I am an interventional radiologist with a particular interest in interventional oncology. I perform a wide range of procedures including ablations of the lung, liver, kidney, bone, and other areas in the body, chemoembolization, embolization, and radioembolization of tumors, biopsies, drainages, and interventions on both the venous and arterial sides. I was the first physician to perform SIR-spheres radioembolization for metastatic tumors to the liver within the VA hospital system, and have been recognized for my teaching of trainees. I am currently the Director of Interventional Radiology and Associate Chief of Radiology at the VA Palo Alto Health Care System. My research focuses on HCC and Lung cancer, including the application of Machine Learning/AI and Radiogenomics to lung cancer identification. I also work on Quality in Medicine as the Chair of the Quality and Performance Improvement Division for the Society of Interventional Radiology where we work to define quality measures, gather data via a national IR registry, and develop practice improvement tools.
- Interventional radiology, interventional oncology, ablation, embolization, chemoembolization, biopsy, percutaneous interventions
- Interventional Radiology and Diagnostic Radiology
Clinical Associate Professor, Radiology
Director of Interventional Radiology and Associate Chief of Radiology, VA Palo Alto Health Care System (VAPAHCS) (2017 - Present)
Chief of Interventional Radiology, VA Palo Alto Health Care System (VAPAHCS) (2011 - 2017)
Boards, Advisory Committees, Professional Organizations
Co-Chair Standardized Reporting Sub-Committee, Society of Interventional Radiology (2016 - Present)
Fellowship: Stanford University Pain Management Fellowship (2010) CA
Internship: California Pacific Medical Center Dept of Medicine (2005) CA
Board Certification: American Board of Radiology, Interventional Radiology and Diagnostic Radiology (2017)
Medical Education: Pritzker School of Medicine University of Chicago Registrar (2004) IL
Residency: University of Illinois at Chicago (2009) IL
[18F]FMISO PET/CT After Transcatheter Arterial Embolization in Imaging Tumors in Patients With Liver Cancer
This clinical trial studies how well 18F-fluoromisonidazole ([18F]FMISO) positron emission tomography (PET)/computed tomography (CT) works after transcatheter arterial embolization in imaging tumors in patients with liver cancer. Transcatheter arterial embolization blocks blood flow to tumor cells by inserting tiny foreign particles into an artery near the tumor. [18F]FMISO is a type of radioimaging agent that binds to large molecules in tumor cells that have a low level of oxygen, and the radiation given off by [18F]FMISO is picked up by a PET scan and this may help researchers learn whether changes occur in the tumors after treatment, which can help decide how well the treatment worked earlier than is currently possible
Stanford is currently not accepting patients for this trial. For more information, please contact Rajesh Shah, 650-723-0728.
HepaSphere/Quadrasphere Microspheres for Delivery of Doxorubicin for the Treatment of Hepatocellular Cancer
The purpose of this study is to evaluate overall survival in patients diagnosed with hepatocellular cancer (HCC) treated with HepaSphere/QuadraSphere Microspheres compared to conventional transarterial chemoembolization with particle PVA.
Stanford is currently not accepting patients for this trial. For more information, please contact Risa Jiron, 650-736-1598.
Prostate Artery Embolization With Embosphere Microspheres Compared to TURP for Benign Prostatic Hyperplasia
The purpose of this study is to evaluate improvement of symptoms from benign prostatic hyperplasia (BPH) as assessed by the International Prostate Symptom Score (IPSS) for prostatic artery embolization (PAE) using Embosphere Microspheres compared to conventional transurethral resection of the prostate (TURP).
Stanford is currently not accepting patients for this trial. For more information, please contact Denise Haas, 650-736-1252.
Machine Learning Radiomics Model for Early Identification of Small-Cell Lung Cancer on Computed Tomography Scans.
JCO clinical cancer informatics
2021; 5: 746-757
PURPOSE: Small-cell lung cancer (SCLC) is the deadliest form of lung cancer, partly because of its short doubling time. Delays in imaging identification and diagnosis of nodules create a risk for stage migration. The purpose of our study was to determine if a machine learning radiomics model can detect SCLC on computed tomography (CT) among all nodules at least 1 cm in size.MATERIALS AND METHODS: Computed tomography scans from a single institution were selected and resampled to 1 * 1 * 1 mm. Studies were divided into SCLC and other scans comprising benign, adenocarcinoma, and squamous cell carcinoma that were segregated into group A (noncontrast scans) and group B (contrast-enhanced scans). Four machine learning classification models, support vector classifier, random forest (RF), XGBoost, and logistic regression, were used to generate radiomic models using 59 quantitative first-order and texture Imaging Biomarker Standardization Initiative compliant PyRadiomics features, which were found to be robust between two segmenters with minimum Redundancy Maximum Relevance feature selection within each leave-one-out-cross-validation to avoid overfitting. The performance was evaluated using a receiver operating characteristic curve. A final model was created using the RF classifier and aggregate minimum Redundancy Maximum Relevance to determine feature importance.RESULTS: A total of 103 studies were included in the analysis. The area under the receiver operating characteristic curve for RF, support vector classifier, XGBoost, and logistic regression was 0.81, 0.77, 0.84, and 0.84 in group A, and 0.88, 0.87, 0.85, and 0.81 in group B, respectively. Nine radiomic features in group A and 14 radiomic features in group B were predictive of SCLC. Six radiomic features overlapped between groups A and B.CONCLUSION: A machine learning radiomics model may help differentiate SCLC from other lung lesions.
View details for DOI 10.1200/CCI.21.00021
View details for PubMedID 34264747
Automated coronary calcium scoring using deep learning with multicenter external validation.
NPJ digital medicine
2021; 4 (1): 88
Coronary artery disease (CAD), the most common manifestation of cardiovascular disease, remains the most common cause of mortality in the United States. Risk assessment is key for primary prevention of coronary events and coronary artery calcium (CAC) scoring using computed tomography (CT) is one such non-invasive tool. Despite the proven clinical value of CAC, the current clinical practice implementation for CAC has limitations such as the lack of insurance coverage for the test, need for capital-intensive CT machines, specialized imaging protocols, and accredited 3D imaging labs for analysis (including personnel and software). Perhaps the greatest gap is the millions of patients who undergo routine chest CT exams and demonstrate coronary artery calcification, but their presence is not often reported or quantitation is not feasible. We present two deep learning models that automate CAC scoring demonstrating advantages in automated scoring for both dedicated gated coronary CT exams and routine non-gated chest CTs performed for other reasons to allow opportunistic screening. First, we trained a gated coronary CT model for CAC scoring that showed near perfect agreement (mean difference in scores=-2.86; Cohen's Kappa=0.89, P<0.0001) with current conventional manual scoring on a retrospective dataset of 79 patients and was found to perform the task faster (average time for automated CAC scoring using a graphics processing unit (GPU) was 3.5±2.1s vs. 261s for manual scoring) in a prospective trial of 55 patients with little difference in scores compared to three technologists (mean difference in scores=3.24, 5.12, and 5.48, respectively). Then using CAC scores from paired gated coronary CT as a reference standard, we trained a deep learning model on our internal data and a cohort from the Multi-Ethnic Study of Atherosclerosis (MESA) study (total training n=341, Stanford test n=42, MESA test n=46) to perform CAC scoring on routine non-gated chest CT exams with validation on external datasets (total n=303) obtained from four geographically disparate health systems. On identifying patients with any CAC (i.e., CAC≥1), sensitivity and PPV was high across all datasets (ranges: 80-100% and 87-100%, respectively). For CAC≥100 on routine non-gated chest CTs, which is the latest recommended threshold to initiate statin therapy, our model showed sensitivities of 71-94% and positive predictive values in the range of 88-100% across all the sites. Adoption of this model could allow more patients to be screened with CAC scoring, potentially allowing opportunistic early preventive interventions.
View details for DOI 10.1038/s41746-021-00460-1
View details for PubMedID 34075194
Current Interventional Radiology-Related Benchmarked Clinical Quality Measures Are Less Likely to be "Capped" Than Diagnostic Radiology Clinical Quality Measures.
Journal of vascular and interventional radiology : JVIR
2021; 32 (5): 677–82
In the merit-based incentive payment system (MIPS), quality measures are considered topped out if national median performance rates are ≥95%. Quality measures worth 10 points can be capped at 7 points if topped out for ≥2 years. This report compares the availability of diagnostic radiology (DR)-related and interventional radiology (IR)-related measures worth 10 points. A total of 196 MIPS clinical quality measures were reviewed on the Center for Medicare and Medicaid Services MIPS website. There are significantly more IR-related measures worth 10 points than DR measures (2/9 DR measures vs 9/12 IR measures; P= .03), demonstrating that clinical IR services can help mixed IR/DR groups maximize their Center for Medicare and Medicaid Services payment adjustment.
View details for DOI 10.1016/j.jvir.2020.11.016
View details for PubMedID 33933250
Extravasation Volume at Computed Tomography Angiography Correlates With Bleeding Rate and Prognosis in Patients With Overt Gastrointestinal Bleeding.
Despite the identification of active extravasation on computed tomography angiography (CTA) in patients with overt gastrointestinal bleeding (GIB), a large proportion do not have active bleeding or require hemostatic therapy at endoscopy, catheter angiography, or surgery. The objective of our proof-of-concept study was to improve triage of patients with GIB by correlating extravasation volume of first-pass CTA with bleeding rate and clinical outcomes.All patients who presented with overt GIB and active extravasation on CTA from January 2014 to July 2019 were reviewed in this retrospective, institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study. Extravasation volume was assessed using 3-dimensional software and correlated with hemostatic therapy (primary endpoint) and with intraprocedural bleeding, blood transfusions, and mortality as secondary endpoints using logistic regression models (P < 0.0125 indicating statistical significance). Odds ratios were used to determine the effect size of a threshold extravasation volume. Quantitative data (extravasation volume, aorta attenuation, extravasation attenuation and time) were input into a mathematical model to calculate bleeding rate.Fifty consecutive patients including 6 (12%) upper, 18 (36%) small bowel, and 26 (52%) lower GIB met inclusion criteria. Forty-two underwent catheter angiography, endoscopy, or surgery; 16 had intraprocedural active bleeding, and 24 required hemostatic therapy. Higher extravasation volumes correlated with hemostatic therapy (P = 0.007), intraprocedural active bleeding (P = 0.003), and massive transfusion (P = 0.0001), but not mortality (P = 0.936). Using a threshold volume of 0.80 mL or greater, the odds ratio of hemostatic therapy was 8.1 (95% confidence interval, 2.1-26), active bleeding was 11.8 (2.6-45), and massive transfusion was 18 (2.3-65). With mathematical modeling, extravasation volume had a direct and linear relationship with bleeding rate, and the lowest calculated detectable bleeding rate with CTA was less than 0.1 mL/min.Larger extravasation volumes correlate with higher bleeding rates and may identify patients who require hemostatic therapy, have intraprocedural bleeding, and require blood transfusions. Current CTAs can detect bleeding rates less than 0.1 mL/min.
View details for DOI 10.1097/RLI.0000000000000753
View details for PubMedID 33449577
Comparison of Opioid Medication Use after Conventional Chemoembolization versus Drug-Eluting Embolic Chemoembolization.
Journal of vascular and interventional radiology : JVIR
PURPOSE: To assess the use of opioid analgesics and/or antiemetic drugs for pain and nausea following selective chemoembolization with doxorubicin-based conventional (c)-transarterial chemoembolization versus drug-eluting embolic (DEE)-transarterial chemoembolization for hepatocellular carcinoma (HCC).MATERIALS AND METHODS: From October 2014 to 2016, 283 patients underwent 393 selective chemoembolization procedures including 188 patients (48%) who underwent c-transarterial chemoembolization and 205 (52%) who underwent DEE-transarterial chemoembolization. Medical records for all patients were retrospectively reviewed. Administration of postprocedural opioid and/or antiemetic agents were collated. Time of administration was stratified as phase 1 recovery (0-6 hours) and observation (6-24 hours). Logistic regression model was used to investigate the relationship of transarterial chemoembolization type and use of intravenous and/or oral analgesic and antiemetic medications while controlling for other clinical variables.RESULTS: More patients treated with DEE-transarterial chemoembolization required intravenous analgesia in the observation (6-24 hours) phase (18.5%) than those treated with c-transarterial chemoembolization (10.6%; P= .033). Similar results were noted for oral analgesic agents (50.2% vs. 31.4%, respectively; P < .001) and antiemetics (17.1% vs. 7.5%, respectively; P= .006) during the observation period. Multivariate regression models identified DEE-transarterial chemoembolization as an independent predictor for oral analgesia (odds ratio [OR], 1.84; P= .011), for intravenous and oral analgesia in opioid-naive patients (OR, 2.46; P= .029) and for antiemetics (OR, 2.56; P= .011).CONCLUSIONS: Compared to c-transarterial chemoembolization, DEE-transarterial chemoembolization required greater amounts of opioid analgesic and antiemetic agents 6-24 hours after the procedure. Surgical data indicate that a persistent opioid habit can develop even after minor surgeries, therefore, caution should be exercised, and a regimen of nonopiate pain medications should be considered to reduce postprocedural pain after transarterial chemoembolization.
View details for DOI 10.1016/j.jvir.2020.04.018
View details for PubMedID 32654960
Interreader Variability in Semantic Annotation of Microvascular Invasion in Hepatocellular Carcinoma on Contrast-enhanced Triphasic CT Images.
Radiology. Imaging cancer
2020; 2 (3): e190062
Purpose: To evaluate interreader agreement in annotating semantic features on preoperative CT images to predict microvascular invasion (MVI) in patients with hepatocellular carcinoma (HCC).Materials and Methods: Preoperative, contrast material-enhanced triphasic CT studies from 89 patients (median age, 64 years; age range, 36-85 years; 70 men) who underwent hepatic resection between 2008 and 2017 for a solitary HCC were reviewed. Three radiologists annotated CT images obtained during the arterial and portal venous phases, independently and in consensus, with features associated with MVI reported by other investigators. The assessed factors were the presence or absence of discrete internal arteries, hypoattenuating halo, tumor-liver difference, peritumoral enhancement, and tumor margin. Testing also included previously proposed MVI signatures: radiogenomic venous invasion (RVI) and two-trait predictor of venous invasion (TTPVI), using single-reader and consensus annotations. Cohen (two-reader) and Fleiss (three-reader) kappa and the bootstrap method were used to analyze interreader agreement and differences in model performance, respectively.Results: Of HCCs assessed, 32.6% (29 of 89) had MVI at histopathologic findings. Two-reader agreement, as assessed by pairwise Cohen kappa statistics, varied as a function of feature and imaging phase, ranging from 0.02 to 0.6; three-reader Fleiss kappa varied from -0.17 to 0.56. For RVI and TTPVI, the best single-reader performance had sensitivity and specificity of 52% and 77% and 67% and 74%, respectively. In consensus, the sensitivity and specificity for the RVI and TTPVI signatures were 59% and 67% and 70% and 62%, respectively.Conclusion: Interreader variability in semantic feature annotation remains a challenge and affects the reproducibility of predictive models for preoperative detection of MVI in HCC.Supplemental material is available for this article.© RSNA, 2020.
View details for DOI 10.1148/rycan.2020190062
View details for PubMedID 32550600
The biomechanical impact of hip movement on iliofemoral venous anatomy and stenting for deep venous thrombosis.
Journal of vascular surgery. Venous and lymphatic disorders
BACKGROUND: Stenting of the iliofemoral vein may be an effective treatment to improve post-thrombotic symptoms. Iliofemoral vein stents have requirements different from those of lower extremity artery stents, and there is a paucity of literature regarding the biomechanical motion of the iliofemoral vein.METHODS: In a novel cadaveric model, stents were bilaterally inserted into the veins in the iliofemoral region. The veins were pressurized and underwent computed tomography angiography at various hip angle positions. In addition, 21 patients with iliofemoral vein disease had supine computed tomography angiography before and after stenting. The stents and vasculature were reconstructed into three-dimensional geometric models to quantify stent deformations and the interaction between the iliofemoral vein, inguinal ligament, and pubis bone due to hip flexion-extension.RESULTS: In the cadavers, from supine to 30 to 45 degrees and 50 to 75 degrees of hip flexion, iliofemoral vein stents became less compressed (4.5% minor diameter expansion), and the inguinal ligament was separated from the iliofemoral veins by 1 to 3cm in all hip positions. In the patients, the pubis compressed 47% of femoral veins; 78% were within 3mm of the pubis. There was also evidence of contrast-enhanced flow disruption at the superior ramus.CONCLUSIONS: The cadaver and clinical evidence shows that contrary to widely accepted dogma, the common femoral vein is not compressed by the inguinal ligament during hip flexion but rather by the superior ramus of the pubis during hip extension, which may have an impact on future stent design and influence deep venous thrombosis treatment strategies.
View details for DOI 10.1016/j.jvsv.2020.01.022
View details for PubMedID 32321693
Iliofemoral Vein Compression Is Caused by the Pubic Bone, Not the Inguinal Ligament
ELSEVIER SCIENCE INC. 2019: B558
View details for Web of Science ID 000487306300559
Lower Extremity Venous Stent Placement: A Large Retrospective Single-Center Analysis.
Journal of vascular and interventional radiology : JVIR
PURPOSE: To study short-term and long-term outcomes of lower extremity venous stents placed at a single center and to characterize changes in vein diameter achieved by stent placement.MATERIALS AND METHODS: A database of all patients who received lower extremity venous stents between 1996 and 2018 revealed 1,094 stents were placed in 406 patients (172 men, 234 women; median age, 49 y) in 513 limbs, including patients with iliocaval stents (9.4% acute thrombosis, 65.3% chronic thrombosis, 25.3% nonthrombotic lesions). Primary, primary assisted, and secondary patency rates were assessed for lower extremity venous stents at 1, 3, and 5 years using Kaplan-Meier analyses and summary statistics. Subset analyses and Cox regression were performed to identify risk factors for patency loss. Vein diameters and Villalta scores before and up to 12 months after stent placement were compared. Complication and mortality rates were calculated.RESULTS: Primary, primary assisted, and secondary patency rates at 5 years were 57.3%, 77.2%, and 80.9% by Kaplan-Meier methods and 78.6%, 90.3%, and 92.8% by summary statistics. Median follow-up was 199 days (interquartile range, 35.2-712.0 d). Patency rates for the subset of patients (n= 46) with ≥ 5 years of follow-up (mean ± SD 9.1 y ± 3.4) were nearly identical to cohort patency rates at 5 years. Patients with inferior vena cava stent placement (hazard ratio 2.11, P < .0001) or acute thrombosis (hazard ratio 3.65, P < .0001) during the index procedure had significantly increased risk of losing primary patency status. Vein diameters were significantly greater after stent placement. There were no instances of stent fracture, migration, or structural deformities. In patients with chronic deep vein thrombosis, Villalta scores significantly decreased after stent placement (from 15.7 to 7.4, P < .0001). Perioperative mortality was < 1%, and major perioperative complication rate was 3.7%.CONCLUSIONS: Cavo-ilio-femoral stent placement for venous occlusive disease achieves improvement of vein disease severity scores, increase in treated vein diameters, and satisfactory long-term patency rates.
View details for DOI 10.1016/j.jvir.2019.06.011
View details for PubMedID 31542273
Custom 3-Dimensional Printed Ultrasound-Compatible Vascular Access Models: Training Medical Students for Vascular Access.
Journal of vascular and interventional radiology : JVIR
2019; 30 (6): 922–27
PURPOSE: To generate 3-dimensional (3D) printed ultrasound (US)-compatible vascular models (3DPVAM) and test them for noninferiority in training medical students in femoral artery access.MATERIALS AND METHODS: A 3DPVAM of normal femoral artery (FA) anatomy was developed from an anonymized computerized tomography (CT) examination. Students were randomized to a 3DPVAM or a commercial model (CM) simulation experience (SE) for US-guided FA access. Students completed a pre-SE questionnaire ranking their self-confidence in accessing the artery on a 5-point Likert scale. A standardized SE was administered by interventional radiology faculty or trainees. Students completed a post-SE questionnaire ranking comfort with FA access on a Likert scale. Student questionnaire results from the 3DPVAM group were compared with those from the CM group by using chi-square, Wilcoxon signed-rank, and noninferiority analyses.RESULTS: Twenty-six and twenty-three students were randomized to 3DPVAM and commercial model training, respectively. A total of 76.9% of 3DPVAM trainees and 82.6% of CM trainees did not feel confident performing FA access prior to the SE. In both groups, training increased student confidence by 2 Likert points (3DPVAM: P < 0.001; CM P < 0.001). The confidence increase in 3DPVAM trainees was noninferior to that in CM trainees (P < 0.001).CONCLUSIONS: Generation of a custom-made 3DPVAM is feasible, producing comparable subjective training outcomes to those of CM. Custom-made 3D-printed training models, including incorporation of more complex anatomical configurations, could be used to instruct medical students in procedural skills.
View details for DOI 10.1016/j.jvir.2019.02.011
View details for PubMedID 31126603
- A Predictive Model for Postembolization Syndrome after Transarterial Hepatic Chemoembolization of Hepatocellular Carcinoma RADIOLOGY 2019; 290 (1): 254–61
A Predictive Model for Postembolization Syndrome after Transarterial Hepatic Chemoembolization of Hepatocellular Carcinoma.
Purpose To develop and validate a predictive model for postembolization syndrome (PES) following transarterial hepatic chemoembolization (TACE) for hepatocellular carcinoma. Materials and Methods In this single-center, retrospective study, 370 patients underwent 513 TACE procedures between October 2014 and September 2016. Seventy percent of the patients were randomly assigned to a training data set and the remaining 30% were assigned to a testing data set. Variables included demographic, laboratory, clinical, and procedural details. PES was defined as pain and/or nausea beyond 6 hours after TACE that required intravenous medication for symptom control. The predictive model was developed by using conditional inference trees and Lasso regression. Results Demographics, laboratory data, performance, tumor characteristics, and procedural details were statistically similar for the training and testing data sets. Overall, 83 of 370 patients (22.4%) after 107 of 513 TACE procedures (20.8%) met the predefined criteria. Factors identified at univariable analysis included large tumor burden (P = .004), drug-eluting embolic TACE (P = .03), doxorubicin dose (P = .003), history of PES (P < .001) and chronic pain (P < .001), of which history of PES, tumor burden, and drug-eluting embolic TACE were identified as the strongest predictors by the multivariable analysis and were used to develop the predictive model. When applied to the testing data set, the model demonstrated an area under the curve of 0.62, sensitivity of 79% (22 of 28), specificity of 44.2% (53 of 120), and a negative predictive value of 90% (53 of 59). Conclusion The model identified history of postembolization syndrome, tumor burden, and drug-eluting embolic chemoembolization as predictors of protracted recovery because of postembolization syndrome. © RSNA, 2018.
View details for PubMedID 30299233
Determining the Optimal Number of Core Needle Biopsy Passes for Molecular Diagnostics
CARDIOVASCULAR AND INTERVENTIONAL RADIOLOGY
2018; 41 (3): 489–95
The number of core biopsy passes required for adequate next-generation sequencing is impacted by needle cut, needle gauge, and the type of tissue involved. This study evaluates diagnostic adequacy of core needle lung biopsies based on number of passes and provides guidelines for other tissues based on simulated biopsies in ex vivo porcine organ tissues.The rate of diagnostic adequacy for pathology and molecular testing from lung biopsy procedures was measured for eight operators pre-implementation (September 2012-October 2013) and post-implementation (December 2013-April 2014) of a standard protocol using 20-gauge side-cut needles for ten core biopsy passes at a single academic hospital. Biopsy pass volume was then estimated in ex vivo porcine muscle, liver, and kidney using side-cut devices at 16, 18, and 20 gauge and end-cut devices at 16 and 18 gauge to estimate minimum number of passes required for adequate molecular testing.Molecular diagnostic adequacy increased from 69% (pre-implementation period) to 92% (post-implementation period) (p < 0.001) for lung biopsies. In porcine models, both 16-gauge end-cut and side-cut devices require one pass to reach the validated volume threshold to ensure 99% adequacy for molecular characterization, while 18- and 20-gauge devices require 2-5 passes depending on needle cut and tissue type.Use of 20-gauge side-cut core biopsy needles requires a significant number of passes to ensure diagnostic adequacy for molecular testing across all tissue types. To ensure diagnostic adequacy for molecular testing, 16- and 18-gauge needles require markedly fewer passes.
View details for PubMedID 29279975
The Role of Cone-Beam CT in Transcatheter Arterial Chemoembolization for Hepatocellular Carcinoma: A Systematic Review and Meta-analysis.
Journal of vascular and interventional radiology
2017; 28 (3): 334-341
To review available evidence for use of cone-beam CT during transcatheter arterial chemoembolization in hepatocellular carcinoma (HCC) for detection of tumor and feeding arteries.Literature searches were conducted from inception to May 15, 2016, in PubMed (MEDLINE), Scopus, and Cochrane Central Register of Controlled Trials. Searches included "cone beam," "CBCT," "C-arm," "CACT," "cone-beam CT," "volumetric CT," "volume computed tomography," "volume CT," AND "liver," "hepatic*," "hepatoc*." Studies that involved adults with HCC specifically and treated with transcatheter arterial chemoembolization that used cone-beam CT were included.Inclusion criteria were met by 18 studies. Pooled sensitivity of cone-beam CT for detecting tumor was 90% (95% confidence interval [CI], 82%-95%), whereas pooled sensitivity of digital subtraction angiography (DSA) for tumor detection was 67% (95% CI, 51%-80%). Pooled sensitivity of cone-beam CT for detecting tumor feeding arteries was 93% (95% CI, 91%-95%), whereas pooled sensitivity of DSA was 55% (95% CI, 36%-74%).Cone-beam CT can significantly increase detection of tumors and tumor feeding arteries during transcatheter arterial chemoembolization. Cone-beam CT should be considered as an adjunct tool to DSA during transcatheter arterial chemoembolization treatments of HCC.
View details for DOI 10.1016/j.jvir.2016.11.037
View details for PubMedID 28109724
Noninvasive radiomics signature based on quantitative analysis of computed tomography images as a surrogate for microvascular invasion in hepatocellular carcinoma: a pilot study.
Journal of medical imaging (Bellingham, Wash.)
2017; 4 (4): 041303
We explore noninvasive biomarkers of microvascular invasion (mVI) in patients with hepatocellular carcinoma (HCC) using quantitative and semantic image features extracted from contrast-enhanced, triphasic computed tomography (CT). Under institutional review board approval, we selected 28 treatment-naive HCC patients who underwent surgical resection. Four radiologists independently selected and delineated tumor margins on three axial CT images and extracted computational features capturing tumor shape, image intensities, and texture. We also computed two types of "delta features," defined as the absolute difference and the ratio computed from all pairs of imaging phases for each feature. 717 arterial, portal-venous, delayed single-phase, and delta-phase features were robust against interreader variability ([Formula: see text]). An enhanced cross-validation analysis showed that combining robust single-phase and delta features in the arterial and venous phases identified mVI (AUC [Formula: see text]). Compared to a previously reported semantic feature signature (AUC 0.47 to 0.58), these features in our cohort showed only slight to moderate agreement (Cohen's kappa range: 0.03 to 0.59). Though preliminary, quantitative analysis of image features in arterial and venous phases may be potential surrogate biomarkers for mVI in HCC. Further study in a larger cohort is warranted.
View details for PubMedID 28840174
Standardized Reporting in IR: A Prospective Multi-Institutional Pilot Study
JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY
2016; 27 (12): 1779-1785
To assess adoption and survey-based satisfaction rates following deployment of standardized interventional radiology (IR) procedure reports across multiple institutions.Standardized reporting templates for 5 common interventional procedures (central venous access, inferior vena cava [IVC] filter insertion, IVC filter removal, uterine artery embolization, and vertebral augmentation) were distributed to 20 IR practices in a prospective quality-improvement study. Participating sites edited the reports according to institutional preferences and deployed them for a 1-year pilot study concluding in July 2015. Study compliance was measured by sampling 20 reports of each procedure type at each institution, and surveys of interventionalists and referring physicians were performed. Modifications to the standardized reporting templates at each site were analyzed.Ten institutions deployed the standardized reports, with 8 achieving deployment of 3-12 months. The mean report usage rate was 57%. Each site modified the original reports, with 26% mean reduction in length, 18% mean reduction in wordiness, and 60% mean reduction in the number of forced fill-in fields requiring user input. Linear-regression analysis revealed that reduced number of forced fill-in fields correlated significantly with increased usage rate (R(2) = 0.444; P = .05). Surveys revealed high satisfaction rates among referring physicians but lower satisfaction rates among interventional radiologists.Standardized report adoption rates increased when reports were simplified by reducing the number of forced fill-in fields. Referring physicians preferred the standardized reports, whereas interventional radiologists preferred standard narrative reports.
View details for DOI 10.1016/j.jvir.2016.07.016
View details for PubMedID 27670943
Complications During Transjugular Intrahepatic Portosystemic Shunt Creation.
Techniques in vascular and interventional radiology
2016; 19 (1): 61-73
Transjugular intrahepatic portosystemic shunt (TIPS) creation is a widely adopted treatment for complications of portal hypertension, including variceal hemorrhage and refractory ascites. The creation of a TIPS requires establishing a pathway from the portal vein to a hepatic vein or inferior vena cava through hepatic parenchyma, using a stent or stent graft to sustain patency of this pathway. Because it is a technically challenging procedure and patients may be critically ill with severe comorbidities, the risk of procedural complications and mortality is substantial. This article discusses known complications of the TIPS procedure and ways to minimize their occurrence.
View details for DOI 10.1053/j.tvir.2016.01.007
View details for PubMedID 26997090
Endovascular Stent Placement for May-Thurner Syndrome in the Absence of Acute Deep Vein Thrombosis.
Journal of vascular and interventional radiology
2016; 27 (2): 167-173
To assess the clinical utility of iliac vein stent placement for patients with chronic limb edema or pelvic congestion presenting with nonocclusive May-Thurner physiology.All patients (N = 45) undergoing stent placement for May-Thurner syndrome (MTS) without an associated acute thrombotic event between 2007 and 2014 were retrospectively reviewed; 11 were excluded for poor follow-up. A total of 34 patients (28 female) were studied (mean age, 44 y; range, 19-80 y). Average follow-up time was 649 days (median, 488 d; range, 8-2,499 d).The technical success rate was 100% (34 of 34). No major and two minor (5%) complications occurred, and 68% of patients (23 of 34) had clinical success with relief of presenting symptoms on follow-up visits. Technical parameters including stent size and number, stent type, concurrent angioplasty, access site, and resolution of collateral iliolumbar vessels were not found to be statistically related to clinical success (P > .05). Similarly, no significant relation to clinical success was seen for clinical factors such as the type of symptoms, presence of chronic deep vein thrombosis (DVT), or concurrent coagulopathy (P > .05). Female sex was found to correlate with clinical success (82% vs 18%; P = .04).Iliac stent placement in patients presenting with chronic limb or pelvic symptoms from MTS without acute DVT is associated with clinical success in the majority of patients.
View details for DOI 10.1016/j.jvir.2015.10.028
View details for PubMedID 26703783
- Severe Chest Wall Toxicity From Cryoablation in the Setting of Prior Stereotactic Ablative Radiotherapy CUREUS 2016; 8 (2)
Severe Chest Wall Toxicity From Cryoablation in the Setting of Prior Stereotactic Ablative Radiotherapy.
2016; 8 (2)
We present the case of a 42-year-old woman with metastatic synovial sarcoma of parotid origin, treated definitively with chemoradiation, who subsequently developed oligometastatic disease limited to the lungs. She underwent multiple left and right lung wedge resections and left lower lobectomy, followed by right lower lobe stereotactic ablative radiotherapy (SABR), 54 Gy in three fractions to a right lower lobe lesion abutting the chest wall. Two years later, she was treated with cryoablation for a separate right upper lobe nodule abutting the chest wall. Two months later, she presented with acute shortness of breath, pleuritic chest pain, decreased peripheral blood O2 saturation, and productive cough. A computed tomography (CT) scan demonstrated severe chest wall necrosis in the area of recent cryoablation that, in retrospect, also received a significant radiation dose from her prior SABR. This case demonstrates that clinicians should exercise caution in using cryoablation when treating lung tumors abutting a previously irradiated chest wall. Note: Drs. Loo and Shah contributed equally as co-senior authors.
View details for DOI 10.7759/cureus.477
View details for PubMedID 27004154
View details for PubMedCentralID PMC4780688
Management of High Hepatopulmonary Shunting in Patients Undergoing Hepatic Radioembolization.
Journal of vascular and interventional radiology
2015; 26 (12): 1751-1760
To review the safety of hepatic radioembolization (RE) in patients with high (≥ 10%) hepatopulmonary shunt fraction (HPSF) using various prophylactic techniques.A review was conducted of 409 patients who underwent technetium 99m-labeled macroaggregated albumin scintigraphy before planned RE. Estimated pulmonary absorbed radiation doses based on scintigraphy and hepatic administered activity were calculated. Outcomes from dose reductions and adjunctive catheter-based prophylactic techniques used to reduce lung exposure were assessed.There were 80 patients with HPSF ≥ 10% who received RE treatment (41 resin microspheres for metastases, 39 glass microspheres for hepatocellular carcinoma). Resin microspheres were used in 17 patients according to consensus guideline-recommended dose reduction; 38 patients received no dose reduction because the expected lung dose was < 30 Gy. Prophylactic techniques were used in 25 patients (with expected lung dose ≤ 74 Gy), including hepatic vein balloon occlusion, variceal embolization, or bland arterial embolization before, during, or after RE delivery. Repeated scintigraphy after prophylactic techniques to reduce HPSF in seven patients demonstrated a median change of -40% (range, +32 to -69%). Delayed pneumonitis developed in two patients, possibly related to radiation recall after chemoembolization. Response was lower in patients treated with resin spheres with dose reduction, with an objective response rate of 13% and disease control rate of 47% compared with 56% and 94%, respectively, without dose reduction (P = .023, P = .006).Dose reduction recommendations for HPSF may compromise efficacy. Excessive shunting can be reduced by prophylactic catheter-based techniques, which may improve the safety of performing RE in patients with high HPSF.
View details for DOI 10.1016/j.jvir.2015.08.027
View details for PubMedID 26525118
Core samples for radiomics features that are insensitive to tumor segmentation: method and pilot study using CT images of hepatocellular carcinoma.
Journal of medical imaging (Bellingham, Wash.)
2015; 2 (4): 041011-?
The purpose of this study is to investigate the utility of obtaining "core samples" of regions in CT volume scans for extraction of radiomic features. We asked four readers to outline tumors in three representative slices from each phase of multiphasic liver CT images taken from 29 patients (1128 segmentations) with hepatocellular carcinoma. Core samples were obtained by automatically tracing the maximal circle inscribed in the outlines. Image features describing the intensity, texture, shape, and margin were used to describe the segmented lesion. We calculated the intraclass correlation between the features extracted from the readers' segmentations and their core samples to characterize robustness to segmentation between readers, and between human-based segmentation and core sampling. We conclude that despite the high interreader variability in manually delineating the tumor (average overlap of 43% across all readers), certain features such as intensity and texture features are robust to segmentation. More importantly, this same subset of features can be obtained from the core samples, providing as much information as detailed segmentation while being simpler and faster to obtain.
View details for DOI 10.1117/1.JMI.2.4.041011
View details for PubMedID 26587549
- Quantitative Emphysema Score as a Predictor of Morbidity in Transthoracic Needle Aspiration Biopsy AMER COLL CHEST PHYSICIANS. 2015
- Corrigendum to "Asymptomatic Liver Abscesses Mimicking Metastases in Patients after Whipple Surgery: Infectious Complications following Percutaneous Biopsy-A Report of Two Cases". Case reports in hepatology 2015; 2015: 783506
Prophylactic Topically Applied Ice to Prevent Cutaneous Complications of Nontarget Chemoembolization and Radioembolization
JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY
2013; 24 (4): 596-600
Cutaneous complications can result from nontarget deposition during transcatheter arterial chemoembolization or radioembolization. Liver tumors may receive blood supply from parasitized extrahepatic arteries (EHAs) that also perfuse skin or from hepatic arteries located near the origin of the falciform artery (FA), which perfuses the anterior abdominal wall. To vasoconstrict cutaneous vasculature and prevent nontarget deposition, ice packs were topically applied to at-risk skin in nine chemoembolization treatments performed via 14 parasitized EHAs, seven chemoembolization treatments near the FA origin, and five radioembolization treatments in cases in which the FA could not be prophylactically coil-embolized. No postprocedural cutaneous complications were encountered.
View details for DOI 10.1016/j.jvir.2012.12.020
View details for PubMedID 23522163
Superselective Internal Radiation With Yttrium-90 Microspheres in the Management of a Chemorefractory Testicular Liver Metastasis
CARDIOVASCULAR AND INTERVENTIONAL RADIOLOGY
2012; 35 (2): 426-429
We treated a patient with biopsy-proven, chemotherapy-resistant testicular cancer liver metastasis using Y-90 selective internal radiation treatment. We chose yttrium-90 rather than surgery and ablation due to tumor location and size as well as the patient's clinical history. The result was marked tumor response by positron emission tomography and computed tomography as well as significant improvement of the patient's quality of life accompanied by a substantial decrease of his tumor markers.
View details for DOI 10.1007/s00270-011-0226-7
View details for Web of Science ID 000304162400029
View details for PubMedID 21773859
Asymptomatic Liver Abscesses Mimicking Metastases in Patients after Whipple Surgery: Infectious Complications following Percutaneous Biopsy-A Report of Two Cases.
Case reports in hepatology
2012; 2012: 817314-?
We present two cases of hepatic abscesses that mimicked metastases in patients having undergone Whipple surgery. Both patients had similar imaging features on computed tomographic (CT) scan and ultrasound, and at the time of referral for biopsy neither patient was clinically suspected to have liver abscess. Both patients underwent biopsy of liver lesions and developed postprocedural infectious complications.
View details for DOI 10.1155/2012/817314
View details for PubMedID 25374711
View details for PubMedCentralID PMC4208445
Cystic Artery Localization with a Three-dimensional Angiography Vessel Tracking System Compared with Conventional Two-dimensional Angiography
JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY
2011; 22 (10): 1414-1419
During transcatheter hepatic therapy, the cystic artery feeding the gallbladder may inadvertently be exposed to tumor therapy. Localization of the cystic artery may help prevent exposure. The objective of this study was to compare the application of a vessel tracking system software based on three-dimensional (3D) angiography versus standard two-dimensional (2D) angiography for identifying the cystic artery and its origin.A software system that can rapidly localize the cystic artery from a 3D common hepatic angiogram was applied in 25 patients and was compared with manual localization of the cystic artery with conventional 2D digital subtraction common hepatic angiograms.With the vessel tracking software prototype, 28 cystic arteries were retrogradely tracked in 25 of 25 cases. The origin sites were correctly located by the software in 27 of 28 cystic arteries, with one mistracked as a result of streak artifact. By contrast, on standard 2D hepatic angiography, the cystic artery was deemed visible with certainty in 12 of 25 cases (P < .001). The vessel tracking system revealed a 56% prevalence of extraanatomic distribution by the cystic artery, with the most common supply going to segment 5 liver parenchyma.The 3D vessel rapid tracking system has advantages over conventional 2D hepatic angiography in revealing the cystic artery and its origin site. It is also an important tool to identify the complete distribution of the cystic artery without superselective angiography. Supply to adjacent hepatic parenchyma or tumor by the cystic artery is not insignificant and should be considered during hepatic therapies.
View details for DOI 10.1016/j.jvir.2011.02.022
View details for Web of Science ID 000295708400011
View details for PubMedID 21546264
Arterially Directed Therapies for Hepatocellular Carcinoma
AMERICAN JOURNAL OF ROENTGENOLOGY
2011; 197 (4): W590-W602
Arterially directed therapies for hepatocellular carcinoma are used for patients who are not candidates for surgery or ablation and for those who need a bridge or down-staging to liver transplantation. These therapies seem to prolong the overall survival when compared with supportive care.Chemoembolization, particle embolization, drug-eluting beads, and radioembolization have been used for locoregional control. This review discusses patient selection, techniques, safety, clinical outcomes, and imaging findings related to these therapies.
View details for DOI 10.2214/AJR.11.7554
View details for Web of Science ID 000295081000008
View details for PubMedID 21940531
Hepatic arterial embolization complicated by acute cholecystitis.
Seminars in interventional radiology
2011; 28 (2): 252-257
Hepatic arterial embolization (HAE) is a treatment used in the management of primary and some metastatic hepatic tumors. Complications of HAE are similar to those seen in other treatments, particularly transcatheter arterial chemoembolization (TACE), but without the possibility for chemotherapy related side effects. Particle reflux into the cystic artery is generally clinically occult but gallbladder ischemia severe enough to require cholecystostomy tube placement can occur. The authors discuss the case of a patient who underwent HAE and subsequently required a cholecystostomy tube due to development of acute cholecystitis.
View details for DOI 10.1055/s-0031-1280675
View details for PubMedID 22654273
Synchronous moyamoya syndrome and ruptured cerebral aneurysm in Alagille syndrome
JOURNAL OF CLINICAL NEUROSCIENCE
2008; 15 (12): 1395-1398
Moyamoya syndrome and cerebral aneurysm formation are rare cerebrovascular manifestations of Alagille syndrome. Although previously reported in isolation, occurrence of these complications in a single patient has not been described. We report clinical and imaging features of synchronous moyamoya syndrome and ruptured cerebral aneurysm in a patient with Alagille syndrome.
View details for DOI 10.1016/j.jocn.2007.05.033
View details for Web of Science ID 000264181800018
View details for PubMedID 18842413
A case of pancreatic islet cell transplantation in a patient with situs ambiguous: anatomical and radiological considerations.
Seminars in interventional radiology
2007; 24 (1): 43-46
Pancreatic islet cell transplantation is an evolving treatment of severe, refractory type 1 diabetes that has been gaining more use, particularly after one year rates of insulin independence post-transplantation were found to approach 80% under the Edmonton protocol. Islet cell transplantation involves percutaneous delivery of harvested allogeneic β cells into the portal venous circulation for implantation into the liver. We present the case of a 35-year-old woman with type 1 diabetes and situs ambiguous with left isomerism and resultant variant anatomy of her portal venous anatomy who underwent islet cell transplantation, which, to our knowledge, has not been previously reported.
View details for DOI 10.1055/s-2007-971190
View details for PubMedID 21326735