sec and RI greater than 0.65 yielded specificity for appendicitis of 88.9% each, with sensitivity of 100.0% and 63.6% and negative predictive value of 100.0% and 66.6%, respectively. Conclusion In patients with visualized appendices at US, those with appendicitis exhibit significantly higher point PSV and point RI values than do patients without appendicitis and are distinguishable with high specificity by using a PSV greater than 10 cm/sec and an RI greater than 0.65 as diagnostic criteria. (©) RSNA, 2017.
View details for DOI 10.1148/radiol.2017162251
View details for PubMedID 28582634
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Sonographic Differentiation of Complicated From Uncomplicated Appendicitis Implications for Antibiotics-First Therapy
JOURNAL OF ULTRASOUND IN MEDICINE
2017; 36 (2): 269-277
Abstract
To evaluate sonographic findings as indicators of complicated versus uncomplicated appendicitis in the setting of known appendicitis, a necessary distinction in deciding whether to proceed with antibiotic therapy or with appendectomy.With Institutional Review Board approval and Health Insurance Portability and Accountability Act compliance, appendiceal sonograms of 119 patients with histopathologically proven appendicitis were retrospectively blindly reviewed to determine the presence or absence of the normally echogenic submucosal layer, the presence of mural hyperemia, periappendiceal fluid, appendicoliths, and hyperechoic periappendiceal fat and to determine the maximum outside diameter. Results were compared with the presence of complicated versus uncomplicated appendicitis on histopathologic examination and assessed by both univariate and mulitvariate logistic regression; confidence intervals (CIs) of proportions were assessed by the exact binomial test.Thirty-two (26.9%) of the 119 patients had complicated appendicitis, including 11 with gangrenous appendicitis without perforation and 21 with gangrenous appendicitis and perforation. Loss of the submucosal layer was the only independent significant indicator of complicated appendicitis in multivariate regression (P < .001) and provided sensitivity and specificity values of 100.0% (95% CI, 89.1%-100.0%) and 92.0% (95% CI, 84.1%-96.7%), respectively.Loss of the normally echogenic submucosal layer was the most useful sonographic finding for discriminating complicated from uncomplicated appendicitis, being the only finding independently and significantly associated with complicated appendicitis and, additionally, providing both high sensitivity and high specificity. This information may help a physician decide whether to proceed with antibiotic therapy or with appendectomy when treating a patient with appendicitis.
View details for DOI 10.7863/ultra.16.03109
View details for PubMedID 28039865
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Capsule Ultrasound Device: Characterization and Testing Results
IEEE. 2017
View details for Web of Science ID 000416948401038
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Delayed diagnosis of celiac stenosis causing hepatic transplant ischaemic necrosis: diagnosis by spectral Doppler findings
BJR CASE REPORTS
2017; 3 (1)
View details for DOI 10.1259/bjrcr.20150210
View details for Web of Science ID 000411209500038
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Duodenal invasion by pancreatic adenocarcinoma: MDCT diagnosis of an aggressive imaging phenotype and its clinical implications.
Abdominal radiology (New York)
2017
Abstract
Despite advances in oncologic and imaging technology, pancreatic ductal adenocarcinoma remains a highly deadly disease. The only curative option, pancreaticoduodenectomy or pancreatectomy, carries a significant morbidity. Current imaging plays a role in pre-operative staging to determine the probability of achieve disease-free margins. However, a small but not insignificant number of pancreatic cancers have a relatively higher aggressive biology, despite being resectable based on traditional criteria. Recently, imaging biomarkers that serve as a surrogate for tumors with such aggressive phenotype have been described. These include duodenal invasion and extrapancreatic perineural invasion. This review will focus on the former highlighting the summary of literature supporting duodenal invasion as a surrogate for aggressive disease as well as review its MDCT imaging features.
View details for PubMedID 28770287
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Preoperative Multidetector CT Diagnosis of Extrapancreatic Perineural or Duodenal Invasion Is Associated with Reduced Postoperative Survival after Pancreaticoduodenectomy for Pancreatic Adenocarcinoma: Preliminary Experience and Implications for Patient Care
RADIOLOGY
2016; 281 (3): 816-825
Abstract
Purpose To test the hypothesis that patients with pancreatic adenocarcinoma who otherwise are viewed to have resectable disease but have preoperative findings of extrapancreatic perineural invasion (EPNI) and/or duodenal invasion at multidetector computed tomography (CT) have reduced postoperative survival after pancreaticoduodenectomy for pancreatic ductal adenocarcinoma (PDAC). Materials and Methods This study was approved by the institutional review board and complied with HIPAA. The authors retrospectively evaluated 76 consecutive patients with PDAC who underwent preoperative multidetector CT and subsequent pancreaticoduodenectomy. Two radiologists blinded to surgical pathology results and clinical outcome evaluated multidetector CT images for evidence of EPNI and duodenal invasion; discrepancies were resolved by consensus. Also determined for each patient were resected lymph node status, tumor size, surgical margin status, time to progression, and time to death. Data were assessed with the Goodman-Kruskal gamma for correlations among indicators and the log-rank test, Kaplan-Meier estimates, and multivariate Cox proportional hazards regression for survival analysis. Results In univariate analysis, duodenal invasion and/or EPNI on preoperativemultidetector CT images was associated with significantly decreased progression-free survival (P < .0001) and overall survival (P = .0013), and the clinical indicators (lymph node status, tumor size, and surgical margin status) as well as duodenal invasion and/or EPNI showed correlation with each other. In multivariate regression that included multidetector CT findings as well as the three traditional clinical indicators, only duodenal invasion and/or EPNI showed significant independent association with reduction in both modes of survival (P < .0001 and P = .014, respectively). Interobserver agreement was substantial with respect to EPNI and duodenal invasion (κ = 0.691 and 0.682, respectively). Conclusion Patients with evidence of EPNI and/or duodenal invasion on preoperative multidetector CT images have significantly reduced survival after pancreaticoduodenectomy for PDAC. (©) RSNA, 2016.
View details for DOI 10.1148/radiol.2016152790
View details for PubMedID 27438167
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Multidetector CT imaging of the pancreatic groove: differentiating carcinomas from paraduodenal pancreatitis
CLINICAL IMAGING
2016; 40 (6): 1246-1252
Abstract
This study aims to identify multidetector row CT (MDCT) findings that differentiate paraduodenal pancreatitis (PDP) from groove carcinomas (GC).Two radiologists retrospectively reviewed various imaging features on pancreas protocol CT scans of 8 PDP and 8 GC patients. Two-tailed Fisher's Exact Test was used for statistical analysis.MDCT findings correlating with PDP included benign common bile duct morphology (P<.01), duodenal wall thickening (P<.05), and cystic groove lesions (P<.01). A statistical difference in gastroduodenal artery (GDA) encasement was not observed (P=.119).There are several MDCT findings that favor PDP over GC. However, presence of GDA encasement is not a reliable distinguishing feature.
View details for DOI 10.1016/j.clinimag.2016.08.004
View details for Web of Science ID 000387529900029
View details for PubMedID 27636383
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Color Doppler Imaging of the Appendix: Criteria to Improve Specificity for Appendicitis in the Borderline-Size Appendix.
Journal of ultrasound in medicine
2016; 35 (10): 2129-2138
Abstract
To test the hypothesis that continuous intramural vascular signal measuring at least 3 mm on color Doppler imaging is highly specific for appendicitis in patients with diagnostically borderline-size appendices.Two blinded observers independently reviewed color Doppler images of the appendix in 94 consecutive patients who had undergone sonography for suspected appendicitis and whose appendices were of diagnostically borderline size (6-8 mm maximum outer diameter). Intramural vascular flow on color Doppler images was classified as absent, type 1 (only punctate and dispersed signal), or type 2 (continuous linear or curvilinear signal measuring at least 3.0 mm in long- or short-axis views). Histopathologic examination and clinical follow-up served as reference standards. Proportions were assessed by the exact binomial test.Of the 94 patients, 33 (35.1%) had type 1 flow (of whom 5 [15.2%] had appendicitis); 23 (24.5%) had type 2 flow (of whom 20 [87.0%] had appendicitis); and 38 (40.4%) had absent flow (of whom 10 [26.3%] had appendicitis). The sensitivity, specificity, and odds ratio of type 2 flow as an indicator of appendicitis were 57.1%, 94.9%, and 24.9 (P< .001), respectively; the corresponding values for type 1 flow as an indicator of normal appendices were and 47.5%, 85.7%, and 5.4 (P = .002).Continuous intramural linear or curvilinear signal measuring at least 3 mm on color Doppler imaging is a highly specific, although relatively insensitive, sign of acute appendicitis in noncompressible appendices of diagnostically borderline size (6-8 mm).
View details for DOI 10.7863/ultra.15.11064
View details for PubMedID 27562977
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Lymphoid Hyperplasia of the Appendix: A Potential Pitfall in the Sonographic Diagnosis of Appendicitis
AMERICAN JOURNAL OF ROENTGENOLOGY
2016; 206 (1): 189-194
Abstract
The objective of this study was to test the hypothesis that thickening of the lamina propria, a finding produced by lymphoid hyperplasia, is significantly associated with false-positive sonographic diagnoses of appendicitis in 6- to 8-mm noncompressible appendixes.Sonograms of 119 consecutive patients with suspected appendicitis and 6- to 8-mm noncompressible appendixes were retrospectively blindly evaluated for thickening of the lamina propria (short axis thickness ≥ 1 mm). The reference standard for appendicitis was pathologic analysis of resected specimens. Results were compared with the two-tailed Fisher exact test.Thirty-one patients (26.1%) had a thickened lamina propria and 88 (73.9%) did not. Of the 27 pediatric patients with a thickened lamina propria, five (18.5%) had true-positive and 22 (81.5%) had false-positive sonograms for appendicitis; among the 55 pediatric patients without a thickened lamina propria, 27 (49.1%) had true-positive and 28 (50.9%) had false-positive sonograms for appendicitis (p = 0.009). Similar differences in adult patients were not statistically significant. All five pediatric patients with appendicitis and thickened lamina propria also showed two or more findings of periappendiceal fluid, hyperechoic periappendiceal fat, or mural hyperemia on color Doppler examination, compared with two of 22 similar pediatric patients without appendicitis (p < 0.001).Lymphoid hyperplasia may result in a noncompressible appendix 6-8 mm in diameter and may be misdiagnosed as appendicitis in pediatric patients. True-positive diagnoses of appendicitis can be accurately identified by the presence of at least two additional findings from the group of periappendiceal fluid, hyperechoic periappendiceal fat, and mural hyperemia. Identifying the characteristic sonographic appearance of lymphoid hyperplasia may help prevent false-positive misdiagnoses of appendicitis.
View details for DOI 10.2214/AJR.15.14846
View details for Web of Science ID 000367181400038
View details for PubMedID 26700351
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Capsule Ultrasound Device: Further Developments
IEEE. 2016
View details for Web of Science ID 000387497400478
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MDCT Diagnosis of Perineural Invasion Involving the Celiac Plexus in Intrahepatic Cholangiocarcinoma: Preliminary Observations and Clinical Implications.
AJR. American journal of roentgenology
2015; 205 (6): W578-84
View details for DOI 10.2214/AJR.15.14607
View details for PubMedID 26587947
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MDCT Diagnosis of Perineural Invasion Involving the Celiac Plexus in Intrahepatic Cholangiocarcinoma: Preliminary Observations and Clinical Implications.
AJR. American journal of roentgenology
2015; 205 (6): W578-84
Abstract
The purpose of this study was to test the hypothesis that soft-tissue infiltration along the celiac plexus and delayed enhancement exceeding two-thirds of the tumor area on preoperative MDCT correlate with histologic evidence of perineural invasion in resected intrahepatic cholangiocarcinomas.Two experienced abdominal radiologists retrospectively reviewed preoperative multiphasic MDCT scans of 20 patients who underwent resection of intrahepatic cholangiocarcinoma, identifying soft-tissue infiltration along the celiac plexus, delayed enhancement exceeding two-thirds of the tumor area, and maximum tumor diameter. Consensus findings were compared with intratumoral perineural invasion in resected intrahepatic cholangiocarcinomas using the Fisher exact test.Six patients had histologic intratumoral perineural invasion, five of whom had soft-tissue infiltration along the celiac plexus on preoperative MDCT, with corresponding 83.3% sensitivity and 92.9% specificity for perineural invasion and significant association between these MDCT and histologic findings (p = 0.002). No patients with histologic perineural invasion had enhancement exceeding two-thirds of the tumor area on MDCT; sensitivity was 0.0% for this finding. Tumor diameter on MDCT was not significantly associated with perineural invasion at histopathology (p = 0.530).Soft-tissue infiltration along the celiac plexus on MDCT is an indicator of perineural invasion in patients with intrahepatic cholangiocarcinoma. The data did not confirm an association between delayed enhancement exceeding two-thirds of the tumor area and perineural invasion. Because perineural invasion from intrahepatic cholangiocarcinoma is associated with a very poor prognosis and is generally a contraindication to surgery, the MDCT diagnosis of celiac plexus perineural invasion in patients with intrahepatic cholangiocarcinoma may have important implications for prognosis and treatment planning.
View details for DOI 10.2214/AJR.15.14607
View details for PubMedID 26587947
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Predictors of appendicitis on computed tomography among cases with borderline appendix size.
Emergency radiology
2015; 22 (4): 385-394
Abstract
Confident diagnosis of appendicitis when the appendix is borderline (6 to 7 mm) in size can be challenging. This retrospective study assessed computed tomography (CT) findings that are most predictive of appendicitis when the appendix is borderline in diameter. Three radiologists conducted separate, blind retrospective reviews of 105 contrast-enhanced CTs with borderline appendices. Presence or absence of appendicitis was confirmed by chart review of clinical or surgical outcomes. Logistic regression was used to determine the odds ratio (OR) and the receiver operating characteristic for CT features predictive of appendicitis. Absence of intraluminal air (OR = 5.11, p < 0.001), wall hyperemia (OR = 3.92, p = 0.002), wall thickening (OR = 29.7, p < 0.001), and fat stranding (OR = 3.85, p = 0.003) were significant findings in univariate logistic regression. Using a multivariate model, we found that the absence of intraluminal air (OR = 6.04, p = 0.002) and wall thickening (OR = 24.6, p < 0.001) remained statistically significant and were unaffected by adjustment for gender and pediatric age. The area under the curve was significantly greater for the multivariate model than the initial, clinical CT impressions (p = 0.024). The combination of wall thickening and absence of intraluminal air was 92.6 % (95 % CI 75.7-99.1) sensitive and 82.4 % (95 % CI 65.5-93.2) specific for appendicitis. Wall thickening and the absence of intraluminal air are prominent predictors of appendicitis and, if present together, these features may aid in identifying appendicitis on CT when the appendix is borderline in size.
View details for DOI 10.1007/s10140-015-1297-6
View details for PubMedID 25687166
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JOURNAL CLUB: The Alvarado Score as a Method for Reducing the Number of CT Studies When Appendiceal Ultrasound Fails to Visualize the Appendix in Adults.
AJR. American journal of roentgenology
2015; 204 (3): 519-526
Abstract
OBJECTIVE. The purpose of this article is to evaluate the hypothesis that Alvarado scores of 3 or lower identify adult patients who are unlikely to benefit from CT after appendiceal ultrasound fails to show the appendix and is otherwise normal. MATERIALS AND METHODS. We identified 119 consecutive adults for whom the appendix was not seen on otherwise normal appendiceal sonography performed as the first imaging study for suspected appendicitis, who subsequently underwent CT within 48 hours, and whose data permitted retrospective calculation of admission Alvarado scores. Specific benefits of CT were defined as diagnoses of appendicitis or significant alternative findings, and specific benefits were compared between patients with Alvarado scores of 3 or less and 4 or higher. Significant alternative findings on CT were findings other than appendicitis that were treated with medical or surgical therapy during the admission or that were to be addressed during follow-up care. Diagnostic reference standards were discharge diagnoses, pathologic examinations, and clinical follow-up. RESULTS. No patients (0.0%, 0/49) with Alvarado scores 3 or lower had appendicitis, compared with 17.1% (12/70) of patients with Alvarado scores 4 or higher (p = 0.001), and CT showed neither appendicitis nor significant alternative findings in 85.7% (42/49) versus 58.6% (41/70) of these patients, respectively (p = 0.002). The rates of perforated appendicitis, as well as significant alternative CT findings, did not differ significantly. CONCLUSION. Adults with Alvarado scores 3 or lower who have nonvisualized appendixes and otherwise normal appendiceal sonography are at very low risk for appendicitis or significant alternative findings and therefore are not likely to benefit from CT.
View details for DOI 10.2214/AJR.14.12864
View details for PubMedID 25714280
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The Alvarado Score as a Method for Reducing the Number of CT Studies When Appendiceal Ultrasound Fails to Visualize the Appendix in Adults
AMERICAN JOURNAL OF ROENTGENOLOGY
2015; 204 (3): 519-526
Abstract
OBJECTIVE. The purpose of this article is to evaluate the hypothesis that Alvarado scores of 3 or lower identify adult patients who are unlikely to benefit from CT after appendiceal ultrasound fails to show the appendix and is otherwise normal. MATERIALS AND METHODS. We identified 119 consecutive adults for whom the appendix was not seen on otherwise normal appendiceal sonography performed as the first imaging study for suspected appendicitis, who subsequently underwent CT within 48 hours, and whose data permitted retrospective calculation of admission Alvarado scores. Specific benefits of CT were defined as diagnoses of appendicitis or significant alternative findings, and specific benefits were compared between patients with Alvarado scores of 3 or less and 4 or higher. Significant alternative findings on CT were findings other than appendicitis that were treated with medical or surgical therapy during the admission or that were to be addressed during follow-up care. Diagnostic reference standards were discharge diagnoses, pathologic examinations, and clinical follow-up. RESULTS. No patients (0.0%, 0/49) with Alvarado scores 3 or lower had appendicitis, compared with 17.1% (12/70) of patients with Alvarado scores 4 or higher (p = 0.001), and CT showed neither appendicitis nor significant alternative findings in 85.7% (42/49) versus 58.6% (41/70) of these patients, respectively (p = 0.002). The rates of perforated appendicitis, as well as significant alternative CT findings, did not differ significantly. CONCLUSION. Adults with Alvarado scores 3 or lower who have nonvisualized appendixes and otherwise normal appendiceal sonography are at very low risk for appendicitis or significant alternative findings and therefore are not likely to benefit from CT.
View details for DOI 10.2214/AJR.14.12864
View details for Web of Science ID 000351598800030
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Capsule Ultrasound Device
IEEE. 2015
View details for DOI 10.1109/ULTSYM.2015.0168
View details for Web of Science ID 000366045700461
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Three-step sequential positioning algorithm during sonographic evaluation for appendicitis increases appendiceal visualization rate and reduces CT use.
AJR. American journal of roentgenology
2014; 203 (5): 1006-1012
Abstract
The purpose of this article is to examine the rates of appendiceal visualization by sonography, imaging-based diagnoses of appendicitis, and CT use after appendiceal sonography, before and after the introduction of a sonographic algorithm involving sequential changes in patient positioning.We used a search engine to retrospectively identify patients who underwent graded-compression sonography for suspected appendicitis during 6-month periods before (period 1; 419 patients) and after (period 2; 486 patients) implementation of a new three-step positional sonographic algorithm. The new algorithm included initial conventional supine scanning and, as long as the appendix remained nonvisualized, left posterior oblique scanning and then "second-look" supine scanning. Abdominal CT within 7 days after sonography was recorded.Between periods 1 and 2, appendiceal visualization on sonography increased from 31.0% to 52.5% (p < 0.001), postsonography CT use decreased from 31.3% to 17.7% (p < 0.001), and the proportion of imaging-based diagnoses of appendicitis made by sonography increased from 63.8% to 85.7% (p = 0.002). The incidence of appendicitis diagnosed by imaging (either sonography or CT) remained similar at 16.5% and 17.3%, respectively (p = 0.790). Sensitivity and overall accuracy were 57.8% (95% CI, 44.8-70.1%) and 93.0% (95% CI, 90.1-95.3%), respectively, in period 1 and 76.5% (95% CI, 65.8-85.2%) and 95.4% (95% CI, 93.1-97.1%), respectively, in period 2. Similar findings were observed for adults and children.Implementation of an ultrasound algorithm with sequential positioning significantly improved the appendiceal visualization rate and the proportion of imaging-based diagnoses of appendicitis made by ultrasound, enabling a concomitant decrease in abdominal CT use in both children and adults.
View details for DOI 10.2214/AJR.13.12334
View details for PubMedID 25341138
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Value of short-interval computed tomography when sonography fails to visualize the appendix and shows otherwise normal findings.
Journal of ultrasound in medicine
2014; 33 (9): 1589-1595
Abstract
The purpose of this study was to evaluate the type and incidence of disorders revealed by short-interval computed tomography (CT) in patients with suspected appendicitis after graded compression sonography fails to reveal the appendix and shows otherwise normal findings.Computed tomographic findings and clinical courses were assessed retrospectively for 318 patients identified consecutively in a searchable database who met inclusion criteria specifying that sonography was the initial imaging examination for suspected appendicitis; sonography revealed nonvisualization of the appendix and otherwise normal results; and abdominopelvic CT was performed within 48 hours after sonography.Of the 318 patients, short-interval CT revealed normal findings in 250 (78.6%). Appendicitis was revealed in 52 (16.4%) others, of whom 7 had perforation and all of whom had pathologic results confirming these CT findings. Important alternative diagnoses other than appendicitis were revealed in 16 (5.0%) others, including 2 (0.6%) who required urgent surgery and 14 (4.4%) who did not. No significant differences were observed between adult patients (>18 years) and pediatric patients.Most short-interval CT scans in this clinical setting reveal normal findings, and relatively few disclose appendicitis or disorders that require urgent surgery. In view of concerns regarding radiation exposure associated with CT, these observations argue for the development of clinical triage methods that differentiate patients who are likely to benefit from short-interval postsonography CT from those who are not.
View details for DOI 10.7863/ultra.33.9.1589
View details for PubMedID 25154940
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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
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
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The sonographic "bright band sign" of splenic infarction.
Journal of ultrasound in medicine
2014; 33 (6): 929-938
Abstract
To evaluate the frequency of the "bright band sign" in patients with splenic infarcts as well as control patients and to thereby assess whether the bright band sign has potential utility as a sonographic sign of splenic infarction.Using an electronic search engine and image review, 37 patients were retrospectively identified with noncystic parenchymal splenic infarcts on sonography. Nineteen abnormal control patients with noninfarcted splenic lesions on sonography and 100 normal control patients with sonographically normal spleens were also identified. The sonographic appearance of each splenic lesion was evaluated by 2 reviewers and assessed for the bright band sign, defined as thin specular reflectors perpendicular to the sound beam within hypoechoic parenchymal lesions, and for the presence or absence of the classic sonographic appearance of splenic infarction. Possible histologic counterparts of the bright band sign were assessed in archival infarct specimens.The bright band sign was present in 34 (91.9%; 95% confidence interval [CI], 78.1%-98.3%) of 37 patients with splenic infarcts on sonography, including 12 (85.7%; 95% CI, 57.2%-98.2%) of 14 with classic and 22 (95.7%; 95% CI, 78.1%-99.9%) of 23 with nonclassic infarct appearances. No normal or abnormal control patients had the bright band sign. Histologic sections suggested that preserved splenic trabeculae within infarcts may generate the bright band sign.The bright band sign is a potentially useful sonographic sign of splenic infarction, which may confer additional sensitivity and specificity and may be particularly helpful with infarcts having nonclassic appearances.
View details for DOI 10.7863/ultra.33.6.929
View details for PubMedID 24866600
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Sonography of the normal appendix: its varied appearance and techniques to improve its visualization.
Ultrasound quarterly
2013; 29 (4): 333-341
Abstract
The sonographic identification of the normal appendix is crucial to the success of ultrasound as an effective screening method for diagnosing acute appendicitis. The normal appendix can be challenging to identify on sonography, however, because it is a narrow tubular structure and has variable sonographic appearances. Moreover, the tip of the appendix can be quite variable in location. In this article, we review the various sonographic appearances of the normal appendix and highlight strategies to improve its visualization.
View details for DOI 10.1097/RUQ.0b013e3182a2aa8e
View details for PubMedID 24263759
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Sonographic Evaluation of Cervical Lymph Nodes in Papillary Thyroid Cancer
ULTRASOUND QUARTERLY
2013; 29 (1): 25-32
Abstract
Sonography is the modality of choice for imaging cervical lymph nodes in patients with papillary thyroid cancer, both before surgery and for postoperative surveillance. Sonography is also an invaluable tool to guide fine-needle aspiration of abnormal nodes. Microcalcifications, cystic changes, abnormal morphology, and disordered vascularity are features of metastatic nodal involvement with papillary thyroid carcinoma and should be sought during surveillance scans as well as in targeting for fine-needle aspiration.
View details for DOI 10.1097/RUQ.0b013e31827c7a9e
View details for PubMedID 23358214
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Three-dimensional volume-rendered multidetector CT imaging of the posterior inferior pancreaticoduodenal artery: its anatomy and role in diagnosing extrapancreatic perineural invasion.
Cancer imaging
2013; 13 (4): 580-590
Abstract
Extrapancreatic perineural spread in pancreatic adenocarcinoma contributes to poor outcomes, as it is known to be a major contributor to positive surgical margins and disease recurrence. However, current staging classifications have not yet taken extrapancreatic perineural spread into account. Four pathways of extrapancreatic perineural spread have been described that conveniently follow small defined arterial pathways. Small field of view three-dimensional (3D) volume-rendered multidetector computed tomography (MDCT) images allow visualization of small peripancreatic vessels and thus perineural invasion that may be associated with them. One such vessel, the posterior inferior pancreaticoduodenal artery (PIPDA), serves as a surrogate for extrapancreatic perineural spread by pancreatic adenocarcinoma arising in the uncinate process. This pictorial review presents the normal and variant anatomy of the PIPDA with 3D volume-rendered MDCT imaging, and emphasizes its role as a vascular landmark for the diagnosis of extrapancreatic perineural invasion from uncinate adenocarcinomas. Familiarity with the anatomy of PIPDA will allow accurate detection of extrapancreatic perineural spread by pancreatic adenocarcinoma involving the uncinate process, and may potentially have important staging implications as neoadjuvant therapy improves.
View details for DOI 10.1102/1470-7330.2013.0051
View details for PubMedID 24434918
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Three-dimensional volume-rendered multidetector CT imaging of the posterior inferior pancreaticoduodenal artery: its anatomy and role in diagnosing extrapancreatic perineural invasion
CANCER IMAGING
2013; 13 (4): 580-590
View details for DOI 10.1102/1470-7330.2013.0051
View details for Web of Science ID 000209544100014
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Sonography for appendicitis: Nonvisualization of the appendix is an indication for active clinical observation rather than direct referral for computed tomography
JOURNAL OF CLINICAL ULTRASOUND
2012; 40 (8): 455-461
Abstract
To determine the prevalence of perforated and nonperforated appendicitis in patients with nonvisualization of the appendix on ultrasound (US) performed for suspected appendicitis, and to evaluate the value of CT in these patients.We analyzed 400 consecutive patients undergoing US for suspected appendicitis. Of these patients, 260 had nonvisualization of the appendix, but otherwise normal scans. We analyzed the clinical outcome in these patients to determine the prevalence of appendicitis, referrals for CT, and the contribution of CT in these patients.Of the 400 patients, 140 (35%) had either a normal (80 patients, 25%) or an abnormal appendix (60 patients, 15%); 260 (65%) had nonvisualization of the appendix. Overall 75 patients had appendicitis (18.8%) and 17 (4.3%) had appendicitis with perforation. Of the 260 patients with nonvisualization of the appendix, 14 patients (5.4%) had appendicitis and 2 were perforated (0.8%). The prevalence of perforated and nonperforated appendicitis in this group was significantly lower than the overall group (p < 0.001 and p < 0.01, respectively). Of these 260 patients, 101 patients (38.8%) had CT within 48 hours and 79 (78.2%) had normal scans.Patients with nonvisualization of the appendix on US, but otherwise normal scans, are at significantly lower risk for appendicitis, either perforated or nonperforated. Active clinical observation should be considered in these patients, rather than direct referral for CT.
View details for DOI 10.1002/jcu.21928
View details for Web of Science ID 000308645400001
View details for PubMedID 22638942
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MR Enterography in Crohn Disease With Endoscopic Correlation: Protocol, Pearls, and Pitfalls
Annual Meeting of the American-Roentgen-Ray-Society
AMER ROENTGEN RAY SOC. 2012
View details for Web of Science ID 000303667400400
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Split-bolus MDCT urography with synchronous nephrographic and excretory phase enhancement
AMERICAN JOURNAL OF ROENTGENOLOGY
2007; 189 (2): 314-322
Abstract
Our purpose was to evaluate the utility of CT urography performed using a split contrast bolus that yields synchronous nephrographic and excretory phase enhancement.Five hundred consecutive patients referred for evaluation of possible urinary tract abnormalities (327 for painless hematuria) underwent CT urography with unenhanced scanning of the abdomen and pelvis and scanning during concurrent nephrographic and excretory phase enhancement produced by administration of a split contrast bolus. The enhanced abdomen scan was obtained with abdominal compression; the enhanced pelvis scan was obtained after release of compression. Findings from axial sections and coronal maximum intensity projections were correlated with clinical follow-up and, as available, with laboratory and other imaging studies including cystoscopy, ureteroscopy, urine cytology, surgery, and pathology. Follow-up management for each patient was determined by the clinical judgment of the referring physician.CT urography identified 100% of pathologically confirmed renal cell carcinomas (n = 10) and uroepithelial malignancies involving the renal collecting system or ureter (n = 8). An additional nine renal masses were identified for which no pathologic proof has yet been obtained, including eight subcentimeter solid renal masses and one multiloculated lesion. Fourteen of 19 confirmed cases of uroepithelial neoplasm involving the bladder were identified. CT urography yielded one false-positive for bladder tumor, two false-positives for ureteral tumor, and one patient with a bladder mass who refused further evaluation. CT urography yielded sensitivity and specificity of 100% and 99% and 74% and 99% and positive predictive value and negative predictive value of 80% and 100% and 93% and 99% for the renal collecting system and ureter and bladder, respectively. CT urography was ineffective in identifying 11 cases of noninfectious cystitis. CT urography also depicted numerous other congenital and acquired abnormalities of the urinary tract.Split-bolus MDCT urography detected all proven cases of tumors of the upper urinary tract, yielding high sensitivity and specificity. The split-bolus technique has the potential to reduce both radiation dose and the number of images generated by MDCT urography.
View details for DOI 10.2214/AJR.07.2288
View details for Web of Science ID 000248624400012
View details for PubMedID 17646456
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Evaluation of lung nodule growth measurement for MDCT exams with different dosages using synthetic nodules
SPIE-INT SOC OPTICAL ENGINEERING. 2007
View details for DOI 10.1117/12.709774
View details for Web of Science ID 000247298700113
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CT colonography: Influence of 3D viewing and polyp candidate features on interpretation with computer-aided detection
RADIOLOGY
2006; 239 (3): 768-776
Abstract
To retrospectively determine if three-dimensional (3D) viewing improves radiologists' accuracy in classifying true-positive (TP) and false-positive (FP) polyp candidates identified with computer-aided detection (CAD) and to determine candidate polyp features that are associated with classification accuracy, with known polyps serving as the reference standard.Institutional review board approval and informed consent were obtained; this study was HIPAA compliant. Forty-seven computed tomographic (CT) colonography data sets were obtained in 26 men and 10 women (age range, 42-76 years). Four radiologists classified 705 polyp candidates (53 TP candidates, 652 FP candidates) identified with CAD; initially, only two-dimensional images were used, but these were later supplemented with 3D rendering. Another radiologist unblinded to colonoscopy findings characterized the features of each candidate, assessed colon distention and preparation, and defined the true nature of FP candidates. Receiver operating characteristic curves were used to compare readers' performance, and repeated-measures analysis of variance was used to test features that affect interpretation.Use of 3D viewing improved classification accuracy for three readers and increased the area under the receiver operating characteristic curve to 0.96-0.97 (P<.001). For TP candidates, maximum polyp width (P=.038), polyp height (P=.019), and preparation (P=.004) significantly affected accuracy. For FP candidates, colonic segment (P=.007), attenuation (P<.001), surface smoothness (P<.001), distention (P=.034), preparation (P<.001), and true nature of candidate lesions (P<.001) significantly affected accuracy.Use of 3D viewing increases reader accuracy in the classification of polyp candidates identified with CAD. Polyp size and examination quality are significantly associated with accuracy.
View details for Web of Science ID 000237738600018
View details for PubMedID 16714460
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Measurement of renal extraction fraction with contrast-enhanced CT
RADIOLOGY
2005; 236 (3): 1029-1033
Abstract
Study was approved by the institutional review board, and informed patient consent was waived. A method for minimization of sources of variability in measuring single-kidney extraction fraction (EF) was determined retrospectively with contrast material-enhanced computed tomography (CT). Ten adults underwent CT of the kidneys; precontrast scans were obtained, followed by postcontrast scanning 2 minutes after contrast material injection. Single-kidney EF was then calculated for each patient with the formula EF = (CT(A) - CT(V))/(CT(A) - CT(PRE)), where CT(A) and CT(V) are the postcontrast CT values (in Hounsfield units) of the systemic blood and renal venous blood, respectively, and CT(PRE) is the precontrast CT value of the blood. Both conventional two-dimensional and volumetric three-dimensional regions of interest were used for determining mean CT values of the blood. By using the volumetric regions of interest, left and right renal EF values averaged 17.3% and 18.0%, respectively, for two observers, compared with the accepted value of 15%-20%. This latter technique also minimized right-left kidney and interobserver variability in the measurement of EF.
View details for DOI 10.1148/radiol.2363041371
View details for Web of Science ID 000231412600039
View details for PubMedID 16020561
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Computed tomography colonography - Feasibility of computer-aided polyp detection in a "First reader" paradigm
88th Scientific Assembly and Annual Meeting of the Radiological-Society-of-North-America
LIPPINCOTT WILLIAMS & WILKINS. 2004: 318–26
Abstract
: To determine the feasibility of a computer-aided detection (CAD) algorithm as the "first reader" in computed tomography colonography (CTC).: In phase 1 of a 2-part blind trial, we measured the performance of 3 radiologists reading 41 CTC studies without CAD. In phase 2, readers interpreted the same cases using a CAD list of 30 potential polyps.: Unassisted readers detected, on average, 63% of polyps > or =10 mm in diameter. Using CAD, the sensitivity was 74% (not statistically different). Per-patient analysis showed a trend toward increased sensitivity for polyps > or =10 mm in diameter, from 73% to 90% with CAD (not significant) without decreasing specificity. Computer-aided detection significantly decreased interobserver variability (P = 0.017). Average time to detection of the first polyp decreased significantly with CAD, whereas total reading case reading time was unchanged.: Computer-aided detection as a first reader in CTC was associated with similar per-polyp and per-patient detection sensitivity to unassisted reading. Computer-aided detection decreased interobserver variability and reduced the time required to detect the first polyp.
View details for Web of Science ID 000221234500003
View details for PubMedID 15100534
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Guidelines regarding HIV and other bloodborne pathogens in vascular/interventional radiology.
Journal of vascular and interventional radiology
2003; 14 (9): S375-84
View details for PubMedID 14514850
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Rapid measurement of time-averaged blood flow using ungated spiral phase-contrast
MAGNETIC RESONANCE IN MEDICINE
2003; 49 (2): 322-328
Abstract
A novel ungated spiral phase-contrast (USPC) imaging method was developed for rapid measurement of time-averaged blood-flow rates in the presence of pulsatility. The spatial point-spread function was analyzed to provide an intuitive understanding of how spiral trajectories, which sample the k-space origin at every excitation, can mitigate the effects of pulsatility. Pulsatile flow phantom experiments were performed to validate the accuracy and repeatability of the USPC method. The measurement of flow in the renal and femoral arteries of normal volunteers were also performed. The phantom results (error < or = +9%, SD(phantom) < or = 2%, time-averaged pulsatile-flow rates = 3-15 ml/s) and in vivo results (SD(renal) < or = 8%, SD(femoral) < or = 14%) demonstrate the potential of the USPC method for rapidly and repeatedly measuring accurate time-averaged blood flow even in relatively small arteries and in the presence of strong pulsatility.
View details for DOI 10.1002/mrm.10369
View details for Web of Science ID 000180807100016
View details for PubMedID 12541253
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CT colonography: Improved polyp detection sensitivity and efficiency with computer aided detection (CAD)
88th Scientific Assembly and Annual Meeting of the Radiological-Society-of-North-America
RADIOLOGICAL SOC NORTH AMERICA. 2002: 304–304
View details for Web of Science ID 000178825100757
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Imaging of skeletal muscle function using (18)FDG PET: force production, activation, and metabolism
JOURNAL OF APPLIED PHYSIOLOGY
2001; 90 (1): 329-337
Abstract
The purpose of this study was to determine whether [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET) can be used to evaluate muscle force production, create anatomic images of muscle activity, and resolve the distribution of metabolic activity within exercising skeletal muscle. Seventeen subjects performed either elbow flexion, elbow extension, or ankle plantar flexion after intravenous injection of FDG. PET imaging was performed subsequently, and FDG uptake was measured in skeletal muscle for each task. A fivefold increase in resistance during elbow flexion increased FDG uptake in the biceps brachii by a factor of 4. 9. Differences in relative FDG uptake were demonstrated as exercise tasks and loads were varied, permitting differentiation of active muscles. The intramuscular distribution of FDG within exercising biceps brachii varied along the transverse and longitudinal axes of the muscle; coefficients of variation along these axes were 0.39 and 0.23, respectively. These findings suggest FDG PET is capable of characterizing task-specific muscle activity and measuring intramuscular variations of glucose metabolism within exercising skeletal muscle.
View details for Web of Science ID 000167547600042
View details for PubMedID 11133926
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Focal liver lesions: Pattern-based classification scheme for enhancement at arterial phase CT
RADIOLOGY
2000; 215 (3): 746-751
Abstract
To present our early experience with a classification scheme for categorizing focal liver lesions on the basis of the enhancement patterns that they exhibit in the arterial phase of computed tomography (CT) and to determine whether particular enhancement patterns suggest particular diagnoses.The authors reviewed arterial phase CT images in 100 consecutive patients with focal liver lesions, excluding simple cysts. The enhancement pattern of the dominant or representative lesion in each patient was classified into one of five categories-homogeneous, abnormal internal vessels or variegated, peripheral puddles, complete ring, or incomplete ring-by three radiologists blinded to the proved diagnosis. Lesions without enhancement were recorded separately. Agreement was reached by consensus in all cases. Standards of reference included findings at histologic examination, correlative imaging, or clinical and imaging follow-up.Ninety-two percent of the 100 lesions demonstrated arterial phase enhancement. Patterns associated with positive predictive values of 82% or greater and specificity of 80% or greater included abnormal internal vessels or variegated (hepatocellular carcinoma), peripheral puddles (hemangioma), and complete ring (metastasis).The appearance of hepatic lesions in the arterial phase of enhancement has potential use in the determination of specific diagnoses. The classification scheme used in this study may be a useful tool for the interpretation of arterial phase CT studies.
View details for Web of Science ID 000087247000020
View details for PubMedID 10831693
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Aortic aneurysmal disease: Assessment of stent-graft treatment - CT versus conventional angiography
RADIOLOGY
2000; 215 (1): 138-146
Abstract
To compare computed tomographic (CT) angiography and conventional angiography for determining the success of endoluminal stent-graft treatment of aortic aneurysms.Forty patients underwent conventional angiography and CT angiography following treatment of aortoiliac aneurysms with endoluminal stent-grafts. Six additional sets of conventional angiographic-CT angiographic examinations were performed in five patients after placement of additional stent-grafts or coil embolization to treat perigraft leakage. Three faculty CT radiologists who were blinded to patient clinical data and outcome independently interpreted the CT angiograms, and three faculty angiographers, who were not involved in the stent-graft deployment, interpreted the conventional angiograms. Images were assessed for the presence of postdeployment complications. A reference standard was developed by experienced radiologists using all available images and clinical data. Sensitivities, specificities, and kappa values were calculated.Perigraft leakage was the most commonly identified complication. Twenty perigraft leaks were detected in the results of 46 examinations. Sensitivities and specificities for detecting perigraft leakage were 63% and 77% for conventional angiography and 92% and 90% for CT angiography, respectively. The kappa value was 0. 41 for conventional angiography and 0.81 for CT angiography.CT angiography is the preferred method for establishing the presence of perigraft leakage following treatment of aortoiliac aneurysms with stent-grafts.
View details for Web of Science ID 000086156700021
View details for PubMedID 10751479
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High-resolution three-dimensional in vivo imaging of atherosclerotic plaque
MAGNETIC RESONANCE IN MEDICINE
1999; 42 (4): 762-771
Abstract
The internal structure of atherosclerotic-plaque lesions may be a useful predictor of which lesions will rupture and cause sudden events such as heart attack or stroke. With lipid and flow suppression, we obtained high-resolution, three-dimensional (3D) images of atherosclerotic plaque in vivo that show the cap thickness and core size of the lesions. 3D GRASE was used because it provides flexible T(2) contrast and good resistance to off-resonance artifacts. While 2D RARE has similar properties, its resolution in the slice-select direction, which is important because of the irregular geometry of atherosclerotic lesions, is limited by achievable slice-excitation profiles. Also, 2D imaging generally achieves lower SNR than 3D imaging because, for SNR purposes, 3D image data is averaged over all the slices of a corresponding multislice 2D dataset. Although 3D RARE has many of the advantages of 3D GRASE, it requires a longer scan time because it uses more refocusing pulses to acquire the same amount of data. Finally, cardiac gating is an important part of our imaging sequence, but can make the imaging time quite long. To obtain reasonable scan times, a 2D excitation pulse was used to restrict the field of view. Magn Reson Med 42:762-771, 1999.
View details for Web of Science ID 000082944400019
View details for PubMedID 10502766
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Flow quantification using low-spatial-resolution and low-velocity-resolution velocity images
MAGNETIC RESONANCE IN MEDICINE
1999; 42 (4): 682-690
Abstract
In this report, a flow-quantification method using Fourier velocity encoding (FVE) with limited spatial and velocity resolution is presented. The total flow rate in a vessel corresponds to the first moment of the velocity histogram of spins in the vessel, whereas the spin density of flowing spins is the normalization constant. Because the measured histogram using FVE is distorted by RF saturation effects, the RF saturation effects are first estimated and then accurately compensated by acquiring five velocity-encoded images. The spatial resolution in each image can be relatively low because all stationary spins vanish in the resultant flow map. In a phantom study, the errors in measured flow rates were within +/-10% even when the pixel size was greater than the vessel size. This method was also successfully applied to measure flow in the femoral artery. In general, this method constitutes a basis for analyzing multiple velocity-encoded images and is particularly useful for quantifying slow flow or flow in small vessels. Magn Reson Med 42:682-690, 1999.
View details for Web of Science ID 000082944400009
View details for PubMedID 10502756
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Magnetic resonance imaging of postpartum pelvic hematomas: Early experience in diagnosis and treatment planning
MAGNETIC RESONANCE IMAGING
1999; 17 (7): 973-977
Abstract
The purpose of this study was to determine the utility of magnetic resonance imaging (MRI) in detecting and localizing clinically non-apparent postpartum pelvic hematomas, and to describe the therapeutic implications of MRI in these patients. MRI examinations were performed on seven women with pelvic pain and/or fullness following difficult vaginal deliveries. None had clinically evident hematomas, and none were scheduled for surgery. Hematomas in the pelvis were identified with conventional T1-weighted, and conventional and fast spin echo T2-weighted sequences. Intravenous contrast was not used. Pelvic hematomas were identified in contiguity with the vagina, cervix, and bladder, within the broad ligament, and in the presacral space. In two patients, hematomas were confined to the perivaginal and pericervical regions. In three patients, perivaginal hematomas extended between the double layers of the broad ligaments. In one patient, a perivaginal hematoma extended into the perivesical space. In one patient, a hematoma was identified only within the presacral space. Based on MRI as the only contributory imaging study, five patients were treated successfully with invasive means and two patients were managed successfully with conservative means. MRI successfully detects and localizes postpartum hematomas, information that often is unavailable from the clinical examination. This information facilitates decisions regarding the need for intervention and the appropriate type of procedure when intervention is necessary for this potentially life-threatening problem. We advocate the use of MRI to evaluate patients at risk for postpartum hemorrhage following difficult vaginal deliveries.
View details for Web of Science ID 000082020600004
View details for PubMedID 10463646
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Advantages bf performing sonourethrography with lidocaine hydrochloride jelly in a prepackaged delivery system
AMERICAN JOURNAL OF ROENTGENOLOGY
1999; 173 (1): 39-40
View details for Web of Science ID 000081010900009
View details for PubMedID 10397096
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Liver tumors: Utility of characterization at dual-frequency US
RADIOLOGY
1999; 211 (3): 629-636
Abstract
To evaluate the potential utility of a technique for analysis of ultrasonographic (US) images obtained at two center frequencies in a phantom model and in a clinical study of liver tumors.A US phantom was built that contained target regions with polystyrene scatterers both smaller and larger than scatterers in the background material. High- and low-frequency US images of target regions were obtained, and changes in the contrast-to-noise ratio (CNR) of the targets relative to the background were determined. In a clinical evaluation, 12 hemangiomas, 13 liver metastases, one adenoma, and two hepatomas were evaluated in a similar manner, and the results were correlated with the histologic findings in resected lesions.For targets containing scatterers smaller than those in the background, there was an increase in CNR of higher frequency images. The converse was true for target regions having scatterers larger than those in the background. Liver metastases generally showed an increase in CNR of higher frequency images, whereas hemangiomas generally showed somewhat decreased CNR of higher frequency images, differing significantly from metastases (P < .01-.001).Changes in CNRs of relatively high- and low-frequency US images may give useful information on the frequency dependence of backscattering, which is descriptive of the histologic findings in lesions and which is not evident with conventional US images.
View details for Web of Science ID 000080446000007
View details for PubMedID 10352584
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Unenhanced CT in the evaluation of urinary calculi: Application of advanced computer methods
SEMINARS IN ULTRASOUND CT AND MRI
1999; 20 (2): 136-141
Abstract
Recent advances in computer hardware and software technology enable radiologists to examine tissues and structures using three-dimensional figures constructed from the multiple planar images acquired during a spiral CT examination. Three-dimensional CT techniques permit the linear dimensions of renal calculi to be determined along all three coordinate axes with a high degree of accuracy and enable direct volumetric analysis of calculi, yielding information that is not available from any other diagnostic modality. Additionally, three-dimensional techniques can help to identify and localize calculi in patients with suspected urinary colic.
View details for Web of Science ID 000079764600008
View details for PubMedID 10222520
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Ultra-short echo-time 2D time-of-flight MR angiography using a half-pulse excitation
MAGNETIC RESONANCE IN MEDICINE
1999; 41 (3): 591-599
Abstract
Flow-related artifacts remain a significant concern for magnetic resonance (MR) angiography because their appearance in angiograms adversely impacts accuracy in evaluation of arterial stenoses. In this paper, a half-pulse excitation scheme for improved two-dimensional time-of-flight (2D TOF) angiography is described. The proposed method eliminates the need for gradient moment nulling (of all orders), providing significant reductions in spin dephasing and consequent artifactual signal loss. Furthermore, because the post-excitation refocusing and flow compensation gradients are obviated, the achievable echo time is dramatically shortened. The half-pulse excitation is employed in conjunction with a fast radial-line acquisition, allowing ultra-short echo times on the order of 250-300 microsec. Radial-line acquisition methods also provide additional benefits for flow imaging: effective mitigation of pulsatile flow artifacts, full k-space coverage, and decreased scan times. The half-pulse excitation/radial-line sequence demonstrated improved performance in initial clinical evaluations of the carotid bifurcation when compared with a conventional 2D TOF sequence.
View details for Web of Science ID 000079317800023
View details for PubMedID 10204884
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Effects of niacin therapy that simulate neoplasia: Hepatic steatosis with concurrent hepatic dysfunction
JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY
1999; 23 (2): 314-317
Abstract
Niacin, a widely used antihyperlipidemic agent, can produce hepatic steatosis and clinical hepatic abnormalities that together simulate the presentation of hepatobiliary neoplasia. We describe a patient initially suspected of having hepatobiliary neoplasia for whom imaging studies played a pivotal role in reaching the correct diagnosis of niacin-induced hepatotoxicity. Radiologists should become knowledgeable of these niacin-related effects, add niacin effects to the differential diagnosis of hepatic steatosis, and understand the value of correlative imaging in distinguishing these effects from hepatobiliary neoplasia.
View details for Web of Science ID 000079202400025
View details for PubMedID 10096345
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Differentiation of hepatic malignancies from hemangiomas and cysts by T2 relaxation times: Early experience with multiply refocused four-echo imaging at 1.5 T
JOURNAL OF MAGNETIC RESONANCE IMAGING
1999; 9 (1): 81-86
Abstract
The purpose of this study was to examine hepatic lesions with a sequence designed to yield improved T2 measurements and evaluate the clinical utility of these measurements in distinguishing malignant from benign disease. Using a modified Carr-Purcell sequence incorporating features designed to compensate for imperfections in the imaging system, including a train of refocusing pulses emitted in an MLEV pattern oriented in composite fashion along all three coordinate axes, and a single spatially selective pulse placed immediately before a spiral readout, 14 benign lesions and 13 malignant lesions were evaluated prospectively with a conventional 1.5 T imager. The maximum, minimum, and mean T2 values of malignant lesions, hemangiomas, and cysts exceeded corresponding published values from spin-echo and echoplanar studies. The mean T2 value of the malignant lesions differed significantly (P < 0.0001) from those of hemangiomas and cysts. All malignant lesions and all benign lesions were distinguishable by their T2 values, which had ranges of no greater than 118.6 msec and no less than 134.3 msec, respectively. This early experience suggests that improved T2 measurements can facilitate the differentiation of hepatic malignancies from hemangiomas and cysts.
View details for Web of Science ID 000080144300011
View details for PubMedID 10030654
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Urinary bladder pseudolesions on contrast-enhanced helical CT: Frequency and clinical implications
AMERICAN JOURNAL OF ROENTGENOLOGY
1998; 171 (5): 1349-1354
Abstract
The goals of this study were to define the distinguishing characteristics and frequency of urinary bladder pseudolesions that are produced as opacified urine enters the bladder during contrast-enhanced helical CT of the abdomen and to evaluate the usefulness of delayed imaging in differentiating pseudolesions from true lesions.Contrast-enhanced routine CT scans of 184 patients were obtained prospectively. For each patient, we also obtained 5-min delayed images of the bladder. The images were evaluated for apparent focal thickening or polypoid lesions involving the bladder wall, findings that may represent bladder neoplasia, without knowledge of the indications for the scan, the patient's clinical history, or the patient's diagnosis. Apparent lesions that were visible on routine images and entirely absent on delayed images were considered to be pseudolesions.Apparent lesions were identified on 20 (10.9%+/-4.5% [limits of the 95% confidence interval]) of the routine CT scans. Using delayed images, the 21 apparent lesions in these 20 patients were resolved as 13 pseudolesions and eight true lesions. Pseudolesions were present in 6.5%+/-3.6% of patients.Pseudolesions of the bladder that are indistinguishable from true lesions pose a significant clinical problem in routine contrast-enhanced helical CT of the abdomen. Delayed imaging of the bladder is useful in distinguishing pseudolesions from true lesions.
View details for Web of Science ID 000076580400036
View details for PubMedID 9798877
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Dual-phase helical CT of locally invasive pancreatic adenocarcinoma.
Journal of computer assisted tomography
1998; 22 (2): 282-287
Abstract
Dual-phase helical CT permits imaging of the pancreas and the peripancreatic structures in the arterial dominant and portal venous phases of enhancement, providing information crucial in the assessment of the local extent of pancreatic adenocarcinoma. This essay reviews the dual-phase helical CT findings of local extension that preclude potentially curative surgery, including vascular involvement, ligamentous or mesenteric invasion, extension of the tumor to involve the stomach or duodenum, and invasion of adjacent solid organs.
View details for PubMedID 9530395
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Pictorial essay - Dual-phase helical CT of locally invasive pancreatic adenocarcinoma
JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY
1998; 22 (2): 282-287
Abstract
Dual-phase helical CT permits imaging of the pancreas and the peripancreatic structures in the arterial dominant and portal venous phases of enhancement, providing information crucial in the assessment of the local extent of pancreatic adenocarcinoma. This essay reviews the dual-phase helical CT findings of local extension that preclude potentially curative surgery, including vascular involvement, ligamentous or mesenteric invasion, extension of the tumor to involve the stomach or duodenum, and invasion of adjacent solid organs.
View details for Web of Science ID 000072592200022
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Power Doppler imaging in preoperative planning and postoperative monitoring of muscle flaps
JOURNAL OF CLINICAL ULTRASOUND
1997; 25 (9): 465-471
Abstract
We assessed the utility of power Doppler imaging (PDI) in preoperative planning and postoperative evaluation of microvascular tissue transfers.Twenty-five PDI studies were performed on 23 patients using a 5-10-MHz linear-array transducer. Thirteen patients were assessed preoperatively for patency of the desired donor vessel; 8 of them had surgical scars overlying the desired vascular territory. Twelve patients (including 2 from the first group) were evaluated postoperatively for patency of the vascular anastomoses and adequacy of the blood supply to the transferred tissue.Twelve of the 13 patients assessed preoperatively had successful flap transfers. Four of the 8 patients with scars over the desired vascular territories had absent or aberrant arteries, necessitating a change in the operative plan. None of these patients had operative complications. Eight of the 12 patients scanned postoperatively had patent anastomoses. In 2 of these patients, impending surgery was averted when the adequacy of the tissue blood supply was established with PDI. In 4 patients, PDI showed arterial or venous compromise, which was confirmed at surgery.PDI is a useful technique in microsurgical tissue transfer for assessing the patency of desired donor vessels preoperatively and for postoperative evaluation of blood supply.
View details for Web of Science ID A1997YC38100001
View details for PubMedID 9350564
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An unusual acute compression fracture of the thoracolumbar spine
ORTHOPEDICS
1997; 20 (10): 975-977
View details for Web of Science ID A1997YD67200011
View details for PubMedID 9362082
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Three-dimensional flow-independent peripheral angiography
MAGNETIC RESONANCE IN MEDICINE
1997; 38 (3): 343-354
Abstract
A magnetization-prepared sequence, T2-Prep-IR, exploits T1, T2, and chemical shift differences to suppress background tissues relative to arterial blood. The resulting flow-independent angiograms depict vessels with any orientation and flow velocity. No extrinsic contrast agent is required. Muscle is the dominant source of background signal in normal volunteers. However, long-T2 deep venous blood and nonvascular fluids such as edema also contribute background signal in some patients. Three sets of imaging parameters are described to address patient-specific contrast requirements. A rapid, spiral-based, three-dimensional readout is utilized to generate high-resolution angiograms of the lower extremities. Comparisons with x-ray angiography and two-dimensional time-of-flight angiography indicate that this flow-independent technique has unique capabilities to accurately depict stenoses and to visualize slow flow and in-plane vessels.
View details for Web of Science ID A1997XW16200001
View details for PubMedID 9339435
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Accuracy of detection and measurement of renal calculi: In vitro comparison of three-dimensional spiral CT, radiography, and nephrotomography
RADIOLOGY
1997; 204 (1): 19-25
Abstract
To compare accuracy of three-dimensional (3D) spiral computed tomography (CT) performed without administration of contrast material with that of radiography and linear nephrotomography in detection and measurement of renal calculi.Fifty renal calculi within an abdominal phantom were imaged with 3D spiral CT, radiography, and linear nephrotomography. Spiral CT data were analyzed with workstation-based 3D imaging software, with a thresholding procedure based on the maximally attenuating voxel within each calculus during measurement. Measurement accuracy and detection rates were compared according to modality. Conventional and magnification-corrected measurements from radiography and linear nephrotomography were included.Spiral CT depicted calculi and allowed determination of the collective two-dimensional and 3D linear measurements statistically significantly more accurately than the other techniques; the mean linear measurement errors along individual axes did not exceed 3.6%. With 3D spiral CT, calculus volumes were determined with a mean error of -4.8%.3D spiral CT enabled highly accurate determination of the volumes and all three linear dimensions of renal calculi. In addition, 3D spiral CT depicted calculi more sensitively than traditional techniques and provided new information and improved accuracy in the evaluation of nephrolithiasis.
View details for Web of Science ID A1997XF19400008
View details for PubMedID 9205217
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Guidelines regarding HIV and other bloodborne pathogens in vascular/interventional radiology. SCVIR Technology Assessment Committee.
Journal of vascular and interventional radiology
1997; 8 (4): 667-676
View details for PubMedID 9232587
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Guidelines regarding HIV and other bloodborne pathogens in vascular/interventional radiology
JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY
1997; 8 (4): 667-676
View details for Web of Science ID A1997XK42500025
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Still the great mimicker: Abdominal tuberculosis
AMERICAN JOURNAL OF ROENTGENOLOGY
1997; 168 (6): 1455-1460
Abstract
Since the mid 1980s, a resurgence of tuberculosis has occurred. The disease is and will remain a serious public health threat worldwide. The clinical and radiologic features of abdominal tuberculosis may mimic those of many diseases. Radiologists evaluating abdominal images should consider the diagnosis of abdominal tuberculosis in immigrants from areas endemic for tuberculosis, in immunocompromised patients, and in high-risk patients such as the homeless. Imaging features that suggest the correct diagnosis are cecal amputation, ileocecal thickening and inflammation, shortening of the ascending colon, gaping of the ileocecal valve, mesenteric adenopathy, a misty mesentery, diffuse omental infiltration, loculate high-density ascites, an enhancing peritoneum with or without an omental line, nodularity of the surface of the mesenteric leaves, and transperitoneal permeation.
View details for Web of Science ID A1997XA55300013
View details for PubMedID 9168707
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Endoscopic sclerotherapy compared with percutaneous transjugular intrahepatic portosystemic shunt after initial sclerotherapy in patients with acute variceal hemorrhage - A randomized, controlled trial
ANNALS OF INTERNAL MEDICINE
1997; 126 (11): 858-?
Abstract
Hemorrhage from esophageal varices remains a substantial management problem. Endoscopic sclerotherapy was preferred for more than a decade, but fluoroscopically placed intrahepatic portosystemic stents have recently been used with increasing frequency.To compare sclerotherapy with transjugular intrahepatic portosystemic shunt (TIPS) in patients with bleeding from esophageal varices.Randomized, controlled clinical trial.Three teaching hospitals.49 adults hospitalized with acute variceal hemorrhage from November 1991 to December 1995: 25 assigned to sclerotherapy and 24 assigned to TIPS.Patients assigned to repeated sclerotherapy had the procedure weekly. In those assigned to TIPS, an expandable mesh stent was fluoroscopically placed between an intrahepatic portal vein and an adjacent hepatic vein.Pretreatment measures included demographic and laboratory data. Postrandomization data included index hospitalization survival, duration of follow-up, successful obliteration of varices, rebleeding from varices, number of variceal rebleeding events, total days of hospitalization for variceal bleeding, blood transfusion requirements after randomization, prevalence of encephalopathy, and total health care costs.Mean follow-up (+/-SE) was 567 +/- 104 days in the sclerotherapy group and 575 +/- 109 days in the TIPS group. Varices were obliterated more reliably by TIPS than by sclerotherapy (P < 0.001). Patients having TIPS were significantly less likely to rebleed from esophageal varices than patients receiving sclerotherapy (3 of 24 compared with 12 of 25; P = 0.012). No other follow-up measures differed significantly between groups. A trend toward improved survival, which was not statistically significant, was noted in the TIPS group (hazard ratio, 0.53 [95% CI, 0.18 to 1.5]).In obliterating varices and reducing rebleeding events from esophageal varies, TIPS was more effective than sclerotherapy. However, TIPS did not decrease morbidity after randomization or improve health care costs. It seemed to produce better survival, but the increase in survival was not statistically significant.
View details for Web of Science ID A1997XA91100002
View details for PubMedID 9163286
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Volume rendering of CT data: Applications to the genitourinary tract
AMERICAN JOURNAL OF ROENTGENOLOGY
1997; 168 (5): 1223-1226
View details for Web of Science ID A1997WV56800017
View details for PubMedID 9129415
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Do arterial phase helical CT images improve detection or characterization of colorectal liver metastases?
JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY
1997; 21 (3): 391-397
Abstract
Our goal was to determine if arterial phase images from dual phase helical CT improve either the detection or the characterization of hepatic metastases in patients with colorectal carcinoma. Sixty-two patients with known colorectal cancer underwent 65 dual phase helical CT examinations to evaluate for possible liver metastases. Three blinded reviewers independently evaluated the portal venous phase images alone to determine if hepatic metastases were present or absent. Arterial phase images were then analyzed to determine if they identified additional lesions or aided in characterizing small hepatic lesions. Scores of the two methods for diagnosing metastases were compared with the "gold standard" established by a consensus panel of three other radiologists who reviewed all images together with clinical, pathologic, and other imaging data. The addition of arterial phase imaging did not detect any new metastases. However, in 6 of the 64 technically adequate examinations, hepatic arterial phase images increased lesion conspicuity and significantly increased diagnostic confidence when compared with portal vein phase scans alone. In patients with colorectal cancer, the addition of arterial phase imaging does not increase sensitivity, but improves the specificity in diagnosing liver metastases in a small number of cases. Dual phase helical CT does not appear to be indicated in the evaluation of liver metastases from colorectal cancer.
View details for Web of Science ID A1997WV86400010
View details for PubMedID 9135646
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Power versus color Doppler sonography of the normal cystic artery: Implications for patients with acute cholecystitis
AMERICAN JOURNAL OF ROENTGENOLOGY
1997; 168 (3): 703-705
Abstract
The purposes of this investigation were to compare prospectively the pattern and extent of cystic artery flow revealed by power Doppler sonography and color Doppler sonography in patients with normal gallbladders and to analyze the potential implications of these findings for power Doppler sonography in diagnosing acute cholecystitis.The cystic arteries of 142 patients (79 women and 63 men) with normal gallbladders were imaged with both power Doppler sonography and color Doppler sonography using 5-MHz transducers and settings optimized to reveal low-volume flow. The presence or absence of cystic artery flow and the anatomic extent of its visualization were recorded for each patient.Power Doppler sonography revealed flow in 73% of patients with normal gallbladders compared with 53% revealed by color Doppler sonography. Cystic artery flow within the distal fundal quartile was revealed by power Doppler sonography in 20% of patients and flow spanning greater than 50% of the anterior gallbladder wall was revealed by power Doppler sonography in 17% of patients. These findings differed from those of color Doppler sonography at a highly significant level (p < .0001, chi-square test).Power Doppler sonography is significantly more sensitive than color Doppler sonography for revealing cystic artery flow in patients with normal gallbladders. The flow patterns in patients with normal gallbladders obtained with power Doppler sonography overlap flow patterns previously reported as fairly specific criteria for diagnosing acute cholecystitis using color Doppler sonography, namely, flow within the distal fundal quartile and flow spanning greater than 50% of the anterior gallbladder wall. Accordingly, these color Doppler sonography criteria are not applicable to the diagnosis of acute cholecystitis with power Doppler sonography. Different power Doppler sonography criteria are necessary for the diagnosis of acute cholecystitis.
View details for Web of Science ID A1997WJ62800027
View details for PubMedID 9057519
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Improved 2D time-of-flight angiography using a radial-line k-space acquisition
MAGNETIC RESONANCE IN MEDICINE
1997; 37 (2): 285-291
Abstract
For flow imaging applications, radial-line k-space acquisition methods offer advantages over conventional 2DFT methods. Specifically, radial-line acquisition methods mitigate artifacts resulting from pulsatile flow while offering a potential reduction in scan times. In this paper, radial-line and 2DFT acquisitions are compared in a two-dimensional time-of-flight angiography sequence. The twisting radial-line (TwiRL) trajectory, a variant of 2D projection reconstruction, is used to represent the family of radial-line trajectories. In both phantom and in vivo studies, the TwiRL images demonstrate improved vessel depiction including a more uniform signal intensity and better delineation of the vasculature in comparison with images obtained via the 2DFT method.
View details for Web of Science ID A1997WD27200020
View details for PubMedID 9001154
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EXTRALUMINAL, TRANSLUMINAL, AND OBSERVATIONAL TREATMENT FOR VERTEBRAL ARTERY INJURIES
JOURNAL OF TRAUMA-INJURY INFECTION AND CRITICAL CARE
1995; 39 (3): 480-486
Abstract
Injury to the vertebral artery following penetrating trauma is rare and treatment is usually surgical ligation. Recent liberal use of angiography in the evaluation of penetrating neck trauma has identified increasing numbers of patients with this challenging injury. This report describes our recent experience in treating patients with vertebral artery injuries. The purposes of this study were (1) to review the outcome of our patients with vertebral artery injuries, and (2) to develop an approach for managing these patients. Sixteen patients were treated over a 9-year period. Three patients underwent emergent operative exploration for bleeding, three underwent transcatheter embolization alone, and ten were managed conservatively by close clinical observation. No deaths occurred. Ligation was performed for injuries discovered during neck exploration, however, bleeding was sometimes persistent despite proximal control. In our center, where radiological support is readily available, temporary control of bleeding by packing with hemostatic agents allowed subsequent transcatheter embolization of the injured artery. Pseudoaneurysms, arteriovenous fistulae, and extravasations discovered angiographically were usually managed by transcatheter embolization. Patients with vertebral artery narrowings or occlusions were managed by close clinical observation.
View details for Web of Science ID A1995TA45800014
View details for PubMedID 7473912
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CATHETER TRACT HEMORRHAGE DURING PERCUTANEOUS BILIARY INTERVENTION - MANAGEMENT WITH USE OF A RETAINED TRANSHEPATIC GUIDE-WIRE
JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY
1995; 6 (3): 433-438
Abstract
The authors present their experience in managing freely flowing hemorrhage from immature catheter tracts in patients undergoing biliary drainage.Transhepatic guide wires were maintained securely whenever catheters were removed from the liver. Six patients among 71 hemorrhaged profusely when drains were manipulated within 4 days of initial catheterization. Management was attempted with use of the transhepatic guide wires.Maneuvers performed over the retained guide wire controlled bleeding in all six patients. Reintubation constituted definitive therapy in five patients. A biliary-portal venous fistula in the remaining patient was treated with thrombin. The retained guide wire proved necessary in all cases.Hemorrhage from immature catheter tracts can be managed, often definitively, with maneuvers performed over a retained transhepatic guide wire. Accordingly, a secure transhepatic guide wire is essential prior to removal of hepatic catheters and should remain in place until the absence of bleeding is established. These maneuvers may become increasingly important as courses of biliary catheterization become shorter.
View details for Web of Science ID A1995RC62600018
View details for PubMedID 7647446
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MORBIDITY AND MORTALITY FOLLOWING MAJOR PENETRATING LIVER INJURIES
ARCHIVES OF SURGERY
1994; 129 (3): 256-261
Abstract
To establish the mortality and morbidity associated with major penetrating liver injuries and to describe the nature and treatment of complications related to these injuries. We postulated that there had been a trend toward less radical initial surgery, as well as an increased utilization of modern imaging techniques in both diagnosing and treating postoperative complications following penetrating liver trauma.A retrospective survey of medical records and radiology files.A university trauma center in an urban setting.Of the 188 patients admitted to our trauma center with penetrating liver trauma between April 1988 and December 1991, 36 had major liver trauma (grades 3 through 5) and are described in this report.The mortality rate, type of operative treatment, and the nature and treatment of complications for each grade of major liver injury.The mortality rate from major liver injuries was 17%. Surgical techniques employed primarily consisted of the use of hemostatic agents and cautery, simple suturing, direct vessel ligation, and packing. Fifty-two percent of the survivors had major complications related to the liver injury itself, but only two required operative therapy. The remaining patients were successfully treated with interventional radiologic techniques.The morbidity and mortality following major penetrating liver injuries remain significant. The majority of hepatobiliary complications can be successfully managed without further surgery but require the combined efforts of the surgeon and interventional radiologist.
View details for Web of Science ID A1994NA52000005
View details for PubMedID 8129599
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POLYARTERITIS-NODOSA MIMICKING HEPATIC CANDIDIASIS ON POSTCONTRAST CT
JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY
1994; 18 (2): 305-307
Abstract
We report a case in which lesions identical to those typical of hepatic candidal microabscesses were caused by polyarteritis nodosa, the recognition of which was essential to avoid potentially toxic therapy for candidiasis and for prompt initiation of successful therapy for progressing symptomatic arteritis.
View details for Web of Science ID A1994NA97100028
View details for PubMedID 7907349
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FATAL REEXPANSION PULMONARY-EDEMA FOLLOWING PLEURAL CATHETER PLACEMENT
JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY
1994; 5 (1): 176-178
View details for Web of Science ID A1994NC90900021
View details for PubMedID 8136600
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SONOGRAPHICALLY DETECTED TESTICULAR MICROLITHIASIS AND TESTICULAR-CARCINOMA
JOURNAL OF CLINICAL ULTRASOUND
1993; 21 (7): 447-452
Abstract
Testicular microlithiasis is an uncommon abnormality that produces the characteristic sonographic appearance of diffuse, punctate, hyperechoic foci throughout the testicular parenchyma. We have detected this distinctive sonographic pattern in 4 patients during a seven-year period. Three of the patients had proven concurrent testicular carcinoma. We describe our experience and review previous reports of testicular microlithiasis. We conclude that testicular microlithiasis may be associated with testicular neoplasia, and advocate particularly careful evaluation and follow-up of the testes when this abnormality is detected.
View details for Web of Science ID A1993LR28800005
View details for PubMedID 8396596
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PLAIN FILM CLUES TO THE DIAGNOSIS OF SPINAL EPIDURAL NEOPLASM AND INFECTION
NEURORADIOLOGY
1993; 35 (4): 288-292
Abstract
Radiographs of 22 normal patients and 35 patients with proven epidural disease were correlated with CT scans to determine the range of normal and abnormal appearances of the osseous surfaces marginating the spinal canal. A subtle but useful plain film clue to early epidural disease was indistinctness of the posterior vertebral body margin, which in at least one case was the solitary radiographic sign of epidural metastasis. The radiographic distinctness of each of the bony margins of the spinal canal varied predictably with spinal level in normal individuals owing to systematic variations in obliquity. Indistinctness of an osseous spinal canal margin, interpreted with knowledge of the range of normal anatomy at the appropriate level, may provide the earliest plain film clue to the presence of spinal epidural disease.
View details for Web of Science ID A1993KX53800016
View details for PubMedID 8492898
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IMAGING OF BLUNT HEPATIC-TRAUMA
RADIOLOGIC CLINICS OF NORTH AMERICA
1991; 29 (6): 1299-1310
Abstract
This article focuses on the clinical role of high resolution computed tomography (CT) in the initial diagnosis and management of hemodynamically stable patients with blunt hepatic trauma. The increased utilization and diagnostic confidence afforded by CT has dramatically changed the surgical approach and need for laparatomy. The most important development has been the growing realization by many trauma surgeons that nonoperative management is often successful in stable patients who have CT evidence of isolated blunt hepatic trauma.
View details for Web of Science ID A1991GN74000011
View details for PubMedID 1947047
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AIDS RISK AND RISK REDUCTION IN THE RADIOLOGY DEPARTMENT
AMERICAN JOURNAL OF ROENTGENOLOGY
1991; 157 (5): 911-917
Abstract
As the AIDS epidemic progresses, concern about the risk of occupational transmission of the causative organism, human immunodeficiency virus (HIV), is increasing. In this article, we summarize the risk of occupational acquisition of HIV in the health care setting and specify protocol and equipment that can reduce this risk in the radiology department. Accidental needle-stick injury is the most common form of exposure to infected blood, which is the only body fluid implicated to date in the occupational transmission of HIV. Prospective cohort studies demonstrate a 0.3-0.4% risk of infection for each needle-stick event. The most important instruction to health care workers that can reduce this risk is the following: Do not recap needles. Other risk-reduction measures include the adoption of universal precautions against transmission of infectious disease; sharp-instrument precautions; the use of protective garb to prevent skin and mucous membrane contamination when blood or bloody body fluid may splash; the availability of stable, puncture-resistant disposal containers for sharp instruments; the exclusion of breakable glass syringes; and the accessibility of resuscitation equipment in all rooms in order to avoid direct mouth-to-mouth contact. These and other measures discussed here are designed to prevent exposure of skin or mucous membrane to blood. If exposure does occur, the contaminated area should be washed immediately. A multicenter research protocol to evaluate the effectiveness of zidovudine (AZT) therapy in preventing seroconversion after exposure to HIV-contaminated blood recommends AZT therapy after massive exposure (e.g., injection of measurable quantities of blood) and endorses it for serious parenteral exposure (e.g., deep needle sticks).
View details for Web of Science ID A1991GL40600001
View details for PubMedID 1927808
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DETECTION OF ACTIVE INTRAABDOMINAL ARTERIAL HEMORRHAGE - VALUE OF DYNAMIC CONTRAST-ENHANCED CT
AMERICAN JOURNAL OF ROENTGENOLOGY
1991; 156 (4): 725-729
Abstract
Contrast-enhanced dynamic CT was used prospectively to diagnose and locate the site of active arterial intraabdominal hemorrhage in 18 patients. Active arterial extravasation was confirmed by angiography in five patients and by immediate surgery in nine. Two patients not undergoing surgery or angiography required multiple blood transfusions to correct rapidly falling hematocrit due to a coagulopathy. One patient died of hypovolemic shock, and autopsy confirmed a large acute retroperitoneal hematoma. Another patient with a splenic laceration and massive hemoperitoneum on CT had no active bleeding at the time of surgery, which was delayed 1 hr from the time of the CT. All patients were clinically thought to be hemodynamically stable and had systolic blood pressures greater than 110 mm Hg at the time of CT. In seven patients, hypotension developed either during (two patients) or immediately after (five patients) CT scanning, necessitating either immediate surgery or angiographic embolization. Contrast-enhanced dynamic CT is valuable in the diagnosis and localization of active arterial intraabdominal hemorrhage. Identification of the anatomic site of this potentially life-threatening hemorrhage is critical in determining whether immediate laparotomy or angiographic embolization is the preferred method of treatment.
View details for Web of Science ID A1991FC83000010
View details for PubMedID 2003435
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Percutaneous transhepatic portal vein angioplasty and stent placement after liver transplantation: early experience.
Journal of vascular and interventional radiology
1990; 1 (1): 17-22
Abstract
In four patients who underwent liver transplantation, portal vein thrombosis was associated with esophageal varices and significant gastrointestinal bleeding. In a fifth liver transplant patient, portal vein stenosis was suspected when evidence of hepatic ischemia was revealed at liver biopsy. Four patients were treated with percutaneous transhepatic portal vein angioplasty. Percutaneous recanalization was precluded by technical factors in the remaining patient. Early in the series, one patient required surgical excision of what proved to be a thick cuff of fibrous tissue and lymph nodes after angioplasty failed to widen the stenosis significantly. Later, a patient with residual stenosis was treated successfully by means of intravascular stent placement. Of the four patients treated, three eventually died secondary to multiple problems unrelated to the percutaneous procedure. This early experience suggests that transhepatic portal vein interventions are feasible in patients who have received liver transplants and may prove useful at least in the early postprocedure period.
View details for PubMedID 2151969
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Magnetic resonance angiography, angiographic contrast media, and digital angiography.
Current opinion in radiology
1990; 2 (2): 252-258
View details for PubMedID 2202394
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LYMPHOMA PRESENTING AS ALLOGRAFT HEMATOMA IN A RENAL-TRANSPLANT RECIPIENT
JOURNAL OF ULTRASOUND IN MEDICINE
1990; 9 (4): 239-241
View details for Web of Science ID A1990CV89100008
View details for PubMedID 2184248
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THE INJECTION TECHNIQUE FOR REPOSITIONING CENTRAL VENOUS CATHETERS
CARDIOVASCULAR AND INTERVENTIONAL RADIOLOGY
1989; 12 (5): 292-293
Abstract
Malpositioned central venous catheters must be repositioned in order to avoid damage caused by concentrated or irritating infusates. Floppy catheters may be repositioned rapidly with a brisk injection of fluid. The ease of this technique, with its anticipated low risk of infection, makes it an attractive alternative to manipulation using guidewires.
View details for Web of Science ID A1989CF42300013
View details for PubMedID 2514994