Clinical Focus

  • Cancer
  • Radiology
  • Vascular and Interventional Radiology

Academic Appointments

  • Clinical Professor, Radiology
  • Member, Bio-X

Administrative Appointments

  • Associate Chair, Clinical Performance Improvement, Department of Radiology (2019 - Present)
  • Medical Informatics Director and Chair of Radiology IT Operations Committee, Department of Radiology (2020 - Present)
  • Associate Program Director, Department of Radiology (2015 - Present)
  • Director of Clinical Performance Improvement, Department of Radiology (2018 - 2019)

Honors & Awards

  • Magna Cum Laude, Harvard University (1996)
  • Featured Abstract, SIR Annual Meeting (2001)
  • Norman Blank Award for Excellence in Radiology, Stanford University (2001)
  • Stanford University Medical Center Dept. of Surgery 90th Percentile Award, Stanford University (2002)
  • RSNA/AUR/ARRS Introduction to Research Program Scholarship, RSNA/AUR/ARRS (2003)
  • Molecular Biology for Imagers course scholarship, AUR (2005)
  • Chief Resident, Dept. of Radiology, Stanford University (2004-2005)
  • RSNA Roentgen Resident/Fellow Research Award, RSNA (2007)

Professional Education

  • Board Certification: American Board of Radiology, Interventional Radiology and Diagnostic Radiology (2017)
  • Fellowship: Stanford University Hospital (2008) CA
  • Residency: Stanford University - Fellowship (2006) CA
  • BA, Harvard College, Biochemical Sciences (1996)
  • Medical Education: Stanford University School of Medicine (2001) CA
  • Internship: Stanford Hospital and Clinics - Dept of Surgery (2002) CA
  • Subspecialty Certificate, American Board of Radiology, Interventional Radiology (2010)

Current Research and Scholarly Interests

Interventional oncology, pancreatic interventions, image-guided gene therapy.

Clinical Trials

  • Filter Initial & Long Term Evaluation After Placement and Retrieval Registry Recruiting

    A prospective data registry for all patients who undergo IVC (Inferior Vena Cava) filter placement or retrieval at Stanford. Potential enrollees will already be undergoing the procedure. If patients are willing, they will be prospectively enrolled prior to the procedure. As part of the study, chart and clinical data reviews will be used to track patient progress and response to the treatment.

    View full details

  • A Phase 2b Study of Modified Vaccinia Virus to Treat Patients Advanced Liver Cancer Who Failed Sorafenib Not Recruiting

    This study is to determine whether JX-594 (Pexa-Vec) plus best supportive care is more effective in improving survival than best supportive care in patients with advanced Hepatocellular Carcinoma (HCC) who have failed sorafenib.

    Stanford is currently not accepting patients for this trial. For more information, please contact Fizaa Ahmed, (650) 725 - 6409.

    View full details

  • Acute Venous Thrombosis: Thrombus Removal With Adjunctive Catheter-Directed Thrombolysis Not Recruiting

    The purpose of this study is to determine if the use of adjunctive Pharmacomechanical Catheter Directed Thrombolysis, which includes the intrathrombus administration of rt-PA--Activase (Alteplase),can prevent the post-thrombotic syndrome(PTS)in patients with symptomatic proximal deep vein thrombosis(DVT)as compared with optimal standard DVT therapy alone.

    Stanford is currently not accepting patients for this trial. For more information, please contact Kamil Unver, (650) 725 - 9810.

    View full details

  • ExAblate (MRgFUS) Treatment of Metastatic Bone Tumors for the Palliation of Pain Not Recruiting

    A Pivotal Study to Evaluate the Effectiveness and Safety of ExAblate Treatment of Metastatic Bone and Multiple Myeloma Tumors for the Palliation of Pain in Patients Who are not Candidates for Radiation Therapy

    Stanford is currently not accepting patients for this trial. For more information, please contact Kamil Unver, (650) 725 - 9810.

    View full details

  • HepaSphere/Quadrasphere Microspheres for Delivery of Doxorubicin for the Treatment of Hepatocellular Cancer Not Recruiting

    The purpose of this study is to evaluate overall survival in patients diagnosed with hepatocellular cancer (HCC) treated with HepaSphere/QuadraSphere Microspheres loaded with chemotherapeutic agent doxorubicin compared to conventional transarterial chemoembolization with particle PVA, lipiodol, and doxorubicin.

    Stanford is currently not accepting patients for this trial. For more information, please contact Risa Jiron, 650-736-1598.

    View full details

  • Impact of C-arm CT in Decreased Renal Function Undergoing TACE for Tx of Hepato-Cellular Carcinoma Not Recruiting

    Impact on contrast dose or total volume of contrast required to effectively treat the targeted tumor.

    Stanford is currently not accepting patients for this trial. For more information, please contact Kamil Unver, (650) 725 - 9810.

    View full details

  • Impact of C-arm CT in Patients With HCC Undergoing TACE: Optimal Imaging Guidance Not Recruiting

    Patients will be enrolled based on presence of HCC and eligibility for TACE. They will be randomized to one of two arms for imaging navigation to the optimal catheter location for chemotherapy injection to treat the first (possibly sole) tumor target. The two arms will be: TACE using C-arm CT supplemented by DSA or DSA only (only DSA images will be used for navigation and tumor vessel tracking). Navigation to subsequent treatment targets in all patients will be done with fluoroscopy, CACT, and DSA, as is standard of care at Stanford University Medical Center, and is not part of the study. Vascular complexity, which affects navigation difficulty and thus the need for imaging, will be assessed separately for use in data analysis by two radiologists on a four-point scale.

    Stanford is currently not accepting patients for this trial. For more information, please contact Kamil Unver, (650) 725 - 9810.

    View full details

  • Pulmonary Embolism Response to Fragmentation, Embolectomy, & Catheter Thrombolysis: PERFECT Not Recruiting

    A prospective observational study to evaluate the safety and effectiveness data of catheter-directed therapy (CDT) including percutaneous mechanical thrombectomy (PMT) for treatment of acute pulmonary embolism (PE)

    Stanford is currently not accepting patients for this trial. For more information, please contact William Kuo, 650-724-7362.

    View full details

  • The GORE Viabahn Endoprosthesis for the Treatment of Venous Occlusions and Stenoses Not Recruiting

    To study the safety and efficacy of drug coated stents for the treatment of venous occlusions and stenoses in the lower extremity. The use of the device for the treatment of peripheral arterial disease is approved by the FDA, however, the use of the device in venous occlusions and stenoses, although performed by some practitioners, has not yet been studied in detail.

    Stanford is currently not accepting patients for this trial. For more information, please contact Kamil Unver, 650-725-9810.

    View full details

2023-24 Courses

All Publications

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


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

    View details for DOI 10.1016/j.radonc.2023.110079

    View details for PubMedID 38163486

  • From Acceptable to Superlative: Scaling a Technologist Coaching Intervention to Improve Image Quality. Journal of the American College of Radiology : JACR Hwang, G. L., Vilendrer, S., Amano, A., Brown-Johnson, C., Kling, S. M., Faust, A., Willis, M. H., Larson, D. B. 2023; 20 (6): 570-584


    To explore factors influencing the expansion of the peer-based technologist Coaching Model Program (CMP) from its origins in mammography and ultrasound to all imaging modalities at a single tertiary academic medical center.After success in mammography and ultrasound, efforts to expand the CMP across all Stanford Radiology modalities commenced in September 2020. From February to April 2021 as lead coaches piloted the program in these novel modalities, an implementation science team designed and conducted semistructured stakeholder interviews and took observational notes at learning collaborative meetings. Data were analyzed using inductive-deductive approaches informed by two implementation science frameworks.Twenty-seven interviews were collected across modalities with radiologists (n = 5), managers (n = 6), coaches (n = 11), and technologists (n = 5) and analyzed with observational notes from six learning meetings with 25 to 40 recurrent participants. The number of technologists, the complexity of examinations, or the existence of standardized auditing criteria for each modality influenced CMP adaptations. Facilitators underlying program expansion included cross-modality learning collaborative, thoughtful pairing of coach and technologist, flexibility in feedback frequency and format, radiologist engagement, and staged rollout. Barriers included lack of protected coaching time, lack of pre-existing audit criteria for some modalities, and the need for privacy of auditing and feedback data.Adaptations to each radiology modality and communication of these learnings were key to disseminating the existing CMP to new modalities across the entire department. An intermodality learning collaborative can facilitate the dissemination of evidence-based practices across modalities.

    View details for DOI 10.1016/j.jacr.2022.10.007

    View details for PubMedID 37302811

  • Current state of peer learning in radiology- A survey of American College of Radiology members. Journal of the American College of Radiology : JACR Sharpe, R. E., Tarrant, M. J., Brook, O. R., Chatfield, M., Chaudhry, H., City, R. B., Donnelly, L., Stein, S. G., Hernandez, D., Hwang, G. L., Kunst, M. M., Lee, R., Moriarity, A., Pahade, J. K., Patel, S., Broder, J. 2023


    PURPOSE: Peer learning (PL) programs seek to improve upon the limitations of score-based peer review and incorporate modern approaches to improve patient care. This study seeks to further understand the landscape of peer learning among members of the American College of Radiology in the first quarter of 2022.METHODS: Members of the American College of Radiology (ACR) were surveyed to evaluate the incidence, current practices, perceptions, and outcomes of PL in radiology practice. The survey was administered via email to 20,850 ACR members. The demographic and practice characteristics of the 1,153 (6%) respondents were similar to the ACR radiologist membership and correspond to a normal distribution of the population of radiologists and can therefore be described as representative of that population. Therefore, the error range for the results from this survey is +/- 2.9% at a 95% confidence level.RESULTS: Among the total sample, 610 (53%) respondents currently use PL, 334 (29%) do not. Users of PL are younger (mode age 45-54 for users, 55-64 for non-users, P<0.01), more likely to be female (29% vs 23%, P<0.05), and more likely to practice in urban settings (52% vs 40%, P= 0.0002). Users of PL feel it supports an improved culture of safety and wellness (543/610, 89%) and fosters continuous improvement initiatives (523/610, 86%). Users of PL are more likely than non-users to identify learning opportunities from routine clinical practice (83% vs. 50%, P<0.00001), engage in programming inclusive of more team members, and implement more practice improvement projects (P<0.00001). PL users' net promoter score of 65% strongly suggests that users of PL are highly likely to recommend the program to colleagues.DISCUSSION: Radiologists across a breadth of radiology practices are engaged in peer learning activities, which are perceived to align with emerging principles of improving healthcare and enhance culture, quality, and engagement.

    View details for DOI 10.1016/j.jacr.2023.03.018

    View details for PubMedID 37230234

  • Monitoring sarcoma response to immune checkpoint inhibition and local cryotherapy with circulating tumor DNA analysis. Clinical cancer research : an official journal of the American Association for Cancer Research Bui, N. Q., Nemat-Gorgani, N., Subramanian, A., Torres, I. A., Lohman, M., Sears, T. J., van de Rijn, M., Charville, G. W., Becker, H. C., Wang, D. S., Hwang, G. L., Ganjoo, K. N., Moding, E. J. 2023


    Immune checkpoint inhibition has led to promising responses in soft tissue sarcomas (STSs), but the majority of patients do not respond and biomarkers of response will be crucial. Local ablative therapies may augment systemic responses to immunotherapy. We evaluated circulating tumor DNA (ctDNA) as a biomarker of response in patients treated on a trial combining immunotherapy with local cryotherapy for advanced STSs.We enrolled 30 patients with unresectable or metastatic STS to a phase 2 clinical trial. Patients received ipilimumab and nivolumab for 4 doses followed by nivolumab alone with cryoablation performed between cycles 1 and 2. The primary endpoint was objective response rate (ORR) by 14 weeks. Personalized ctDNA analysis using bespoke panels was performed on blood samples collected prior to each immunotherapy cycle.ctDNA was detected in at least one sample for 96% of patients. Pre-treatment ctDNA allele fraction was negatively associated with treatment response, progression-free survival (PFS), and overall survival (OS). ctDNA increased in 90% of patients from pre-treatment to post-cryotherapy, and patients with a subsequent decrease in ctDNA or undetectable ctDNA after cryotherapy had significantly better PFS. Of the 27 evaluable patients, the ORR was 4% by RECIST and 11% by irRECIST. Median PFS and OS were 2.7 and 12.0 months, respectively. No new safety signals were observed.ctDNA represents a promising biomarker for monitoring response to treatment in advanced STS, warranting future prospective studies. Combining cryotherapy and immune checkpoint inhibitors did not increase the response rate of STSs to immunotherapy.

    View details for DOI 10.1158/1078-0432.CCR-23-0250

    View details for PubMedID 37130154

  • ACR Appropriateness Criteria Management of Liver Cancer: 2022 Update. Journal of the American College of Radiology : JACR Expert Panel on Interventional Radiology, Knavel Koepsel, E. M., Smolock, A. R., Pinchot, J. W., Kim, C. Y., Ahmed, O., Chamarthy, M. R., Hecht, E. M., Hwang, G. L., Kaplan, D. E., Luh, J. Y., Marrero, J. A., Monroe, E. J., Poultsides, G. A., Scheidt, M. J., Hohenwalter, E. J. 2022; 19 (11S): S390-S408


    The treatment and management of hepatic malignancies can be complex because it encompasses a variety of primary and metastatic malignancies and an assortment of local and systemic treatment options. When to use each of these treatments is critical to ensure the most appropriate care for patients. Interventional radiologists have a key role to play in the delivery of a variety of liver directed treatments including percutaneous ablation, transarterial embolization with bland embolic particles alone, transarterial chemoembolization (TACE) with injection of a chemotherapeutic emulsion, and transarterial radioembolization (TARE). Based on 9 clinical variants, the appropriateness of each treatment is described in this document. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

    View details for DOI 10.1016/j.jacr.2022.09.005

    View details for PubMedID 36436965

  • Opportunities for Excellence in Interventional Radiology Training: A Qualitative Study. Journal of the American College of Radiology : JACR Oladini, L., Rezaee, M., Thukral, S., Raiter, S., Odetoyinbo, K., Keller, E., Hwang, G. 2022


    The training experience in interventional radiology (IR) residency programs varies widely across the country. The introduction of an IR training pathway has provided the impetus for the specialty to better define outstanding IR education and for programs to rethink how their curricula prepare IR trainees for real-world practice. Although ACGME competencies define several training components that are necessary for independent practice, few quantitative or qualitative studies have explored current perceptions on what constitutes optimal IR training. Our goal was to qualitatively explore program training features deemed most important to adequately prepare IR physicians for practice and assess whether there were differences in perception between academic and nonacademic practices.Semistructured interviews were conducted with 71 IR attending physicians, trainees, and support staff across the United States. All interviews were performed over the telephone by a single researcher for consistency and systematically coded by two independent coders for common themes. Frequency and prevalence of themes and facilitating features were analyzed.The most frequently perceived facilitating features included longitudinal patient care experience, practice-building education, interspecialty collaboration exposure, broad case mix, clinical decision-making exposure, diagnostic radiology training, procedural skills training, and graduated autonomy. Comparing nonacademic versus academic practice settings, significantly more nonacademic IR attending physicians expressed practice-building education (prevalence 72% versus 42%, frequency 2.2 versus 0.7, P < .01) as an important training experience.An understanding of perceived facilitating features for optimal IR trainee preparation, including potentially different needs between academic and nonacademic practices, can help programs prepare their trainees for a successful transition into practice.

    View details for DOI 10.1016/j.jacr.2022.01.011

    View details for PubMedID 35240105

  • Safety and Feasibility of Cryoablation during Immunotherapy in Patients with Metastatic Soft Tissue Sarcoma. Journal of vascular and interventional radiology : JVIR Doshi, A., Zhou, M., Bui, N., Wang, D. S., Ganjoo, K., Hwang, G. L. 2021


    PURPOSE: Patients with metastatic soft tissue sarcoma (STS) undergo a wide array of treatments, including surgery, radiation, chemotherapy, immunotherapy, and ablative therapies, to control their disease. The combination of cryoablation and immunotherapy may lead to an enhanced anti-tumor immune response via the abscopal effect. It is hypothesized that the combination of cryoablation and immunotherapy in patients with metastatic STS is safe and feasible.MATERIALS/METHODS: A single-center retrospective analysis was performed on patients with metastatic STS who underwent cryoablation. Sixteen patients were treated with 27 cryoablation procedures while receiving ipilimumab and nivolumab from April 2017 to July 2020. RECIST 1.1 criteria was used to determine outcomes of non-target tumors. Progression-free survival (PFS) and overall survival (OS) were calculated from the date of first cryoablation after initiating immunotherapy until progression or death.RESULTS: Thirty-four tumors were cryoablated, 23 of which were intentionally subtotal. Most common tumor subtype was liposarcoma (n = 4). Thirteen patients (81%) had previously demonstrated disease progression on multiple lines of chemotherapy. All tumors cryoablated with complete intention demonstrated complete response. Seven patients had clinical benefit, including 1 complete response, 1 partial response, and 5 with stable disease. The median OS was 14.1 months, with a median PFS of 2.3 months (95% CI 1.8-14.3). Five patients had post-cryoablation pneumothoraces, two of whom required chest tube placement. Eleven patients experienced adverse events related to immunotherapy, 10 of which were grade 1 or 2.CONCLUSION: Cryoablation in patients with metastatic soft tissue sarcoma undergoing immunotherapy is feasible and safe.

    View details for DOI 10.1016/j.jvir.2021.08.017

    View details for PubMedID 34478852

  • Long-Term Remission with Ipilimumab/Nivolumab in Two Patients with Different Soft Tissue Sarcoma Subtypes and No PD-L1 Expression. Case reports in oncology Zhou, M., Bui, N., Lohman, M., van de Rjin, M., Hwang, G., Ganjoo, K. 2021; 14 (1): 459–65


    Checkpoint inhibitor therapy has been shown to improve outcomes in multiple solid malignancies; however, data are limited in soft tissue sarcoma. We present two cases of patients with advanced soft tissue sarcoma of different subtypes (dedifferentiated liposarcoma and myxofibrosarcoma) with zero percent PD-L1 expression by immunohistochemistry who were treated with ipilimumab and nivolumab followed by maintenance nivolumab. Both patients had failed multiple lines of systemic treatment and experienced long-term remission after starting ipilimumab and nivolumab. Genetic testing revealed that no genetic mutations were found in common between the two cases. One patient received concurrent cryoablation, which may have sensitized his tumor to immunotherapy. Checkpoint inhibitor therapy may improve outcomes in soft tissue sarcoma regardless of PD-L1 status, especially when combined with cryoablation. Studies are needed to evaluate whether treatment response varies by sarcoma subtype and what molecular markers can be used to guide patient selection.

    View details for DOI 10.1159/000512828

    View details for PubMedID 33790767

  • Recognizing and Avoiding the Most Common Mistakes in Quality Improvement. Journal of the American College of Radiology : JACR Larson, D. B., Willis, M. H., Hwang, G. L. 2020

    View details for DOI 10.1016/j.jacr.2020.09.053

    View details for PubMedID 33069677

  • Critical Results in Radiology: Defined by Clinical Judgment or by a List? Journal of the American College of Radiology : JACR Kuhn, K., Larson, D. B., 2020 Radiology Improvement Summit Critical Results Workgroup, Becker, C., Bierhals, A., Broder, J., City, R., Cooke, E., Cordova, D., Curci, N. E., Davenport, M. S., Dinan, D., Duncan, J. R., Dungan, D., Facchini, D., Heller, R. E., Hwang, G., Irani, N., Joshi, A., Kadom, N., Kaplan, S. L., Kolli, K. P., Krishnaraj, A., Marsh, D., Miller, A., Mintz, A., Pahade, J., Policeni, B., Rubio, E. I., Towbin, A. J., Wald, C., Wandtke, B., Willis, M. 2020

    View details for DOI 10.1016/j.jacr.2020.07.009

    View details for PubMedID 32783896

  • Spontaneous Bleeding from Multiple Intercostal Arteries in a Patient with Coarctation of the Aorta. The Annals of thoracic surgery Wightman, S. C., Wang, Y. n., Rohr, A. M., Greene, C. L., Hwang, G. L., Watkins, A. C., Lui, N. S. 2020


    A 59-year-old man with a history of coarctation repair, mechanical aortic valve, and warfarin therapy presented with right flank pain. Computerized tomography (CT) scan showed a large hematoma encircling an intact descending thoracic aorta. CT angiogram demonstrated multiple areas of intercostal artery extravasation. Interventional radiology performed angiography and embolization. His course was complicated by an effusion and hypoxia; but no further bleeding was noted. We hypothesize coarctation association aneurysms and potential vessel wall weakness and as cause of hematoma in our case. We present the first case with history of repaired coarctation with multiple spontaneous intercostal artery aneurysmal rupture.

    View details for DOI 10.1016/j.athoracsur.2019.12.042

    View details for PubMedID 32035043

  • Needs of Referring Providers by Practice Type: Results of a Survey at an Academic Medical Center. AJR. American journal of roentgenology Larson, D. B., Hwang, G. L. 2020


    OBJECTIVE. The purpose of this study was to test a previously-published hypothetical framework of different referring provider needs for primary care, specialty care, and urgent/emergent care practitioners through questions asked in an annual survey at an academic medical center. MATERIALS AND METHODS. Seven questions regarding provider needs were included in an annual online anonymous survey of referring providers. Multiple choice responses were provided. Differences in responses between provider types were assessed using the Mann-Whitney U test RESULTS. The survey was sent to 3,325 providers. 514 responses were received (response rate = 15.5%). 349 responses were included in the analysis, including 81 responses from primary care, 205 responses from specialty care, and 54 responses from urgent or emergency care. Results indicated that 1) urgent care providers need examinations to be performed and interpreted more quickly, 2) specialist providers prefer greater radiologist specialization, 3) urgent care providers order imaging with greater frequency 4) primary care and urgent care providers order a greater breadth of imaging, 5) primary care providers report greater reliance on radiologist interpretations, and 6) all provider types highly value direct interactions with radiologists. All results were statistically significant and matched the previously-established hypotheses. CONCLUSION. These results support the concept that referring providers tend to value different aspects of radiology services differently, according to predictable characteristics. The findings suggest that the concept of value in radiology is highly context-specific and can potentially be evaluated, at least in part, using practice-specific referring provider assessments.

    View details for DOI 10.2214/AJR.19.22738

    View details for PubMedID 32603226

  • Untapped Resources: Attaining Equitable Representation for Women in IR JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Perez, M. G., Fassiotto, M., Altamirano, J., Hwang, G. L., Maldonado, Y., Josephs, S., Sze, D. Y., Kothary, N. 2019; 30 (4): 579–83
  • Untapped Resources: Attaining Equitable Representation for Women in IR. Journal of vascular and interventional radiology : JVIR Perez, M. G., Fassiotto, M., Altamirano, J., Hwang, G. L., Maldonado, Y., Josephs, S., Sze, D. Y., Kothary, N. 2019


    PURPOSE: To investigate the current state of gender diversity among invited coordinators at the Society of Interventional Radiology (SIR) Annual Scientific Meeting and to compare the academic productivity of female interventional radiologists to that of invited male coordinators.MATERIALS AND METHODS: Faculty rosters for the SIR Annual Scientific Meetings from 2015 to 2017 were stratified by gender to quantify female representation among those asked to lead and coordinate podium sessions. To quantify academic productivity and merit, H-index, publications, and authorship by females over a 6-year period (2012-2017) were statistically compared to that of recurring male faculty.RESULTS: From 2015 to 2017, women held 7.1% (9/126), 4.3%, (8/188), and 13.7% (27/197) of the available coordinator positions for podium sessions, with no representation at the plenary sessions, and subject matter expertise was concentrated in economics and education. Academic productivity of the top quartile of published female interventional radiologists was statistically similar to that of the invited male faculty (H-index P= .722; total publications P= .689; and authorship P= .662).CONCLUSIONS: This study found that senior men dominate the SIR Annual Scientific Meeting, with few women leading or coordinating the podium sessions, despite their established academic track record.

    View details for PubMedID 30772166

  • Technical Feasibility and Clinical Effectiveness of Transjugular Intrahepatic Portosystemic Shunt Creation in Pediatric and Adolescent Patients. Journal of vascular and interventional radiology : JVIR Bertino, F., Hawkins, C. M., Shivaram, G., Gill, A. E., Lungren, M. P., Reposar, A., Sze, D. Y., Hwang, G. L., Koo, K., Monroe, E. 2019; 30 (2): 178


    PURPOSE: To examine the technical feasibility and clinical efficacy of transjugular intrahepatic portosystemic shunt (TIPS) creation in children and adolescents.MATERIALS AND METHODS: Retrospective review was performed of 59 patients (mean age 12.6 y [range, 1.5-20 y], mean weight 47.5 kg [range, 11.4-112.2 kg], mean Model for End-stage Liver Disease/Pediatric End-stage Liver Disease score 12.5 [range, 6-33]) who underwent 61 TIPS attempts at 3 tertiary children's hospitals from 2001 to 2017 for acute esophageal or gastroesophageal variceal bleeding, primary and secondary prevention of variceal bleeding, and refractory ascites. Pediatric liver disease etiologies included biliary atresia, cystic fibrosis, and ductal plate anomalies. Technical, hemodynamic, and clinical success and patency rates were reported at 1, 6, 12, and 24 months. Statistical analysis evaluated reasons for clinical failure. Kaplan-Meier analysis measured clinical success, patency, and transplant-free survival.RESULTS: Technical success was 93.4% (57/61) in 59 consecutive patients. Most common TIPS indications were treating and preventing esophageal and gastroesophageal variceal bleeding (57/59; 96.6%). Hemodynamic success was 94% (47/50). Clinical success was 80.7% (45/56). Two-year clinical success for acute variceal bleeding and ascites was 94.1% and 100%, respectively. Overall patency at 1, 6, 12, and 24 months was 98.0%, 97.8%, 94.3%, and 91.3%. Two-year transplant-free survival was 88.8%. Overall and major complication rates were 21.2% (13/61) and 8.2% (5/61), with 3 mortalities. Gradient reduction < 12 mm Hg correlated with clinical success (P < .01).CONCLUSIONS: TIPS creation in pediatric patients is technically feasible and clinically efficacious for treatment and prevention of esophageal and gastroesophageal variceal hemorrhage. High 2-year clinical success, patency, and survival rates should encourage providers to consider portosystemic shunts as a bridge to liver transplantation.

    View details for PubMedID 30717948

  • Reduction of Muscle Contractions during Irreversible Electroporation Therapy Using High-Frequency Bursts of Alternating Polarity Pulses: A Laboratory Investigation in an ExVivo Swine Model. Journal of vascular and interventional radiology : JVIR Sano, M. B., Fan, R. E., Cheng, K., Saenz, Y., Sonn, G. A., Hwang, G. L., Xing, L. 2018; 29 (6): 893


    PURPOSE: To compare the intensity of muscle contractions in irreversible electroporation (IRE) treatments when traditional IRE and high-frequency IRE (H-FIRE) waveforms are used in combination with a single applicator and distal grounding pad (A+GP) configuration.MATERIALS AND METHODS: An exvivo in situ porcine model was used to compare muscle contractions induced by traditional monopolar IRE waveforms vs high-frequency bipolar IRE waveforms. Pulses with voltages between 200 and 5,000 V were investigated, and muscle contractions were recorded by using accelerometers placed on or near the applicators.RESULTS: H-FIRE waveforms reduced the intensity of muscle contractions in comparison with traditional monopolar IRE pulses. A high-energy burst of 2-mus alternating-polarity pulses energized for 200 mus at 4,500 V produced less intense muscle contractions than traditional IRE pulses, which were 25-100 mus in duration at 3,000 V.CONCLUSIONS: H-FIRE appears to be an effective technique to mitigate the muscle contractions associated with traditional IRE pulses. This may enable the use of voltages greater than 3,000 V necessary for the creation of large ablations invivo.

    View details for PubMedID 29628296

  • Highly Articulated Robotic Needle Achieves Distributed Ablation of Liver Tissue. IEEE robotics and automation letters Gerboni, G., Greer, J. D., Laeseke, P. F., Hwang, G. L., Okamura, A. M. 2017; 2 (3): 1367-1374


    Robotic needle steering will improve percutaneous radio-frequency ablation (RFA) in the liver by performing distributed ablations without requiring multiple punctures of the liver capsule, thus enabling the treatment of large or multifocal tumors. However, state-of-the-art asymmetric-tip robotic needle steering systems do not yet achieve clinically relevant curvature. This work presents the design and development of a highly articulated needle that enables distributed RFA in liver tissue under ultrasound (US) image guidance. Our new needle design attains the target curvature required for liver procedures while meeting important clinical requirements, such as the use of fixed diameter needle introducers, presence of a free needle working channel, robustness for repeated insertions, and conductivity for the delivery of RF current for tissue ablation. The new needle tip includes two important design features: A tendon-actuated Nitinol asymmetric flexure joint, which allows for an active amplification of the needle steering force, and a steel back-bevel tip profile, which decreases the risk of needle jamming. The needle's resulting curvature was evaluated in both phantom and ex vivo liver tissues using segmented US images. The average radius of minimum curvature in ex vivo liver tissue was found to be 33.6 mm, the smallest reported to date. Furthermore, RFA in ex vivo porcine liver tissue tests were performed to demonstrate that distributedablation with a single puncture of the liver capsule is possible via robotic needle steering.

    View details for DOI 10.1109/LRA.2017.2668467

    View details for PubMedID 28664186

    View details for PubMedCentralID PMC5484158

  • 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 Pung, L., Ahmad, M., Mueller, K., Rosenberg, J., Stave, C., Hwang, G. L., Shah, R., Kothary, N. 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

  • The Role of Dual-Phase Cone-Beam CT in Predicting Short-Term Response after Transarterial Chemoembolization for Hepatocellular Carcinoma. Journal of vascular and interventional radiology Müller, K., Datta, S., Gehrisch, S., Ahmad, M., Mohammed, M. A., Rosenberg, J., Hwang, G. L., Louie, J. D., Sze, D. Y., Kothary, N. 2017; 28 (2): 238-245


    To identify computational and qualitative features derived from dual-phase cone-beam CT that predict short-term response in patients undergoing transarterial chemoembolization for hepatocellular carcinoma (HCC).This retrospective study included 43 patients with 59 HCCs. Six features were extracted, including intensity of tumor enhancement on both phases and characteristics of the corona on the washout phase. Short-term response was evaluated by modified Response Evaluation Criteria in Solid Tumors on follow-up imaging, and extracted features were correlated to response using univariate and multivariate analyses.Univariate and multivariate analyses did not reveal a correlation between absolute and relative tumor enhancement characteristics on either phase with response (arterial P = .21; washout P = .40; ∆ P = .90). On multivariate analysis of qualitative characteristics, the presence of a diffuse corona was an independent predictor of incomplete response (P = .038) and decreased the odds ratio of objective response by half regardless of tumor size.Computational features extracted from contrast-enhanced dual-phase cone-beam CT are not prognostic of response to transarterial chemoembolization in patients with HCC. HCCs that demonstrate a diffuse, patchy corona have reduced odds of achieving complete response after transarterial chemoembolization and should be considered for additional treatment with an alternative modality.

    View details for DOI 10.1016/j.jvir.2016.09.019

    View details for PubMedID 27914917

  • Survival in Cirrhotic Patients with High MELD Scores: The TIPping Point DIGESTIVE DISEASES AND SCIENCES Hwang, G. L., Sze, D. Y. 2017; 62 (2): 296–98

    View details for PubMedID 27830408

  • Production of Spherical Ablations Using Nonthermal Irreversible Electroporation: A Laboratory Investigation Using a Single Electrode and Grounding Pad. Journal of vascular and interventional radiology Sano, M. B., Fan, R. E., Hwang, G. L., Sonn, G. A., Xing, L. 2016; 27 (9): 1432-1440 e3


    To mathematically model and test ex vivo a modified technique of irreversible electroporation (IRE) to produce large spherical ablations by using a single probe.Computed simulations were performed by using varying voltages, electrode exposure lengths, and tissue types. A vegetable (potato) tissue model was then used to compare ablations created by conventional and high-frequency IRE protocols by using 2 probe configurations: a single probe with two collinear electrodes (2EP) or a single electrode configured with a grounding pad (P+GP). The new P+GP electrode configuration was evaluated in ex vivo liver tissue.The P+GP configuration produced more spherical ablation volumes than the 2EP configuration in computed simulations and tissue models. In prostate tissue, computed simulations predicted ablation volumes at 3,000 V of 1.6 cm(3) for the P+GP configurations, compared with 0.94 cm(3) for the 2EP configuration; in liver tissue, the predicted ablation volumes were 4.7 times larger than those in the prostate. Vegetable model studies verify that the P+GP configuration produces larger and more spherical ablations than those produced by the 2EP. High-frequency IRE treatment of ex vivo liver with the P+GP configuration created a 2.84 × 2.21-cm ablation zone.Computer modeling showed that P+GP configuration for IRE procedures yields ablations that are larger than the 2EP configuration, creating substantial ablation zones with a single electrode placement. When tested in tissue models and an ex vivo liver model, the P+GP configuration created ablation zones that appear to be of clinically relevant size and shape.

    View details for DOI 10.1016/j.jvir.2016.05.032

    View details for PubMedID 27478129

  • Methods for Improving the Curvature of Steerable Needles in Biological Tissue IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING Adebar, T. K., Greer, J. D., Laeseke, P. F., Hwang, G. L., Okamura, A. M. 2016; 63 (6): 1167-1177


    Robotic needle steering systems have the potential to improve percutaneous interventions such as radiofrequency ablation of liver tumors, but steering techniques described to date have not achieved sufficiently small radius of curvature in biological tissue to be relevant to this application. In this study, the impact of tip geometry on steerable needle curvature was examined.Finite-element simulations and experiments with bent-tip needles in ex vivo liver tissue were performed. Motivated by the results of this analysis, a new articulated-tip steerable needle was designed, in which a distal section is actively switched by a robotic system between a straight tip (resulting in a straight path) and a bent tip (resulting in a curved path).Selection of tip length and angle can greatly improve curvature, with radius of curvature below 5 cm in liver tissue possible through judicious selection of these parameters. An articulated-tip mechanism allows the tip length and angle to be increased, while the straight configuration allows the needle tip to still pass through an introducer sheath and rotate inside the body.Validation testing in liver tissue shows that the new articulated-tip steerable needle achieves smaller radius of curvature compared to bent-tip needles described in previous work.Steerable needles with optimized tip parameters, which can generate tight curves in liver tissue, increase the clinical relevance of needle steering to percutaneous interventions.

    View details for DOI 10.1109/TBME.2015.2484262

    View details for Web of Science ID 000377045500009

    View details for PubMedID 26441438

    View details for PubMedCentralID PMC4862936

  • Superselective Chemoembolization of HCC: Comparison of Short-term Safety and Efficacy between Drug-eluting LC Beads, QuadraSpheres, and Conventional Ethiodized Oil Emulsion. Radiology Duan, F., Wang, E. Q., Lam, M. G., Abdelmaksoud, M. H., Louie, J. D., Hwang, G. L., Kothary, N., Kuo, W. T., Hofmann, L. V., Sze, D. Y. 2016; 278 (2): 612-621


    Purpose To study the comparative short-term safety and efficacy of transcatheter arterial chemoembolization (TACE) with drug-eluting LC Beads loaded with doxorubicin (DEBDOX), doxorubicin-eluting QuadraSpheres (hqTACE), and conventional TACE using ethiodized oil for superselective C-arm computed tomography (CT)-guided treatment of hepatocellular carcinoma (HCC) after the onset of drug shortages. Materials and Methods From March 2010 to March 2011, 166 patients with HCC were treated with 232 superselective TACE procedures using C-arm cone-beam CT at one institution. Patients underwent treatment depending on the availability of materials after the onset of drug shortages. Conventional TACE with doxorubicin, cisplatin, and Ethiodol was performed for 159 procedures, DEBDOX TACE was performed for 47, and hqTACE was performed for 26. Toxicity and objective response were compared at 3 months after treatment. Data were stratified for the high-risk population (Child-Pugh class B, performance status 1, bilobar disease, and/or post-resection recurrence) and initial versus repeat treatment. Kruskal-Wallis H test, Mann-Whitney U test, and Fisher exact test were used to compare the groups, with Bonferroni correction where needed. Results Whole liver response rates trended higher for conventional TACE (conventional TACE, 65.4%; DEBDOX, 63.8%; hqTACE, 53.8%) (P = .085). Only minor trends for differences in toxicity were observed between the three groups. Low-risk patients had higher whole liver (P = .001) and treated lesion (P = .007) response rates when treated with conventional TACE, but no significant differences were seen for DEBDOX and hqTACE. Treatment-naive patients also had higher whole liver (P = .012) and treated lesion (P = .056) response rates. No advantages for drug-eluting microspheres were found. Conclusion Within statistical power limitations, overall toxicity and efficacy were equivalent in patients treated with LC Beads, QuadraSpheres, or ethiodized oil emulsions, including in high-risk patients, when performed superselectively with cone-beam C-arm CT guidance. (©) RSNA, 2015.

    View details for DOI 10.1148/radiol.2015141417

    View details for PubMedID 26334787

  • Methyl Methacrylate Mimicking a Retained Guide Wire. Journal of vascular and interventional radiology : JVIR Moradzadeh, N. n., Hwang, G. n., Nair, V. n., Guo, H. H. 2016; 27 (12): 1906

    View details for PubMedID 27886956

  • Percutaneous Cryoablation for Successful Treatment of a Persistent Urine Leak after Robotic-Assisted Partial Nephrectomy. Journal of vascular and interventional radiology Ward, T. J., Ahmed, O., Chung, B. I., Sze, D. Y., Hwang, G. L. 2015; 26 (12): 1867-1870


    Urine leak after nephron-sparing surgery is a difficult and morbid situation that may delay recovery and necessitate additional hospitalization and intervention. The use of cryoablation to treat a 34-year-old woman with persistent urine leak after robotic-assisted partial nephrectomy is described. Surgery was performed to treat ureteral duplication that resulted in recurrent urinary tract infections and back pain. Cryoablation was performed with computed tomography guidance, targeting urine extravasation observed after the administration of intravenous contrast medium. Imaging performed after ablation confirmed resolution of the urine leak; renal function was preserved.

    View details for DOI 10.1016/j.jvir.2015.08.029

    View details for PubMedID 26596181

  • Periprocedural Patient Care RADIOGRAPHICS Kohi, M. P., Fidelman, N., Behr, S., Taylor, A. G., Kolli, K., Conrad, M., Hwang, G., Weinstein, S. 2015; 35 (6): 1766-1778

    View details for DOI 10.1148/rg.2015150038

    View details for PubMedID 26466184

  • Emergent Salvage Direct Intrahepatic Portocaval Shunt Procedure for Acute Variceal Hemorrhage JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Ward, T. J., Techasith, T., Louie, J. D., Hwang, G. L., Hofmann, L. V., Sze, D. Y. 2015; 26 (6): 829-834


    To review the safety and effectiveness of direct intrahepatic portocaval shunt (DIPS) creation with variceal embolization for acute variceal hemorrhage after a failed transjugular intrahepatic portosystemic shunt (TIPS) creation attempt or in patients with prohibitive anatomy.Transjugular intrahepatic portosystemic shunt and DIPS procedures performed for variceal hemorrhage between January 2008 and July 2014 were reviewed. The default procedure was TIPS creation, with DIPS creation reserved for patients with unfavorable anatomy or who had technically unsuccessful TIPS creation. Thirteen patients underwent DIPS creation (mean age, 60 y ± 12; Child-Pugh class A/B/C, 8%/62%/30%; Model for End-stage Liver Disease score, 15 ± 5; range, 8-26) and 117 underwent TIPS creation. Four patients underwent a TIPS attempt and were converted to DIPS creation upon technical failure; 9 were treated primarily with DIPS creation because of preprocedural imaging revealing unfavorable anatomy (intrahepatic portal thrombosis, n = 2; venous distortion from prior hepatic resections, n = 2; severely angulated hepatic veins, n = 5).Direct intrahepatic portocaval shunt creation with variceal embolization (six gastric or esophageal; seven stomal, duodenal, or rectal) was successful in all patients; 11 also had concomitant variceal sclerotherapy. Mean DIPS procedure time was less than 2 hours. There was 1 major procedural complication. During a mean follow-up of 13.0 months ± 15.5, 1 patient developed DIPS thrombosis and recurrent hemorrhage; 1 patient underwent successful transplantation. Two deaths were observed within 30 days, neither associated with recurrent hemorrhage.Direct intrahepatic portocaval shunt creation appears to be a safe, expedient, and effective treatment for patients with acute variceal hemorrhage who are poor anatomic candidates for TIPS creation or who have undergone unsuccessful TIPS creation attempts.

    View details for DOI 10.1016/j.jvir.2015.03.004

    View details for PubMedID 25881512

  • Development of a High-Throughput Molecular Imaging-Based Orthotopic Hepatocellular Carcinoma Model. Cureus Hwang, G. L., van den Bosch, M. A., Kim, Y. I., Katzenberg, R., Willmann, J. K., Paulmurugan, R., Gambhir, S. S., Hofmann, L. 2015; 7 (6)


    We have developed a novel orthotopic rat hepatocellular (HCC) model and have assessed the ability to use bioluminescence imaging (BLI), positron emission tomography (PET), and ultrasound for early tumor detection and monitoring of disease progression.  Briefly, rat HCC cells were stably transfected with click beetle red as a reporter gene for BLI. Tumor cells were injected under direct visualization into the left or middle lobe of the liver in 37 rats. In six animals, serial PET, BLI, and ultrasound imaging were performed at 10-time points in 28 days. The remainder of the animals underwent PET imaging at 14 days. Tumor implantation was successful in 34 of 37 animals (91.9%). In the six animals that underwent serial imaging, tumor formation was first detected with BLI on Day 4 with continued increase through Day 21, and hypermetabolic activity on PET was first noted on Days 14-15 with continued increase through Day 28. PET activity was seen on Day 14 in the 28 other animals that demonstrated tumor development. Anatomic tumor formation was detected with ultrasound at Days 10-12 with continued growth through Day 28. The first metastases were detected by PET after Day 24.        We have successfully developed and validated a novel orthotopic HCC small animal model that permits longitudinal assessment of change in tumor size using molecular imaging techniques. BLI is the most sensitive imaging method for detection of early tumor formation and growth. This model permits high-throughput in vivo evaluation of image-guided therapies.

    View details for DOI 10.7759/cureus.281

    View details for PubMedID 26180705

    View details for PubMedCentralID PMC4494575

  • Classification of Hypervascular Liver Lesions Based on Hepatic Artery and Portal Vein Blood Supply Coefficients Calculated from Triphasic CT Scans JOURNAL OF DIGITAL IMAGING Boas, F. E., Kamaya, A., Do, B., Desser, T. S., Beaulieu, C. F., Vasanawala, S. S., Hwang, G. L., Sze, D. Y. 2015; 28 (2): 213-223


    Perfusion CT of the liver typically involves scanning the liver at least 20 times, resulting in a large radiation dose. We developed and validated a simplified model of tumor blood supply that can be applied to standard triphasic scans and evaluated whether this can be used to distinguish benign and malignant liver lesions. Triphasic CTs of 46 malignant and 32 benign liver lesions were analyzed. For each phase, regions of interest were drawn in the arterially enhancing portion of each lesion, as well as the background liver, aorta, and portal vein. Hepatic artery and portal vein blood supply coefficients for each lesion were then calculated by expressing the enhancement curve of the lesion as a linear combination of the enhancement curves of the aorta and portal vein. Hepatocellular carcinoma (HCC) and hypervascular metastases, on average, both had increased hepatic artery coefficients compared to the background liver. Compared to HCC, benign lesions, on average, had either a greater hepatic artery coefficient (hemangioma) or a greater portal vein coefficient (focal nodular hyperplasia or transient hepatic attenuation difference). Hypervascularity with washout is a key diagnostic criterion for HCC, but it had a sensitivity of 72 % and specificity of 81 % for diagnosing malignancy in our diverse set of liver lesions. The sensitivity for malignancy was increased to 89 % by including enhancing lesions that were hypodense on all phases. The specificity for malignancy was increased to 97 % (p = 0.039) by also examining hepatic artery and portal vein blood supply coefficients, while maintaining a sensitivity of 76 %.

    View details for DOI 10.1007/s10278-014-9725-9

    View details for Web of Science ID 000351242500012

    View details for PubMedID 25183580

  • Optimal imaging surveillance schedules after liver-directed therapy for hepatocellular carcinoma. Journal of vascular and interventional radiology Boas, F. E., Do, B., Louie, J. D., Kothary, N., Hwang, G. L., Kuo, W. T., Hovsepian, D. M., Kantrowitz, M., Sze, D. Y. 2015; 26 (1): 69-73


    To optimize surveillance schedules for the detection of recurrent hepatocellular carcinoma (HCC) after liver-directed therapy.New methods have emerged that allow quantitative analysis and optimization of surveillance schedules for diseases with substantial rates of recurrence such as HCC. These methods were applied to 1,766 consecutive chemoembolization, radioembolization, and radiofrequency ablation procedures performed on 910 patients between 2006 and 2011. Computed tomography or magnetic resonance imaging performed just before repeat therapy was set as the time of "recurrence," which included residual and locally recurrent tumor as well as new liver tumors. Time-to-recurrence distribution was estimated by Kaplan-Meier method. Average diagnostic delay (time between recurrence and detection) was calculated for each proposed surveillance schedule using the time-to-recurrence distribution. An optimized surveillance schedule could then be derived to minimize the average diagnostic delay.Recurrence is 6.5 times more likely in the first year after treatment than in the second. Therefore, screening should be much more frequent in the first year. For eight time points in the first 2 years of follow-up, the optimal schedule is 2, 4, 6, 8, 11, 14, 18, and 24 months. This schedule reduces diagnostic delay compared with published schedules and is cost-effective.The calculated optimal surveillance schedules include shorter-interval follow-up when there is a higher probability of recurrence and longer-interval follow-up when there is a lower probability. Cost can be optimized for a specified acceptable diagnostic delay or diagnostic delay can be optimized within a specified acceptable cost.

    View details for DOI 10.1016/j.jvir.2014.09.013

    View details for PubMedID 25446423

  • Immune correlates of talactoferrin alfa in biopsied tumor of relapsed/refractory metastatic non-small cell lung cancer patients. Immunopharmacology and immunotoxicology Riess, J. W., Bhattacharya, N., Blenman, K. R., Neal, J. W., Hwang, G., Pultar, P., San-Pedro Salcedo, M., Engleman, E., Lee, P. P., Malik, R., Wakelee, H. A. 2014; 36 (2): 182-186


    Talactoferrin alfa (TLF) is a unique recombinant form of human lactoferrin. The hypothesized mechanism of action involves TLF binding to the intestinal endothelium inducing dendritic cell maturation and cytokine release leading to infiltration of tumor with monocytes and T-lymphocytes and inhibition of tumor growth.Based on promising phase II trial results, this correlative study was undertaken to examine immune mechanism of action of TLF in metastatic non-small cell lung cancer (NSCLC) patients.Talactoferrin was administered orally at 1.5 g bid weeks 1-12 with 2 weeks off on a 14-week cycle. Enrolled patients had a pathologic diagnosis of NSCLC previously treated with at least two lines of systemic treatment. Patients had core biopsy of tumor before initiation of talactoferrin and at week 7 on TLF. Flow cytometry and quantitative immunohistochemistry for immune correlates were performed on the biopsied specimens.Four patients with metastatic NSCLC were enrolled. The trial was halted pre-maturely in light of negative phase III trial results. For the two patients who had repeat on-treatment tumor biopsies, a consistent increase in monocytes as a percentage of total immune cells was observed. Otherwise, no clear trend of increase or decrease was observed in any other immune cell parameters compared to matched patient pre-treatment biopsies.Repeat biopsies for immune correlates by flow cytometry and quantitative immunohistochemistry in NSCLC patients are feasible. In the few patients sampled before trial closure, increased monocytes as a total percentage of the immune cell population within tumor was observed in response to TLF.

    View details for DOI 10.3109/08923973.2013.864671

    View details for PubMedID 24494587

  • Real-Time 3D Curved Needle Segmentation Using Combined B-Mode and Power Doppler Ultrasound 17th International Conference on Medical Image Computing and Computer-Assisted Intervention (MICCAI) Greer, J. D., Adebar, T. K., Hwang, G. L., Okamura, A. M. SPRINGER-VERLAG BERLIN. 2014: 381–388


    This paper presents a real-time segmentation method for curved needles in biological tissue based on analysis of B-mode and power Doppler images from a tracked 2D ultrasound transducer. Mechanical vibration induced by an external voice coil results in a Doppler response along the needle shaft, which is centered around the needle section in the ultrasound image. First, B-mode image analysis is performed within regions of interest indicated by the Doppler response to create a segmentation of the needle section in the ultrasound image. Next, each needle section is decomposed into a sequence of points and transformed into a global coordinate system using the tracked transducer pose. Finally, the 3D shape is reconstructed from these points. The results of this method differ from manual segmentation by 0.71 ± 0.55 mm in needle tip location and 0.38 ± 0.27 mm along the needle shaft. This method is also fast, taking 5-10 ms to run on a standard PC, and is particularly advantageous in robotic needle steering, which involves thin, curved needles with poor echogenicity.

    View details for Web of Science ID 000347686400048

  • Applying a Structured Innovation Process to Interventional Radiology: A Single-Center Experience JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Sista, A. K., Hwang, G. L., Hovsepian, D. M., Sze, D. Y., Kuo, W. T., Kothary, N., Louie, J. D., Yamada, K., Hong, R., Dhanani, R., Brinton, T. J., Krummel, T. M., Makower, J., Yock, P. G., Hofmann, L. V. 2012; 23 (4): 488-494


    To determine the feasibility and efficacy of applying an established innovation process to an active academic interventional radiology (IR) practice.The Stanford Biodesign Medical Technology Innovation Process was used as the innovation template. Over a 4-month period, seven IR faculty and four IR fellow physicians recorded observations. These observations were converted into need statements. One particular need relating to gastrostomy tubes was diligently screened and was the subject of a single formal brainstorming session.Investigators collected 82 observations, 34 by faculty and 48 by fellows. The categories that generated the most observations were enteral feeding (n = 9, 11%), biopsy (n = 8, 10%), chest tubes (n = 6, 7%), chemoembolization and radioembolization (n = 6, 7%), and biliary interventions (n = 5, 6%). The output from the screening on the gastrostomy tube need was a specification sheet that served as a guidance document for the subsequent brainstorming session. The brainstorming session produced 10 concepts under three separate categories.This formalized innovation process generated numerous observations and ultimately 10 concepts to potentially to solve a significant clinical need, suggesting that a structured process can help guide an IR practice interested in medical innovation.

    View details for DOI 10.1016/j.jvir.2011.12.029

    View details for Web of Science ID 000302396300009

    View details for PubMedID 22464713

  • Yttrium-90 Radioembolization of Renal Cell Carcinoma Metastatic to the Liver JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Abdelmaksoud, M. H., Louie, J. D., Hwang, G. L., Kothary, N., Minor, D. R., Sze, D. Y. 2012; 23 (3): 323-330


    To investigate the safety and efficacy of yttrium-90 ((90)Y) hepatic radioembolization treatment of patients with liver-dominant metastatic renal cell carcinoma (RCC) refractory to immunotherapy and targeted therapies.Between March 2006 and December 2010, six patients with metastatic RCC underwent eight radioembolization treatments with (90)Y-labeled resin microspheres for unresectable liver-dominant metastases. All six patients had previous hepatic tumor progression despite targeted therapies or immunotherapies. All had bilobar disease and required whole-liver treatment. Clinical and biochemical toxicities were recorded, and tumor response was assessed every 2-3 months after treatment by cross-sectional imaging.The median dose delivered was 1.89 Gbq (range 0.41-2.03 Gbq). Grade 1 and 2 toxicities were noted in all patients, primarily fatigue. Follow-up imaging was available for five patients. In follow-up periods from 2-64 months (mean 25 months), three patients showed complete responses, and 1 patient showed a partial response by standard imaging criteria, and these patients are alive at 64 months, 55 months, 17 months, and 7 months after treatment. Two patients with rapid progression of disease died within 2 months of treatment, although hepatic malignancy or failure was not the cause of death in either patient.(90)Y radioembolization is a promising option for liver-dominant metastatic RCC with potential for providing long-term survival in patients refractory to or intolerant of targeted therapies.

    View details for DOI 10.1016/j.jvir.2011.11.007

    View details for PubMedID 22277275

  • Transarterial Chemoembolization for Hepatocellular Carcinomas in Watershed Segments: Utility of C-Arm Computed Tomography for Treatment Planning JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Abdelmaksoud, M. H., Louie, J. D., Hwang, G. L., Sze, D. Y., Hofmann, L. V., Kothary, N. 2012; 23 (2): 281-283

    View details for DOI 10.1016/j.jvir.2011.11.008

    View details for Web of Science ID 000299656600021

    View details for PubMedID 22264556

  • Percutaneous Cholecystostomy for Acute Cholecystitis: Ten-Year Experience JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Joseph, T., Unver, K., Hwang, G. L., Rosenberg, J., Sze, D. Y., Hashimi, S., Kothary, N., Louie, J. D., Kuo, W. T., Hofmann, L. V., Hovsepian, D. M. 2012; 23 (1): 83-88


    To review the clinical course of patients with acute cholecystitis treated by percutaneous cholecystostomy, and to identify risk factors retrospectively that predict outcome.A total of 106 patients diagnosed with acute cholecystitis were treated by percutaneous cholecystostomy during a 10-year period. Seventy-one (67%) presented to the emergency department (ED) specifically for acute cholecystitis, and 35 (23%) were inpatients previously admitted for other conditions. Outcomes of the two groups were compared with respect to severity of illness, leukocytosis, bile culture, liver function tests, imaging features, time intervals from onset of symptoms to medical and percutaneous intervention, and whether surgical cholecystectomy was later performed.Overall, 72 patients (68%) showed an improvement clinically, whereas 34 (32%) showed no improvement or a clinically worsened condition after cholecystostomy. Patients who presented to the ED primarily with acute cholecystitis fared better (84% of patients showed improvement) than inpatients (34% showed improvement; P < .0001). Gallstones were identified in 54% of patients who presented to the ED, whereas acalculous cholecystitis was more commonly diagnosed in inpatients (54%). Patients with sepsis had worse outcomes overall (P < .0001). Bacterial bile cultures were analyzed in 95% of patients and showed positive results in 52%, with no overall effect on outcome. There was no correlation between the time of onset of symptoms until antibiotic therapy or cholecystostomy in either group. Long-term outcomes for both groups were better for those who later underwent cholecystectomy (P < .0001).Outcomes after percutaneous cholecystostomy for acute cholecystitis are better when the disease is primary and not precipitated by concurrent illness.

    View details for DOI 10.1016/j.jvir.2011.09.030

    View details for PubMedID 22133709

  • Imaging Guidance with C-arm CT: Prospective Evaluation of Its Impact on Patient Radiation Exposure during Transhepatic Arterial Chemoembolization JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Kothary, N., Abdelmaksoud, M. H., Tognolini, A., Fahrig, R., Rosenberg, J., Hovsepian, D. M., Ganguly, A., Louie, J. D., Kuo, W. T., Hwang, G. L., Holzer, A., Sze, D. Y., Hofmann, L. V. 2011; 22 (11): 1535-1544


    To prospectively evaluate the impact of C-arm CT on radiation exposure to hepatocellular carcinoma (HCC) patients treated by chemoembolization.Patients with HCC (N = 87) underwent digital subtraction angiography (DSA; control group) or combined C-arm CT/DSA (test group) for chemoembolization. Dose-area product (DAP) and cumulative dose (CD) were measured for guidance and treatment verification. Contrast agent volume and C-arm CT utility were also measured.The marginal DAP increase in the test group was offset by a substantial (50%) decrease in CD from DSA. Use of C-arm CT allowed reduction of DAP and CD from DSA imaging (P = .007 and P = .017). Experienced operators were more efficient in substituting C-arm CT for DSA, resulting in a negligible increase (7.5%) in total DAP for guidance, compared with an increase of 34% for all operators (P = .03). For treatment verification, DAP from C-arm CT exceeded that from DSA, approaching that of conventional CT. The test group used less contrast medium (P = .001), and C-arm CT provided critical or supplemental information in 20% and 17% of patients, respectively.Routine use of C-arm CT can increase stochastic risk (DAP) but decrease deterministic risk (CD) from DSA. However, the increase in DAP is operator-dependent, thus, with experience, it can be reduced to under 10%. C-arm CT provides information not provided by DSA in 33% of patients, while decreasing the use of iodinated contrast medium. As with all radiation-emitting modalities, C-arm CT should be used judiciously.

    View details for DOI 10.1016/j.jvir.2011.07.008

    View details for PubMedID 21875814

  • In Vitro Design and Characterization of the Nonviral Gene Delivery Vector lopamidol, Protamine, Ethiodized Oil Reagent JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Higgins, L. J., Hwang, G. L., Rosenberg, J., Katzenberg, R. H., Kothary, N., Sze, D. Y., Hofmann, L. V. 2011; 22 (10): 1457-1463


    To demonstrate cellular selectivity toward hepatoma cells and compare the efficiency of gene delivery of a novel nonviral vector of iopamidol, protamine, and ethiodized oil reagents (VIPER).Rat hepatocellular carcinoma (HCC) cells were transfected in triplicate under varying conditions by using firefly luciferase as a reporter gene. Conditions included variations of a protamine:DNA (P:D) complex (20:1, 50:1, 100:1, 200:1 mass ratios), iopamidol (0%, 10%, 33%), and ethiodized oil (0%, 1%, 2%, 4%, 8%, and 16%). The conditions affording efficient gene transfer and ease of translation to in vivo studies were selected for cell line comparison (HCC cells vs hepatocytes). Adenoviral transduction was compared with nonviral vector transfection.At low concentrations, ethiodized oil increased transfection efficiency regardless of P:D mass ratio. However, high concentrations resulted in significant attenuation. Unexpectedly, the addition of iopamidol to P:D complexes markedly improved transfection efficiency. When using an optimal P:D, iopamidol, and ethiodized oil solution, DNA transfection of normal liver and tumor cells showed significant selectivity for tumor cells. In the context of hepatoma cells, transfection efficiency with the nonviral vector was better than 10(4) pfu adenovirus.The development and characterization of the VIPER system provides a possible alternative to viral gene therapy of HCC.

    View details for DOI 10.1016/j.jvir.2011.06.025

    View details for PubMedID 21856173

  • Embolization of Parasitized Extrahepatic Arteries to Reestablish Intrahepatic Arterial Supply to Tumors before Yttrium-90 Radioembolization JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Abdelmaksoud, M. H., Louie, J. D., Kothary, N., Hwang, G. L., Kuo, W. T., Hofmann, L. V., Hovsepian, D. M., Sze, D. Y. 2011; 22 (10): 1355-1362


    To perform embolization of parasitized extrahepatic arteries (EHAs) before radioembolization to reestablish intrahepatic arterial supply to large, peripheral tumors, and to evaluate the technical and clinical outcomes of this intervention.Among 201 patients retrospectively analyzed, embolization of 73 parasitized EHAs in 35 patients was performed. Most embolization procedures were performed during preparatory angiography using large particles and coils. Digital subtraction angiography (DSA), C-arm computed tomography (CT), and technetium-99m macroaggregated albumin ((99m)TcMAA) scintigraphy were used to evaluate the immediate perfusion via intrahepatic collateral channels of target tumor areas previously supplied by parasitized EHAs. Follow-up imaging of differential regional tumor response was used to evaluate microsphere distribution and clinical outcome.After embolization, reestablishment of intrahepatic arterial supply was confirmed by both DSA and C-arm CT in 94% of territories and by scintigraphy in 96%. In 32% of patients, the differential response of treatment could not be evaluated because of uniform disease progression. However, symmetric regional tumor response in 94% of evaluable patients indicated successful delivery of microspheres to the territories previously supplied by parasitized EHAs.Reestablishment of intrahepatic arterial inflow to hepatic tumors by embolization of parasitized EHAs is safe and effective and results in successful delivery of yttrium-90 microspheres to tumors previously perfused by parasitized EHAs.

    View details for DOI 10.1016/j.jvir.2011.06.007

    View details for PubMedID 21961979

  • Consolidation of Hepatic Arterial Inflow by Embolization of Variant Hepatic Arteries in Preparation for Yttrium-90 Radioembolization JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Abdelmaksoud, M. H., Louie, J. D., Kothary, N., Hwang, G. L., Kuo, W. T., Hofmann, L. V., Hovsepian, D. M., Sze, D. Y. 2011; 22 (10): 1364-1372


    Before yttrium-90 ((90)Y) radioembolization administration, the authors consolidated arterial inflow by embolizing variant hepatic arteries (HAs) to make microsphere delivery simpler and safer. The present study reviews the technical and clinical success of these consolidation procedures.Preparatory and treatment angiograms were retrospectively analyzed for 201 patients. Variant HAs were coil-embolized during preparatory angiography to simplify arterial anatomy. Collateral arterial perfusion of territories previously supplied by variant HAs was evaluated by digital subtraction angiography (DSA), C-arm computed tomography (CT), and technetium-99m ((99m)Tc)-macroaggregated albumin (MAA) scintigraphy, and by follow-up evaluation of regional tumor response.A total of 47 variant HAs were embolized in 43 patients. After embolization of variant HAs, cross-perfusion into the embolized territory was depicted by DSA and by C-arm CT in 100% of patients and by (99m)Tc-MAA scintigraphy in 92.7%. Uniform progressive disease prevented evaluation in 33% of patients, but regional tumor response in patients who responded supported successful delivery of microspheres to the embolized territories in 95.5% of evaluable patients.Embolization of variant HAs for consolidation of hepatic supply in preparation for (90)Y radioembolization promotes treatment of affected territories via intrahepatic collateral channels.

    View details for DOI 10.1016/j.jvir.2011.06.014

    View details for PubMedID 21961981

  • Photothermal Ablation with the Excimer Laser Sheath Technique for Embedded Inferior Vena Cava Filter Removal: Initial Results from a Prospective Study JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Kuo, W. T., Odegaard, J. I., Louie, J. D., Sze, D. Y., Unver, K., Kothary, N., Rosenberg, J. K., Hovsepian, D. M., Hwang, G. L., Hofmann, L. V. 2011; 22 (6): 813-823


    To evaluate the safety and effectiveness of the excimer laser sheath technique for removing embedded inferior vena cava (IVC) filters.Over 12 months, 25 consecutive patients undergoing attempted IVC filter retrieval with a laser-assisted sheath technique were prospectively enrolled into an institutional review board-approved study registry. There were 10 men and 15 women (mean age 50 years, range 20-76 years); 18 (72%) of 25 patients were referred from an outside hospital. Indications for retrieval included symptomatic filter-related acute caval thrombosis (with or without acute pulmonary embolism), chronic IVC occlusion, and bowel penetration. Retrieval was also performed to remove risks from prolonged implantation and potentially to eliminate need for lifelong anticoagulation. After failure of standard methods, controlled photothermal ablation of filter-adherent tissue with a Spectranetics laser sheath and CVX-300 laser system was performed. All patients were evaluated with cavography, and specimens were sent for histologic analysis.Laser-assisted retrieval was successful in 24 (96%) of 25 patients as follows: 11 Günther Tulip (mean 375 days, range 127-882 days), 4 Celect (mean 387 days, range 332-440 days), 2 Option (mean 215 days, range 100-330 days), 4 OPTEASE (mean 387 days, range 71-749 days; 1 failed 188 days), 2 TRAPEASE (mean 871 days, range 187-1,555 days), and 2 Greenfield (mean 12.8 years, range 7.2-18.3 years). There was one (4%) major complication (acute thrombus, treated with thrombolysis), three (12%) minor complications (small extravasation, self-limited), and one adverse event (coagulopathic retroperitoneal hemorrhage) at follow-up (mean 126 days, range 13-302 days). Photothermal ablation of filter-adherent tissue was histologically confirmed in 23 (92%) of 25 patients.The laser-assisted sheath technique appears to be a safe and effective tool for retrieving embedded IVC filters, including permanent types, with implantation ranging from months to > 18 years.

    View details for DOI 10.1016/j.jvir.2011.01.459

    View details for PubMedID 21530309

  • Intrahepatic Collateral Supply to the Previously Embolized Right Gastric Artery: A Potential Pitfall for Nontarget Radioembolization JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Meer, A. B., Louie, J. D., Abdelmaksoud, M. H., Kothary, N., Hovsepian, D. M., Hofmann, L. V., Kuo, W. T., Hwang, G. L., Sze, D. Y. 2011; 22 (4): 575-577

    View details for DOI 10.1016/j.jvir.2010.12.031

    View details for Web of Science ID 000289340100024

    View details for PubMedID 21463762

  • Common Iliac Vein Stenosis and Risk of Symptomatic Pulmonary Embolism: An Inverse Correlation JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Chan, K. T., Popat, R. A., Sze, D. Y., Kuo, W. T., Kothary, N., Louie, J. D., Hovsepian, D. M., Hwang, G. L., Hofmann, L. V. 2011; 22 (2): 133-141


    To test the hypothesis that a common iliac vein (CIV) stenosis may impair embolization of a large deep venous thrombosis (DVT) to the lungs, decreasing the incidence of a symptomatic pulmonary embolism (PE).Between January 2002 and August 2007, 75 patients diagnosed with unilateral DVT were included in a single-institution case-control study. Minimum CIV diameters were measured 1 cm below the inferior vena cava (IVC) bifurcation on computed tomography (CT) images. A significant stenosis in the CIV ipsilateral to the DVT was defined as having either a diameter 4 mm or less or a greater than 70% reduction in lumen diameter. A symptomatic PE was defined as having symptoms and imaging findings consistent with a PE. The odds of symptomatic PE versus CIV stenosis were assessed using logistic regression models. The associations between thrombus location, stenosis, and symptomatic PE were assessed using a stratified analysis.Of 75 subjects, 49 (65%) presented with symptomatic PE. There were 17 (23%) subjects with a venous lumen 4 mm or less and 12 (16%) subjects with a greater than 70% stenosis. CIV stenosis of 4 mm or less resulted in a decreased odds of a symptomatic PE compared with a lumen greater than 4 mm (odds ratio [OR] 0.17, P = .011), whereas a greater than 70% stenosis increased the odds of DVT involving the CIV (OR 7.1, P = .047).Among patients with unilateral DVT, those with an ipsilateral CIV lumen of 4 mm or less have an 83% lower risk of developing symptomatic PE compared with patients with a CIV lumen greater than 4 mm.

    View details for DOI 10.1016/j.jvir.2010.10.009

    View details for PubMedID 21276911

  • C-arm Computed Tomography for Hepatic Interventions: A Practical Guide JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Tognolini, A., Louie, J., Hwang, G., Hofmann, L., Sze, D., Kothary, N. 2010; 21 (12): 1817-1823


    With adoption of catheter-based techniques that require technically difficult catheterization, the need for imaging platforms that exploit the advantages of multiple modalities and offer three-dimensional visualization has correspondingly increased. At the authors' institution, C-arm computed tomography (CT) is routinely used to complement conventional digital subtraction angiography for transcatheter therapy. The goal of the present report is to share experience with the use of C-arm CT in hepatic interventions, with the aim to provide practical tips for optimizing image acquisition and postprocessing. Although the authors' direct experience is limited to the equipment of a single manufacturer, many of the principles and guidelines can be readily extrapolated to other C-arm CT systems.

    View details for DOI 10.1016/j.jvir.2010.07.027

    View details for PubMedID 20970354

  • Renewing Focus on Resident Education: Increased Responsibility and Ownership in Interventional Radiology Rotations Improves the Educational Experience JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Kothary, N., Ghatan, C. E., Hwang, G. L., Kuo, W. T., Louie, J. D., Sze, D. Y., Hovsepian, D. M., Desser, T. S., Hofmann, L. V. 2010; 21 (11): 1697-1702


    To enhance the educational experience among residents rotating through interventional radiology (IR) by encouraging ownership and responsibility.In May 2006, the authors implemented changes in resident education in IR that included increased clinical responsibilities, structured didactics, and greater hands-on experience, including call. Residents were assigned as first assistants, ownership of cases was encouraged, and assignment to a week on the consult service was instituted to help residents better understand all aspects of IR practice. Additional faculty recruitment and program expansion ensured the same high level of training for the fellowship program. Evaluations were reviewed every year (July 1, 2007-June 30, 2009) for hands-on training, daily teaching, didactic conferences, and overall effectiveness of the clinical service. A graduated scale of 1-5 was used.In 2009, 3 years after the curricular changes were made, the quality of hands-on training, daily case reviews and consults, didactics, and overall education had markedly improved with 89%, 71%, 65%, and 82% of the residents rating these respective aspects of the training as "above expectations" (4 on a scale of 5) or "superior" (5 on a scale of 5) compared with 77%, 23%, 20%, and 60% in 2005-2006. Three years after the changes, the impact of these changes on recruitment patterns also showed improvement, with 28.6% of the class of 2010 pursuing a fellowship in IR.Increasing resident ownership, responsibility, and hands-on experience improves resident education in IR, which, in turn, promotes interest in the field.

    View details for DOI 10.1016/j.jvir.2010.07.009

    View details for PubMedID 20884234

  • Development of New Hepaticoenteric Collateral Pathways after Hepatic Arterial Skeletonization in Preparation for Yttrium-90 Radioembolization JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Abdelmaksoud, M. H., Hwang, G. L., Louie, J. D., Kothary, N., Hofmann, L. V., Kuo, W. T., Hovsepian, D. M., Sze, D. Y. 2010; 21 (9): 1385-1395


    Development of new hepaticoenteric anastomotic vessels may occur after endovascular skeletonization of the hepatic artery. Left untreated, they can serve as pathways for nontarget radioembolization. The authors reviewed the incidence, anatomy, management, and significance of collateral vessel formation in patients undergoing radioembolization.One hundred thirty-eight treatments performed on 122 patients were reviewed. Each patient underwent a preparatory digital subtraction angiogram (DSA) and embolization of all hepaticoenteric vessels in preparation for yttrium-90 ((90)Y) administration. Successful skeletonization was verified by C-arm computed tomography (CACT) and technetium-99m macroaggregated albumin ((99m)TcMAA) scintigraphy. During the subsequent treatment session, DSA and CACT were repeated before administration of (90)Y, and the detection of extrahepatic perfusion prompted additional embolization.Forty-two patients (34.4%) undergoing 43 treatments (31.2%) required adjunctive embolization of hepaticoenteric vessels immediately before (90)Y administration. Previous scintigraphy findings showed extrahepatic perfusion in only three cases (7.1%). Vessels were identified by DSA in 54.1%, by CACT in 4.9%, or required both in 41.0%. The time interval between angiograms did not correlate with risk of requiring reembolization (P = .297). A total of 19.7% of vessels were new collateral vessels not visible during the initial angiography. Despite reembolization, three patients (7.1%) had gastric or duodenal ulceration, compared with 1.3% who never had visible collateral vessels, all of whom underwent whole-liver treatment with resin microspheres (P = .038).Development of collateral hepaticoenteric anastomoses occurs after endovascular skeletonization of the hepatic artery. Identified vessels may be managed by adjunctive embolization, but patients appear to remain at increased risk for gastrointestinal complications.

    View details for DOI 10.1016/j.jvir.2010.04.030

    View details for PubMedID 20688531

  • Computed Tomography-Guided Percutaneous Needle Biopsy of Indeterminate Pulmonary Pathology: Efficacy of Obtaining a Diagnostic Sample in Immunocompetent and Immunocompromised Patients CLINICAL LUNG CANCER Kothary, N., Bartos, J. A., Hwang, G. L., Dua, R., Kuo, W. T., Hofmann, L. V. 2010; 11 (4): 251-256


    We aimed to evaluate the efficacy of computed tomography (CT)-guided percutaneous lung biopsy of pulmonary nodules with indeterminate radiologic characteristics in patients at risk for malignant and nonmalignant processes such as infection or inflammation.From January 2003 to September 2008, 262 patients (mean age, 59 years; range, 18-92 years) with pulmonary nodules or a mass of uncertain etiology and with indeterminate radiologic characteristics underwent CT-guided percutaneous lung biopsy. Patients with discordant clinical history and imaging findings or immunocompromised patients at risk for both etiologies were included. Specimens were submitted for both cytology and microbiology.Of the entire cohort, 166 patients (63.4%) had a nonmalignant process, and 96 patients (36.6%) had a malignancy. CT-guided percutaneous lung biopsy established a diagnosis in 166 patients (63.4%). Of the 166 patients with a nonmalignant etiology and 96 patients with malignancy, it provided a definitive diagnosis in 91 patients (54.8%) and 75 patients (78.1%), respectively, a difference that was statistically significant (P = .0001). Overall diagnostic efficacy between immunocompetent and immunocompromised patients was comparable (P = .2); however, detection of infection or inflammation in individual groups was lower compared with detection of malignancy (P = .002 and P = .06, respectively).CT-guided percutaneous lung biopsy in patients who are clinically at risk for both nonmalignant and malignant processes continues to be a challenge. Although CT-guided percutaneous biopsy can establish an accurate diagnosis in a large majority of patients with malignancy, it is significantly less sensitive for infectious or inflammatory processes.

    View details for DOI 10.3816/CLC.2010.n.032

    View details for PubMedID 20630827

  • Utility of C-arm CT in Patients with Hepatocellular Carcinoma undergoing Transhepatic Arterial Chemoembolization JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Tognolini, A., Louie, J. D., Hwang, G. L., Hofmann, L. V., Sze, D. Y., Kothary, N. 2010; 21 (3): 339-347


    To evaluate the utility of C-arm computed tomography (CT) on treatment algorithms in patients undergoing transhepatic arterial chemoembolization for hepatocellular carcinoma (HCC).From March 2008 to July 2008, 84 consecutive patients with HCC underwent 100 consecutive transhepatic arterial chemoembolizations with iodized oil. Unenhanced and iodinated contrast medium-enhanced C-arm CT with planar and three-dimensional imaging were performed in addition to conventional digital subtraction angiography (DSA) in all patients. The effect on diagnosis and treatment was determined by testing the hypotheses that C-arm CT, in comparison to DSA, provides (a) improved lesion detection, (b) expedient identification and mapping of arterial supply to a tumor, (c) improved characterization of a lesion to allow confident differentiation of HCC from pseudolesions such as arterioportal shunts, and (d) an improved evaluation of treatment completeness. The effect of C-arm CT was analyzed on the basis of information provided with C-arm CT that was not provided or readily apparent at DSA.C-arm CT was technically successful in 93 of the 100 procedures (93%). C-arm CT provided information not apparent or discernible at DSA in 30 of the 84 patients (36%) and resulted in a change in diagnosis, treatment planning, or treatment delivery in 24 (28%). The additional information included, amongst others, visualization of additional or angiographically occult tumors in 13 of the 84 patients (15%) and identification of incomplete treatment in six (7.1%).C-arm CT is a useful collaborative tool in patients undergoing transhepatic arterial chemoembolization and can affect patient care in more than one-fourth of patients.

    View details for DOI 10.1016/j.jvir.2009.11.007

    View details for PubMedID 20133156

  • High-risk Retrieval of Adherent and Chronically Implanted IVC Filters: Techniques for Removal and Management of Thrombotic Complications 34th Annual Conference of the Society-of-Interventional-Radiology Kuo, W. T., Tong, R. T., Hwang, G. L., Louie, J. D., Lebowitz, E. A., Sze, D. Y., Hofmann, L. V. ELSEVIER SCIENCE INC. 2009: 1548–56


    To evaluate the safety and efficacy of aggressive techniques for retrieving adherent and chronically implanted inferior vena cava (IVC) filters.A single-center retrospective review was performed on all patients who underwent attempted filter retrieval from October 2007 through October 2008. Patients were included in the study if they had an adherent filter, refractory to standard retrieval techniques, and underwent high-risk retrieval after procedural risks were deemed lower than risks of long-term filter implantation.Fourteen patients were diagnosed with an adherent filter, 13 (93%) of whom were candidates for high-risk retrieval. These patients included seven men and six women (mean age, 40 years; age range, 18-71 years). Nine of the 13 patients (69%) were referred from an outside hospital. Filter retrieval was performed for the following indications: to avoid the risk of long-term thrombotic complications in a young patient (n= 6), to treat symptomatic filter-related IVC stenosis (n= 5), to treat symptomatic filter penetration (n= 1), and to avoid the need for lifelong anticoagulation (n= 1). There were eight Günther-Tulip filters (mean dwell time, 356 days; range 53-1,181 days), two Optease filters (mean dwell time, 62 days; range, 52-72 days), one G2 filter (dwell time, 420 days), and two Recovery filters (mean dwell time, 1,630 days; range, 1,429-1,830 days). Three IVC occlusions necessitated recanalization to facilitate retrieval. High-risk retrieval with use of various techniques with aggressive force was successful in all 13 patients (100%). Partial caval thrombosis occurred in the first four patients (31%) but did not occur after procedural modifications were implemented. There were no complications at clinical follow-up (mean, 221 days; range, 84-452 days).Alternative techniques can be used to retrieve adherent IVC filters implanted for up to 3-5 years. Although caval thrombosis was an observed complication, protocol modifications appeared to reduce this risk.

    View details for DOI 10.1016/j.jvir.2009.08.024

    View details for PubMedID 19864160

  • Incorporating Cone-beam CT into the Treatment Planning for Yttrium-90 Radioembolization JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Louie, J. D., Kothary, N., Kuo, W. T., Hwang, G. L., Hofmann, L. V., Goris, M. L., Iagaru, A. H., Sze, D. Y. 2009; 20 (5): 606-613


    To prepare for yttrium-90 ((90)Y) microsphere radioembolization therapy, digital subtraction angiography (DSA) and technetium- 99m-labeled macroaggregated albumin ((99m)Tc MAA) scintigraphy are used for treatment planning and detection of potential nontarget embolization. The present study was performed to determine if cone-beam computed tomography (CBCT) affects treatment planning as an adjunct to these conventional imaging modalities.From March 2007 to August 2008, 42 consecutive patients (21 men, 21 women; mean age, 59 years; range, 21-75 y) who underwent radioembolization were evaluated by CBCT in addition to DSA and (99m)Tc MAA scintigraphy during treatment planning, and their records were retrospectively reviewed. The contrast-enhanced territories shown by CBCT with selective intraarterial contrast agent administration were used to predict intrahepatic and possible extrahepatic distribution of microspheres.In 22 of 42 cases (52%), extrahepatic enhancement or incomplete tumor perfusion seen on CBCT affected the treatment plan. In 14 patients (33%), the findings were evident exclusively on CBCT and not detected by DSA. When comparing CBCT versus (99m)Tc MAA scintigraphy, CBCT showed eight cases of extrahepatic enhancement (19%) that were not evident on (99m)Tc MAA imaging. CBCT findings directed the additional embolization of vessels or repositioning of the catheter for better contrast agent and microsphere distribution. One case of gastric ulcer from nontarget embolization caused by reader error was observed.CBCT can provide additional information about tumor and tissue perfusion not currently detectable by DSA or (99m)Tc MAA imaging, which should optimize (90)Y microsphere delivery and reduce nontarget embolization.

    View details for DOI 10.1016/j.jvir.2009.01.021

    View details for PubMedID 19345589

  • Bidirectionally Adjustable TIPS Reduction by Parallel Stent and Stent-Graft Deployment JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Sze, D. Y., Hwang, G. L., Kao, J. S., Frisoli, J. K., Kee, S. T., Razavi, M. K., Ahmed, A. 2008; 19 (11): 1653-1658


    Excessive shunting through transjugular intrahepatic portosystemic shunts (TIPS) can cause life-threatening hepatic encephalopathy and insufficiency. Intentional reduction of flow may be effective but difficult to control. The present report describes refinements of the parallel stent/stent-graft technique of flow reduction that is adjustable in either direction. Six patients underwent TIPS reduction with varying stent positioning and a variety of commercial products. Flow was adjusted by iterative balloon dilatation of the stent and stent-graft, resulting in a mean gradient increase of 8 mm Hg. All cases were technically successful, but 1-year survival was seen in only the patient who underwent liver transplantation.

    View details for DOI 10.1016/j.jvir.2008.08.011

    View details for Web of Science ID 000260694700018

    View details for PubMedID 18823797

  • Role of image-guided vascular intervention in therapeutic angiogenesis translational research. Expert review of cardiovascular therapy Hwang, G. L., Patel, T. H., Hofmann, L. V. 2007; 5 (5): 903-915


    Therapeutic angiogenesis, the process of growing collateral blood vessels to better perfuse ischemic tissue, has been hailed as an up-and-coming treatment for symptomatic lower-extremity peripheral arterial occlusive disease. A minimally invasive durable treatment would be welcome since current treatment options for this disease carry high risk, limited efficacy or limited durability. Unfortunately, as evidenced by disappointing results in multiple clinical trials, therapeutic angiogenesis has yet to deliver in humans the success it has seen in animal models. In this review, we discuss the challenges of translating therapeutic angiogenesis into effective clinical treatments for lower-extremity peripheral arterial occlusive disease and we highlight the role that experts in image-guided vascular interventions can play in advancing the field.

    View details for PubMedID 17867920

  • Recurrent lymphoma of the lung - Computed tomography appearance JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Hwang, G. L., Leung, A. N., Zinck, S. E., Berry, G. J. 2005; 29 (2): 228-230


    To describe the computed tomography findings of recurrent lymphoma involving the lung.Computed tomography scans of 15 patients with biopsy-proven recurrent lymphoma involving the lung were reviewed. Group mean age of enrolled patients was 38 years (range: 14-68 years). Pathologic specimens were obtained by thoracoscopic or open wedge biopsy (n = 8), transbronchial biopsy (n = 5), and fine needle aspiration (n = 2).Nodules, the most common manifestation, were present in all patients; nodules were greater than 10 in number in 12 (80%) of 15 cases and predominantly 6-10 mm in size in 8 cases (53%). Nodular distribution was bilateral and multilobar except in 2 patients, in whom a solitary pulmonary nodule was found. Lymphadenopathy was the second most common finding; it was seen in 13 (87%) of 15 cases and involved an average of 5 nodal stations.Recurrent lymphoma in the lung most commonly manifests as multiple pulmonary nodules that are typically bilateral and multilobar in distribution.

    View details for Web of Science ID 000228030400014

    View details for PubMedID 15772542

  • Abdominal myomectomy versus uterine fibroid embolization in the treatment of symptomatic uterine leiomyomas AMERICAN JOURNAL OF ROENTGENOLOGY Razavi, M. K., Hwang, G., Jahed, A., Modanloo, S., Chen, B. 2003; 180 (6): 1571-1575


    The purpose of this study was to compare treatment efficacy and complications of abdominal myomectomy with those of uterine fibroid embolization in women with symptomatic uterine fibroids.We analyzed the outcomes of 111 consecutive patients who underwent abdominal myomectomy (n = 44) or fibroid embolization (n = 67) over a 30-month period. The mean ages of the two groups were 37.7 years (range, 28-48 years) and 44.2 years (range, 31-56 years), respectively. A questionnaire and review of medical records assessed all procedure-related complications and changes in symptoms. Length of hospital stay, time until resumption of daily activities, and pain medication requirements after the procedure were also analyzed.Follow-up times for the myomectomy and embolization groups were 14.6 and 14.3 months, respectively. The respective observed success rates in abdominal myomectomy and uterine fibroid embolization patients were 64% versus 92% for menorrhagia (p < 0.05), 54% versus 74% for pain (not significant), and 91% versus 76% for mass effect (p < 0.05). The complication rates were 25% (abdominal myomectomy) and 11% (uterine fibroid embolization) (p < 0.05). The respective secondary end points for the two procedures were 2.9 versus 0 days mean hospital stay, 8.7 versus 5.1 days of narcotics use, and 36 versus 8 days until resumption of normal activities. These differences were all statistically significant.Uterine fibroid embolization is a less invasive and safer treatment option in women with symptomatic leiomyomas than myomectomy. Menorrhagia may be better controlled with embolization, and myomectomy may be a better option in patients with mass effect. Both procedures were equally effective in controlling pain.

    View details for Web of Science ID 000183149200013

    View details for PubMedID 12760922

  • Chronic expanding hematoma of the thorax AMERICAN JOURNAL OF ROENTGENOLOGY Hwang, G. L., Moffatt, S. D., Mitchell, J. D., Leung, A. N. 2003; 180 (4): 1182-1183

    View details for Web of Science ID 000181745500064

    View details for PubMedID 12646486

  • Angiographic classification of ovarian artery-to-uterine artery anastomoses: Initial observations in uterine fibroid embolization RADIOLOGY Razavi, M. K., Wolanske, K. A., Hwang, G. L., Sze, D. Y., Kee, S. T., Dake, M. D. 2002; 224 (3): 707-712


    To prospectively study and classify the anastomoses between the ovarian and uterine arteries in women undergoing uterine fibroid embolization, and to compare the presence of such with procedural failures and premature menopause.Angiographic ovarian artery-to-uterine artery anastomoses were studied in 76 consecutive patients undergoing uterine fibroid embolization. Mean patient age was 44.7 years (range, 29-56 years). Clinical follow-up consisted of a standard questionnaire. Procedural failure and complications were compared with the presence of various types of ovarian artery-to-uterine artery connections.Three types of anastomoses were identified. In type I (33 [21.7%] of 152 arteries), flow from the ovarian artery to the uterus was through anastomoses with the main uterine artery. In type II (six arteries [3.9%]), the ovarian artery supplied the fibroids directly. In type III (10 arteries [6.6%]), the major blood supply to the ovary was from the uterine artery. Seven patients (9%) were considered to have clinical failure, with three of the six women with type II anastomoses being in this group. Three of the five women who experienced menopause after fibroid embolization had bilateral ovarian artery-to-uterine artery anastomoses that were classified as high risk.Delineation of ovarian artery-to-uterine artery anastomosis is of practical relevance in avoiding nontarget ovarian embolization, in identification of those who would be at risk of uterine artery embolization or ovarian failure, and in those in whom the ovarian artery can be embolized safely.

    View details for DOI 10.1148/radiol.2243011513

    View details for Web of Science ID 000177621700013

    View details for PubMedID 12202703