Clinical Focus

  • Interventional Radiology
  • Actue Deep Venous Thrombosis
  • Chronic Deep Venous Thrombosis
  • Leg swelling
  • Interventional Oncology
  • Endovascular Procedures
  • Peripheral Arterial Disease
  • Diagnostic Radiology

Academic Appointments

Administrative Appointments

  • Chief, Interventional Radiology, Stanford University School of Medicine (2006 - Present)
  • Medical Director, Digital Health Care Integration, Stanford Healthcare (2018 - Present)
  • Co-Medical Director; Cardiac and Interventional Radiology (Cath Angio), Stanford Hospital and Clinics (2006 - Present)
  • Co-Founder, Grand Rounds, Inc (2012 - Present)

Honors & Awards

  • ARRS/AUR/RSNA Award, Introduction to Research Program (1997)
  • Certificate of Merit, Radiological Society of North America Annual Meeting (1997)
  • Certificate of Merit, Radiological Society of North America Meeting (1998)
  • Cum Laude Award, Radiological Society of North America Annual Meeting (1999)
  • Featured Abstract(top 5%), In vivo Intravascular MR Imaging: Transvenous Technique for Arterial Wall Imaging. SIR Annual Mtg (2003)
  • 3rd Place in Best Oral Presentation, International Society for Magnetic Resonance in Medicine (2003)
  • Finalist, Melvin Judkins Young Investigator Award – American Heart Association (co author) (2004)
  • Resident Research Award, Department of Radiology, The Johns Hopkins Medical Institutions (Mentored: Robert P. Liddell) (2004)
  • Finalist, Melvin Judkins Young Investigator Award – American Heart Association (co author) (2005)
  • Scholarship, The American Roentgen Ray Society Annual Scholarship (2005)
  • Featured Abstract Featured Abstract top 5%), Hypoxia-Inducible Factor-1 for Therapeutic Angiogenesis. SIR Annual Meeting. New Orleans, LA (2005)
  • Travel Award for Resident and Fellows, SIR Annual Mtg. Mentor for Tarak Patel (2005)
  • Scholars Award, Stanford University Medical Scholars-Mentor for Luke Higgins, PhD (2007)
  • Medical Research Grant, Society of Interventional Radiology Foundation-Mentor for Luke Higgins, PhD (2007)
  • Top 5 Best Poster Award, American College of Chest Physicians Annual Mtg. (2007)
  • Fellow/Resident Research Award, Radiological Society of North America/American Roentgen Ray Society-Mentor for Gloria Hwang, MD (2008)
  • Resident/Fellow Research Award, Society of Interventional Radiology Foundation-Mentor for Maurice Van den Bosch (2008)
  • Award, Stanford University Medical Scholars-Mentor for Keith Chan (2008)
  • Resident Research Award, Cardiovascular and Interventional Radiological Society of Europe (2009)
  • Scholars Award, Stanford University Medical Scholars-Mentor for Stephanie Carr (2009)
  • Dr. Constantin Cope Medical Student Award, Society of IR Annual Scientific Mtg-Mentor for Stephanie Carr (2010)
  • Early Career Achievement Award, The Ohio State University School of Medicine (First ever recipient) (2010)
  • The Gary Becker Young Investigator Award, The Society of IR-Mentor for William T. Kuo, MD (2011)
  • Fellow of the Society, The Society of Interventional Radiology (2011)
  • Dr. Constantin Cope Medical Student Award, Society of IR Annual Scientific Mtg-Mentor for Keith Chan (2011)

Professional Education

  • Residency:Johns Hopkins University Dept of Radiology (1999) MD
  • Fellowship:Stanford University Radiology Fellowships (2000) CA
  • Medical Education:Ohio State University College of Medicine Registrar (1995) OH
  • Board Certification: Diagnostic Radiology, American Board of Radiology (1999)
  • B.S., University of Illinois, Biology (1991)
  • M.D., The Ohio State University, Medicine (1995)
  • Residency, The Johns Hopkins Hospital, Radiology (1999)
  • Fellowship, Stanford University Medical Ctr., Interventional Radiology (2000)

Research & Scholarship

Clinical Trials

  • Combination SBRT With TACE for Unresectable Hepatocellular Carcinoma Not Recruiting

    To determine the efficacy and toxicity of TACE combined with SBRT

    Stanford is currently not accepting patients for this trial. For more information, please contact Laurie Ann Columbo, 650-736-0792.

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  • 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 treated with HepaSphere/QuadraSphere compared to conventional transarterial chemoembolization with particle PVA.

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

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  • 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.

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  • 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.

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  • Permission to Collect Blood Over Time for Research Not Recruiting

    To determine whether biomarkers assessed in blood samples can be used to detect individuals at risk for developing blood clots or worsening of their underlying disease. The ultimate goal of the study is to identify key biomarkers derived from blood that are most characteristic and informative of individuals who will go on to develop a clotting complication.

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

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  • Pulmonary Interstitial Lymphography in Early Stage Lung Cancer Not Recruiting

    The stereotactic body radiation therapy (SBRT) procedure is an emerging alternative to the standard treatment for early stage non-small cell lung cancer (NSCLC), typically lobectomy with lymphadenectomy. This procedure (lobectomy) does not fulfill the medical need as many patients are poor operative candidates or decline surgery. This study assesses the feasibility of stereotactic body radiation therapy (SBRT) as a tool to produce therapeutically useful computed tomography (CT) scans, using standard water-soluble iodinated compounds as the contrast agents.

    Stanford is currently not accepting patients for this trial. For more information, please contact Laura Gable, (650) 736 - 0798.

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  • 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.

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  • To Evaluate the Safety and Efficacy for GORE TAG Thoracic Endoprosthesis in the Treatment of Thoracic Aortic Disease Not Recruiting

    PURPOSE OF RESEARCH: Endovascular stent-graft repair of aortic pathologies is a minimally-invasive alternative to open surgery that may decrease morbidity and mortality, particularly in high risk patients. Optimal patient selection, based on pathology and anatomy, is being defined. Technically successful implantation requires adequate assessment of pathology and anatomy, and development and execution of novel and delicate procedures that resolve the pathology while minimizing morbidity and mortality.

    Stanford is currently not accepting patients for this trial. For more information, please contact Archana Verma, (650) 736 - 0959.

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2019-20 Courses


All Publications

  • 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

  • Potent, tumor-specific gene expression in an orthotopic hepatoma rat model using a Survivin-targeted, amplifiable adenoviral vector GENE THERAPY Ahn, B., Ronald, J. A., Kim, Y. I., Katzenberg, R., Singh, A., Paulmurugan, R., Ray, S., Hofmann, L. V., Gambhir, S. S. 2011; 18 (6): 606-612


    Ideal cancer gene therapies should have high tumor specificity and efficacy, and allow systemic administration to target metastases. We recently developed a bi-directional, two-step transcriptional amplification (TSTA) system driven by the tumor-specific Survivin promoter (pSurv) to amplify the correlated expression of both the reporter gene firefly luciferase (FL) and therapeutic gene tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Here, we compare the specificity and potency of an adenovirus carrying this system (Ad-pSurv-TSTA-TRAIL-FL) to a nonspecific vector (Ad-pCMV-FL) in an orthotopic hepatocellular carcinoma (HCC) rat model after systemic administration. At 24 h after injection of Ad-pCMV-FL, bioluminescence imaging revealed a trend (P=0.30) towards greater FL expression in liver versus tumor. In striking contrast, Ad-pSurv-TSTA-TRAIL-FL showed increased FL activity within the tumor compared with the liver (P<0.01), a strong trend towards reduced liver expression compared with Ad-pCMV-FL (P=0.07), and importantly, similar FL levels within tumor compared with Ad-pCMV-FL (P=0.32). Hence, this vector shows potent, tumor-specific transgene expression even after extensive liver transduction and may be of significant value in avoiding hepatotoxicity in HCC patients. Future studies will explore the benefits of tumor-specific TRAIL expression in this model, the potential to target metastases and the extension of this vector for the treatment of other Survivin-positive tumors is warranted.

    View details for DOI 10.1038/gt.2011.5

    View details for Web of Science ID 000291438900010

    View details for PubMedID 21307888

    View details for PubMedCentralID PMC4154811

  • 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

  • MicroRNA-regulated non-viral vectors with improved tumor specificity in an orthotopic rat model of hepatocellular carcinoma GENE THERAPY Ronald, J. A., Katzenberg, R., Nielsen, C. H., Jae, H. J., Hofmann, L. V., Gambhir, S. S. 2013; 20 (10): 1006-1013


    In hepatocellular carcinoma (HCC), tumor specificity of gene therapy is of utmost importance to preserve liver function. MicroRNAs (miRNAs) are powerful negative regulators of gene expression and many are downregulated in human HCC. We identified seven miRNAs that are also downregulated in tumors in a rat hepatoma model (P<0.05) and attempted to improve tumor specificity by constructing a panel of luciferase-expressing vectors containing binding sites for these miRNAs. Attenuation of luciferase expression by the corresponding miRNAs was confirmed across various cell lines and in mouse liver. We then tested our vectors in tumor-bearing rats and identified two miRNAs, miR-26a and miR-122, that significantly decreased expression in liver compared with the control vector (6.40 and 0.26%, respectively; P<0.05). In tumor, miR-122 had a nonsignificant trend towards decreased (∼50%) expression, whereas miR-26 had no significant effect on tumor expression. To our knowledge, this is the first work using differentially expressed miRNAs to de-target transgene expression in an orthotopic hepatoma model and to identify miR-26a, in addition to miR-122, for de-targeting liver. Considering the heterogeneity of miRNA expression in human HCC, this information will be important in guiding development of more personalized vectors for the treatment of this devastating disease.Gene Therapy advance online publication, 30 May 2013; doi:10.1038/gt.2013.24.

    View details for DOI 10.1038/gt.2013.24

    View details for Web of Science ID 000325633500006

    View details for PubMedID 23719066

  • Complex retrieval of fractured, embedded, and penetrating inferior vena cava filters: a prospective study with histologic and electron microscopic analysis. Journal of vascular and interventional radiology Kuo, W. T., Robertson, S. W., Odegaard, J. I., Hofmann, L. V. 2013; 24 (5): 622-630 e1


    To evaluate clinical outcomes, characterize adherent tissue, and analyze inferior vena cava (IVC) filter fractures in patients undergoing complex retrieval for management of filter-related complications. To elucidate mechanisms of filter fracture by radiographic and electron microscopic (EM) evaluation.Over 2.5 years, 50 consecutive patients with fractured and/or penetrating filter components were prospectively enrolled into a single-center study. There were 19 men and 31 women (mean age, 42 y; range, 15-73 y). All patients underwent complex filter retrieval after failure of standard methods, and retrieval indications along with resultant clinical outcomes were evaluated. Specimens with adherent tissue underwent histologic analysis, and all fractured components were studied with EM.Retrieval was successful in all 50 cases (mean implantation, 815 d; range, 20-2,599 d) among the following filters: G2X (n = 23),G2 (n = 9), Eclipse (n = 3), Recovery (n = 4), ALN (n = 1), Celect (n = 7), OptEase (n = 2), and Simon Nitinol (n = 1). Mean indwell time in fractured filters (n = 31) was 1,082 days, versus 408 days in nonfractured filters (n = 19; P = .00169). Neointimal hyperplasia/fibrosis was seen in 46 of 48 specimens with adherent tissue (96%). Among 61 fractured components from conical filters, 35 had extravascular penetration whereas 26 remained intravascular (11 free-floating in IVC, 15 embolized centrally), and EM revealed fracture modes of high-cycle fatigue (n = 53), overload (n = 6), and indeterminate (n = 2). Following retrieval, previously prescribed lifelong anticoagulation was discontinued in 30 of 31 patients (97%). Filter-related symptoms from IVC occlusion, component embolization, and penetration-induced abdominal pain, duodenal injury, and/or small-bowel volvulus were alleviated in all 26 cases (100%). There were no long-term complications at a mean follow-up of 371 days (range, 67-878 d).The risk of filter fracture increases after 408 days (ie,>1 y) of implantation and is associated with symptomatic extravascular penetration and/or intravascular embolization. Complex methods can be used to safely remove these devices, alleviate filter-related morbidity, and allow cessation of anticoagulation.

    View details for DOI 10.1016/j.jvir.2013.01.008

    View details for PubMedID 23523157

  • Correlation of the Diameter of the Left Common Iliac Vein with the Risk of Lower-extremity Deep Venous Thrombosis JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Carr, S., Chan, K., Rosenberg, J., Kuo, W. T., Kothary, N., Hovsepian, D. M., Sze, D. Y., Hofmann, L. V. 2012; 23 (11): 1467-1472


    Compression of the left common iliac vein (CIV; LCIV) is a known risk factor for lower-extremity deep vein thrombosis (DVT). This study was performed to model the probability of DVT based on LCIV diameter and apply this to a quantitative DVT risk factor scoring system.Medical records were used to identify female patients younger than 45 years of age who were diagnosed with lower-extremity DVT (n = 21) and age-matched control subjects (n = 26) who presented to the emergency department with abdominal pain. Minimum CIV diameters were measured on computed tomography. Based on published reporting standards, 13 risk factors were scored for patients diagnosed with left-sided DVT and for control subjects. The association between vein diameter and DVT was examined by Mann-Whitney test. Odds of DVT based on vein diameter was assessed by logistic regression.Mean minimum LCIV diameters were 4.0 mm for patients with DVT and 6.5 mm for patients without DVT (P = .001). The odds of left DVT increased by a factor of 1.68 for each millimeter decrease in LCIV diameter (odds ratio = 1.68; P = .006; 95% confidence interval, 1.16-2.43). As the risk factor score increased, the relationship between diameter and risk for DVT became stronger; identical LCIV diameters were associated wtih a higher probability of developing DVT if the risk factor score was higher.Stenosis of the LCIV was found to be a strong independent risk factor for development of DVT. Moreover, each millimeter decrease in CIV diameter increased the odds of DVT by a factor of 1.68.

    View details for DOI 10.1016/j.jvir.2012.07.030

    View details for PubMedID 23101919

  • Complex Retrieval of Embedded IVC Filters: Alternative Techniques and Histologic Tissue Analysis CARDIOVASCULAR AND INTERVENTIONAL RADIOLOGY Kuo, W. T., Cupp, J. S., Louie, J. D., Kothary, N., Hofmann, L. V., Sze, D. Y., Hovsepian, D. M. 2012; 35 (3): 588-597


    We evaluated the safety and effectiveness of alternative endovascular methods to retrieve embedded optional and permanent filters in order to manage or reduce risk of long-term complications from implantation. Histologic tissue analysis was performed to elucidate the pathologic effects of chronic filter implantation.We studied the safety and effectiveness of alternative endovascular methods for removing embedded inferior vena cava (IVC) filters in 10 consecutive patients over 12 months. Indications for retrieval were symptomatic chronic IVC occlusion, caval and aortic perforation, and/or acute PE (pulmonary embolism) from filter-related thrombus. Retrieval was also performed to reduce risk of complications from long-term filter implantation and to eliminate the need for lifelong anticoagulation. All retrieved specimens were sent for histologic analysis.Retrieval was successful in all 10 patients. Filter types and implantation times were as follows: one Venatech (1,495 days), one Simon-Nitinol (1,485 days), one Optease (300 days), one G2 (416 days), five Günther-Tulip (GTF; mean 606 days, range 154-1,010 days), and one Celect (124 days). There were no procedural complications or adverse events at a mean follow-up of 304 days after removal (range 196-529 days). Histology revealed scant native intima surrounded by a predominance of neointimal hyperplasia and dense fibrosis in all specimens. Histologic evidence of photothermal tissue ablation was confirmed in three laser-treated specimens.Complex retrieval methods can now be used in select patients to safely remove embedded optional and permanent IVC filters previously considered irretrievable. Neointimal hyperplasia and dense fibrosis are the major components that must be separated to achieve successful retrieval of chronic filter implants.

    View details for DOI 10.1007/s00270-011-0175-1

    View details for PubMedID 21562933

  • Intratumoral versus Intravenous Gene Therapy Using a Transcriptionally Targeted Viral Vector in an Orthotopic Hepatocellular Carcinoma Rat Model JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Kim, Y. I., Ahn, B., Ronald, J. A., Katzenberg, R., Singh, A., Paulmurugan, R., Ray, S., Gambhir, S. S., Hofmann, L. V. 2012; 23 (5): 704-711


    To evaluate the feasibility of intratumoral delivery of adenoviral vector carrying a bidirectional two-step transcriptional amplification (TSTA) system to amplify transcriptional strength of cancer-specific Survivin promoter in a hepatocellular carcinoma model.MCA-RH7777 cells were implanted in rat liver, and tumor formation was confirmed with [(18)F]fluorodeoxyglucose (18F-FDG) positron emission tomography (PET). The adenoviral vector studied had Survivin promoter driving a therapeutic gene (tumor necrosis factor-α-related apoptosis-inducing ligand [TRAIL]) and a reporter gene (firefly luciferase [FL]; Ad-pSurvivin-TSTA-TRAIL-FL). Tumor-bearing rats were administered Ad-pSurvivin-TSTA-TRAIL-FL intravenously (n = 7) or intratumorally (n = 8). For control groups, adenovirus FL under cytomegalovirus (CMV) promoter (Ad-pCMV-FL) was administered intravenously (n = 3) or intratumorally (n = 3). One day after delivery, bioluminescence imaging was performed to evaluate transduction. At 4 and 7 days after delivery, 18F-FDG-PET was performed to evaluate therapeutic efficacy.With intravenous delivery, Ad-pSurvivin-TSTA-TRAIL-FL showed no measurable liver tumor FL signal on day 1 after delivery, but showed better therapeutic efficacy than Ad-pCMV-FL on day 7 (PET tumor/liver ratio, 3.5 ± 0.58 vs 6.0 ± 0.71; P = .02). With intratumoral delivery, Ad-pSurvivin-TSTA-TRAIL-FL showed positive FL signal from all tumors and better therapeutic efficacy than Ad-pCMV-FL on day 7 (2.4 ± 0.50 vs 5.4 ± 0.78; P = .01). In addition, intratumoral delivery of Ad-pSurvivin-TSTA-TRAIL-FL demonstrated significant decrease in tumoral viability compared with intravenous delivery (2.4 ± 0.50 vs 3.5 ± 0.58; P = .03).Intratumoral delivery of a transcriptionally targeted therapeutic vector for amplifying tumor-specific effect demonstrated better transduction efficiency and therapeutic efficacy for liver cancer than systemic delivery, and may lead to improved therapeutic outcome for future clinical practice.

    View details for DOI 10.1016/j.jvir.2012.01.053

    View details for Web of Science ID 000303557000020

    View details for PubMedID 22387029

    View details for PubMedCentralID PMC4132166

  • 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

  • Catheter-directed thrombolysis for acute DVT LANCET Hofmann, L. V., Kuo, W. T. 2012; 379 (9810): 3-4

    View details for DOI 10.1016/S0140-6736(11)61875-8

    View details for PubMedID 22172245

  • 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

  • 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

  • Portal Venous Remodeling After Endovascular Reduction of Pediatric Autogenous Portosystemic Shunts JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Stewart, J. K., Kuo, W. T., Hovsepian, D. M., Hofmann, L. V., Bonham, C. A., Sze, D. Y. 2011; 22 (8): 1199-1205


    Patients with autogenous native vessel portosystemic shunts, whether surgical or congenital, may experience complications of excess shunt flow, including hepatopulmonary syndrome (HPS), hepatic encephalopathy (HE), and hepatic insufficiency. The authors explored endovascular reduction or occlusion of autogenous portosystemic shunts using methods commonly employed in transjugular intrahepatic portosystemic shunt (TIPS) reduction in four pediatric patients. Before treatment, the patients had hypoplastic, atrophic, or thrombosed portal veins. Following intervention, symptoms of overshunting resolved or improved in all patients without major complications. The innate plasticity of the pediatric portal venous system allowed for hypertrophy or development and maturation of cavernous transformations to accommodate increased hepatopetal blood flow and pressure.

    View details for DOI 10.1016/j.jvir.2011.01.438

    View details for PubMedID 21801995

  • In vivo MRSI of hyperpolarized [1-C-13]pyruvate metabolism in rat hepatocellular carcinoma NMR IN BIOMEDICINE Darpolor, M. M., Yen, Y., Chua, M., Xing, L., Clarke-Katzenberg, R. H., Shi, W., Mayer, D., Josan, S., Hurd, R. E., Pfefferbaum, A., Senadheera, L., So, S., Hofmann, L. V., Glazer, G. M., Spielman, D. M. 2011; 24 (5): 506-513


    Hepatocellular carcinoma (HCC), the primary form of human adult liver malignancy, is a highly aggressive tumor with average survival rates that are currently less than 1 year following diagnosis. Most patients with HCC are diagnosed at an advanced stage, and no efficient marker exists for the prediction of prognosis and/or response(s) to therapy. We have reported previously a high level of [1-(13)C]alanine in an orthotopic HCC using single-voxel hyperpolarized [1-(13)C]pyruvate MRS. In the present study, we implemented a three-dimensional MRSI sequence to investigate this potential hallmark of cellular metabolism in rat livers bearing HCC (n = 7 buffalo rats). In addition, quantitative real-time polymerase chain reaction was used to determine the mRNA levels of lactate dehydrogenase A, nicotinamide adenine (phosphate) dinucleotide dehydrogenase quinone 1 and alanine transaminase. The enzyme levels were significantly higher in tumor than in normal liver tissues within each rat, and were associated with the in vivo MRSI signal of [1-(13)C]alanine and [1-(13)C]lactate after a bolus intravenous injection of [1-(13)C]pyruvate. Histopathological analysis of these tumors confirmed the successful growth of HCC as a nodule in buffalo rat livers, revealing malignancy and hypervascular architecture. More importantly, the results demonstrated that the metabolic fate of [1-(13)C]pyruvate conversion to [1-(13)C]alanine significantly superseded that of [1-(13)C]pyruvate conversion to [1-(13)C]lactate, potentially serving as a marker of HCC tumors.

    View details for DOI 10.1002/nbm.1616

    View details for Web of Science ID 000291597200009

    View details for PubMedID 21674652

    View details for PubMedCentralID PMC3073155

  • 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

  • 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

  • Catheter-directed Therapy for the Treatment of Massive Pulmonary Embolism: Systematic Review and Meta-analysis of Modem Techniques JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Kuo, W. T., Gould, M. K., Louie, J. D., Rosenberg, J. K., Sze, D. Y., Hofmann, L. V. 2009; 20 (11): 1431-1440


    Systemic thrombolysis for the treatment of acute pulmonary embolism (PE) carries an estimated 20% risk of major hemorrhage, including a 3%-5% risk of hemorrhagic stroke. The authors used evidence-based methods to evaluate the safety and effectiveness of modern catheter-directed therapy (CDT) as an alternative treatment for massive PE.The systematic review was initiated by electronic literature searches (MEDLINE, EMBASE) for studies published from January 1990 through September 2008. Inclusion criteria were applied to select patients with acute massive PE treated with modern CDT. Modern techniques were defined as the use of low-profile devices (< or =10 F), mechanical fragmentation and/or aspiration of emboli including rheolytic thrombectomy, and intraclot thrombolytic injection if a local drug was infused. Relevant non-English language articles were translated into English. Paired reviewers assessed study quality and abstracted data. Meta-analysis was performed by using random effects models to calculate pooled estimates for complications and clinical success rates across studies. Clinical success was defined as stabilization of hemodynamics, resolution of hypoxia, and survival to hospital discharge.Five hundred ninety-four patients from 35 studies (six prospective, 29 retrospective) met the criteria for inclusion. The pooled clinical success rate from CDT was 86.5% (95% confidence interval [CI]: 82.1%, 90.2%). Pooled risks of minor and major procedural complications were 7.9% (95% CI: 5.0%, 11.3%) and 2.4% (95% CI: 1.9%, 4.3%), respectively. Data on the use of systemic thrombolysis before CDT were available in 571 patients; 546 of those patients (95%) were treated with CDT as the first adjunct to heparin without previous intravenous thrombolysis.Modern CDT is a relatively safe and effective treatment for acute massive PE. At experienced centers, CDT should be considered as a first-line treatment for patients with massive PE.

    View details for DOI 10.1016/j.jvir.2009.08.002

    View details for PubMedID 19875060

  • Computed Tomography-Guided Percutaneous Needle Biopsy of Pulmonary Nodules: Impact of Nodule Size on Diagnostic Accuracy CLINICAL LUNG CANCER Kothary, N., Lock, L., Sze, D. Y., Hofmann, L. V. 2009; 10 (5): 360-363


    This study was undertaken to compare the diagnostic accuracy and complication rate of computed tomography (CT)-guided percutaneous lung biopsies of lung nodules1.5 cm in diameter.A total of 139 patients (age range, 18-89 years; mean, 62.5 years) underwent CT-guided percutaneous fine-needle aspiration biopsy or 20-gauge core biopsy using an automated biopsy gun. In 37 patients, the lung nodule measured 1.5 cm (mean, 2.8 cm). Diagnostic accuracy was determined by cytopathology results. Major and minor complications were documented.Overall diagnostic accuracy, pneumothorax rate, and thoracostomy tube insertion rates were 67.6%, 34.5%, and 5%, respectively. Of the 98 patients with malignancy, 77 patients (78.6%) had a definite diagnostic biopsy. Overall, nodules>1.5 cm were statistically more likely to result in a diagnostic specimen (73.5%) than nodules1.5 cm than in those1.5 cm. However, the diagnostic accuracy for malignancy is high in both groups, with a low risk of complications.

    View details for DOI 10.3816/CLC.2009.n.049

    View details for PubMedID 19808195

  • A Primer on Image-guided Radiation Therapy for the Interventional Radiologist JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Kothary, N., Dieterich, S., Louie, J. D., Koong, A. C., Hofmann, L. V., Sze, D. Y. 2009; 20 (7): 859-862


    The use of image-guided radiation therapy in thoracic and abdominal tumors is increasing. Herein, the authors review the process of image-guided radiation therapy and describe techniques useful for optimal implantation of fiducial markers.

    View details for DOI 10.1016/j.jvir.2009.03.037

    View details for PubMedID 19481470

  • 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

  • Therapies for acute and chronic deep venous thrombosis. Clinical advances in hematology & oncology : H&O Hofmann, L. V. 2009; 7 (5): 301-303

    View details for PubMedID 19521317

  • Percutaneous Implantation of Fiducial Markers for Imaging-Guided Radiation Therapy AMERICAN JOURNAL OF ROENTGENOLOGY Kothary, N., Dieterich, S., Louie, J. D., Chang, D. T., Hofmann, L. V., Sze, D. Y. 2009; 192 (4): 1090-1096


    The use of imaging-guided radiation therapy (IGRT) to treat thoracic and abdominal tumors is increasing. In this article, we review the process of IGRT and describe techniques to implant fiducial markers in the optimal geometry.Implantation of fiducial markers can be challenging. A better understanding of the physics of IGRT can help optimize fiducial marker placement for precise tumor targeting.

    View details for DOI 10.2214/AJR.08.1399

    View details for PubMedID 19304719

  • Factors Portending Endoleak Formation After Thoracic Aortic Stent-Graft Repair of Complicated Aortic Dissection CIRCULATION-CARDIOVASCULAR INTERVENTIONS Sze, D. Y., Van den Bosch, M. A., Dake, M. D., Miller, D. C., Hofmann, L. V., Varghese, R., Malaisrie, S. C., van der Starre, P. J., Rosenberg, J., Mitchell, R. S. 2009; 2 (2): 105-112


    Endoleaks after stent-graft repair of aortic dissections are poorly understood but seem substantially different from those seen after aneurysm repair. We studied anatomic and clinical factors associated with endoleaks in patients who underwent stent-graft repair of complicated type B aortic dissections.From 2000 to 2007, 37 patients underwent stent-graft repair of acute (< or =14 days; n=23), subacute (15 to 90 days; n=10) or chronic (>90 days; n=4) complicated type B aortic dissections using the Gore Thoracic Excluder (n=17) or TAG stent-grafts (n=20) under an investigator-sponsored protocol. Endoleaks were classified as imperfect proximal seal, flow through fenestrations or branches, or complex (both). Variables studied included coverage of the left subclavian artery, aortic curvature, completeness of proximal apposition, dissection chronicity, and device used. Endoleaks were found during follow-up (mean, 22 months) in 59% of patients, and they were associated with coverage of the left subclavian artery (complex, P<0.001), small radius of curvature (type 1 and complex, P=0.05), and greatest length of unapposed proximal stent graft (complex, P<0.0001). During follow-up, 10 endoleaks resolved spontaneously, 6 required reintervention for false lumen dilatation, and 2 were stable without clinical consequences.Endoleaks are common after stent-graft repair of aortic dissection and may lead to false lumen enlargement necessitating reintervention. Anatomic complexities such as acute aortic curvature and covered side branches were associated with endoleaks, illustrating the need for dissection-specific device development.

    View details for DOI 10.1161/CIRCINTERVENTIONS.108.819722

    View details for PubMedID 20031703

  • Safety and Efficacy of Percutaneous Fiducial Marker Implantation for Image-guided Radiation Therapy JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Kothary, N., Heit, J. J., Louie, J. D., Kuo, W. T., Loo, B. W., Koong, A., Chang, D. T., Hovsepian, D., Sze, D. Y., Hofmann, L. V. 2009; 20 (2): 235-239


    To evaluate the safety and technical success rate of percutaneous fiducial marker implantation in preparation for image-guided radiation therapy.From January 2003 to January 2008, we retrospectively reviewed 139 percutaneous fiducial marker implantations in 132 patients. Of the 139 implantations, 44 were in the lung, 61 were in the pancreas, and 34 were in the liver. Procedure-related major and minor complications were documented. Technical success was defined as implantation enabling adequate treatment planning and computed tomographic simulation.The major and minor complication rates were 5% and 17.3%, respectively. Pneumothorax after lung implantation was the most common complication. Pneumothoraces were seen in 20 of the 44 lung implantations (45%); a chest tube was required in only seven of the 44 lung transplantations (16%). Of the 139 implantations, 133 were successful; in six implantations (4.3%) the fiducial markers migrated and required additional procedures or alternate methods of implantation.Percutaneous implantation of fiducial marker is a safe and effective procedure with risks that are similar to those of conventional percutaneous organ biopsy.

    View details for DOI 10.1016/j.jvir.2008.09.026

    View details for PubMedID 19019700

  • Biopsy of Cardiac Masses Using a Stabilized Intracardiac Echocardiography-guided System JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Sze, D. Y., Lee, D. P., Hofmann, L. V., Petersen, B. 2008; 19 (11): 1662-1667


    Biopsy of a cardiac mass remains a difficult and risky procedure. Successful sampling of target tissue is hampered by continuous cardiac motion and blood flow. Because the surrounding tissues are vascular, complications can include hemorrhage, tamponade, arrhythmia, embolization, and death. Conventional imaging modalities are of limited utility in this dynamic environment. The present report describes the use of the instrumentation system originally designed for creation of direct portocaval shunts with intracardiac echocardiography imaging to perform core biopsies of cardiac and juxtacardiac masses in six patients. There were no hemorrhagic complications, and pathologic diagnoses were obtained in five of six cases.

    View details for DOI 10.1016/j.jvir.2008.08.001

    View details for Web of Science ID 000260694700020

    View details for PubMedID 18818096

  • Catheter-directed embolectomy, fragmentation, and thrombolysis for the treatment of massive pulmonary embolism after failure of systemic thrombolysis CHEST Kuo, W. T., Van den Bosch, M. A., Hofmann, L. V., Louie, J. D., Kothary, N., Sze, D. Y. 2008; 134 (2): 250-254


    The standard medical management for patients in extremis from massive pulmonary embolism (PE) is systemic thrombolysis, but the utility of this treatment relative to catheter-directed intervention (CDI) is unknown. We evaluated the effectiveness of CDI as part of a treatment algorithm for life-threatening PE.A retrospective review was performed on 70 consecutive patients with suspected acute PE over a 10-year period (from 1997 to 2006) who had been referred for pulmonary angiography and/or intervention. The criteria for study inclusion were patients who received CDI due to angiographically confirmed massive PE and hemodynamic shock (shock index, > or = 0.9). CDI involved suction embolectomy and fragmentation with or without catheter thrombolysis.Twelve patients were treated with CDI. There were seven men and five women (mean age, 56 years; age range, 21 to 80 years). Seven patients (58%) were referred for CDI after failing systemic infusion with 100 mg of tissue plasminogen activator, and five patients (42%) had contraindications to systemic thrombolysis. Catheter-directed fragmentation and embolectomy were performed in all patients (100%). Additionally, catheter-guided thrombolysis was performed in eight patients (67%). Technical success was achieved in 12 of 12 cases (100%). There were no major procedural complications (0%). Significant hemodynamic improvement (shock index, < 0.9) was observed in 10 of 12 cases (83%). The remaining two patients (17%) died secondary to cardiac arrest within 24 h. Ten of 12 patients (83%) survived and remained stable until hospital discharge (mean duration, 20 days; range, 3 to 51 days).In the setting of hemodynamic shock from massive PE, CDI is potentially a life-saving treatment for patients who have not responded to or cannot tolerate systemic thrombolysis.

    View details for DOI 10.1378/chest.07-2846

    View details for PubMedID 18682455

  • Reninoma: case report and literature review JOURNAL OF HYPERTENSION Wonga, L., Hsu, T. H., Perlroth, M. G., Hofmann, L. V., Haynes, C. M., Katznelson, L. 2008; 26 (2): 368-373


    Reninoma is a tumor of the renal juxtaglomerular cell apparatus that causes hypertension and hypokalemia via hypersecretion of renin. We describe a case of reninoma and provide a review of the literature, with a discussion emphasizing the diagnostic evaluation for such patients. The subject had persistent elevation of both plasma renin activity (PRA) and aldosterone. Imaging studies revealed the presence of a lesion in the renal cortex, which was further identified as a renin-producing lesion via selective venous catheterization following administration of an angiotensin-converting enzyme inhibitor (ACE-I). Following partial nephrectomy, the PRA and plasma aldosterone levels declined rapidly and the blood pressure and potassium supplementation requirements normalized. This case demonstrates the utility of both appropriate imaging studies and selective venous catheterization following provocative administration of an ACE-I for diagnosis.

    View details for Web of Science ID 000252778100030

    View details for PubMedID 18192852

  • Catheter-directed intervention for acute pulmonary embolism - A shining saber CHEST Kuo, W. T., Sze, D. Y., Hofmann, L. V. 2008; 133 (1): 317-318

    View details for DOI 10.1378/chest.07-2278

    View details for Web of Science ID 000252385600063

    View details for PubMedID 18187767

  • 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

  • Quiz page. Fibromuscular dysplasia of the right renal artery. American journal of kidney diseases van den Bosch, M. A., Sze, D. Y., Hofmann, L. V. 2007; 49 (5): A43-4

    View details for PubMedID 17687806

  • Intrabiliary MR imaging: Assessment of biliary obstruction with use of an intraluminal MR receiver coil JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Weiss, C. R., Georgiades, C., Hofmann, L. V., Schulick, R., Choti, M., Thuluvath, P., Bluemke, D. A., Arepally, A. 2006; 17 (5): 845-853


    The primary aim of this study was to determine whether intrabiliary magnetic resonance (MR) imaging is feasible in a clinical setting and to optimize MR imaging parameters for the technique. In addition, it was attempted to determine the accuracy of intrabiliary MR imaging in the setting of biliary obstruction of unknown cause.Intrabiliary MR was performed prospectively in 15 patients with biliary obstruction of unknown cause. A 0.030-inch MR intravascular receiver coil was placed in an existing biliary tube. Intrabiliary MR was performed on a 1.5-T system. T1-weighted, T2-weighted, and single-shot fast spin-echo images were acquired. T1-weighted images were also acquired after the administration of a gadolinium contrast agent. Signal intensity analysis was conducted in the region of the common bile duct. Accuracy of intrabiliary MR, computed tomography (CT), MR, and cholangiography were determined by correlation with surgical pathologic findings.Intrabiliary MR was successfully performed in 14 of 15 patients. MR examinations were performed in less than 1 hour. The signal-to-noise ratio in the region of the common bile duct with the intrabiliary MR technique was increased by a factor of 9 compared with standard surface-coil MR imaging (P < .00001). The mean n-plane resolution achieved was 740 +/- 20 microm x 1,150 +/- 20 microm obtained with use of a field of view of 18 cm x 18 cm (range, 15-24 cm) and a matrix of 256 x 160. Of the pulse sequences tested, the gadolinium-enhanced T1-weighted image was the best for identifying tumor and delineating tumor margins. Intrabiliary MR had a higher sensitivity than CT (100% vs 50%), a higher specificity than cholangiography (80% vs 20%), and a better correlation (P = .015) with surgical pathologic findings than CT, MR imaging, or cholangiography.Intrabiliary MR was well tolerated in a clinical setting and provided high spatial resolution and excellent contrast between the biliary lumen and adjacent structures. Intrabiliary MR demonstrated an advantage in detecting the presence or absence of biliary malignancies compared with currently available standard imaging techniques. The technique may be useful to evaluate biliary obstruction of unknown cause.

    View details for DOI 10.1097/01.RVI.0000215938.27787.1D

    View details for Web of Science ID 000237612300013

    View details for PubMedID 16687751

  • Intravascular magnetic resonance/radiofrequency may enhance gene therapy for prevention of in-stent neointimal hyperplasia. Academic radiology Gao, F., Qiu, B., Kar, S., Zhan, X., Hofmann, L. V., Yang, X. 2006; 13 (4): 526-530


    We evaluated the potential of using intravascular magnetic resonance (MR)/radiofrequency (RF) to enhance vascular endothelial growth factor (VEGF) gene therapy of in-stent neointimal hyperplasia.By using a catheter-based approach, VEGF/lentivirus was locally transferred into 10 (five paired) bilateral femoral-iliac arteries of five hypercholesterolemic pigs, whereas the right arteries were heated up to approximately 41 degrees C by using an intravascular MR/RF system. Then, identical stents were placed immediately into the bilateral VEGF-targeted arteries to create in-stent neointimal hyperplasia. At day 60 after gene/stent interventions, the targeted arteries were harvested for histological correlation.X-Ray angiography-detectable in-stent stenoses were found in three of the arteries treated with VEGF genes only, whereas there were no in-stent stenoses in arteries treated by using MR/RF-heated VEGF genes. Correlative histological examination confirmed a 138% reduction in average thickness of neointimal hyperplasia in VEGF/RF-treated arteries compared with VEGF-only-treated arteries (P < .01).We report a potential method of using an intravascular MR/RF heating technique to enhance gene therapy of in-stent restenosis.

    View details for PubMedID 16554234

  • Society of interventional radiology position statement: Treatment of acute iliofemoral deep vein thrombosis with use of adjunctive catheter-directed intrathrombus thrombolysis JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Vedantham, S., Millward, S. F., Cardella, J. F., Hofmann, L. V., Razavi, M. K., Grassi, C. J., Sacks, D., Kinney, T. B. 2006; 17 (4): 613-616
  • Quality improvement guidelines for the treatment of lower extremity deep vein thrombosis with use of endovascular thrombus removal JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Vedantham, S., Thorpe, P. E., Cardella, J. F., Grassi, C. J., Patel, N. H., Ferral, H., Hofmann, L. V., D'othee, B. M., Antonaci, V. P., Brountzos, E. N., Brown, D. B., Martin, L. G., Matsumoto, A. H., Meranze, S. G., MILLER, D. L., Millward, S. F., Min, R. J., Neithamer, C. D., Rajan, D. K., Rholl, K. S., Schwartzberg, M. S., Swan, T. L., Towbin, R. B., Wiechmann, B. N., Sacks, D. 2006; 17 (3): 435-448
  • Reporting standards for endovascular treatment of lower extremity deep vein thrombosis JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Vedantham, S., Grassi, C. J., Ferral, H., Patel, N. H., Thorpe, P. E., Antonacci, V. P., D'othee, B. M., Hofmann, L. V., Cardella, J. F., Kundu, S., Lewis, C. A., Schwartzberg, M. S., Min, R. J., Sacks, D. 2006; 17 (3): 417-434
  • Development of a research agenda for endovascular treatment of venous thromboembolism: Proceedings from a multidisciplinary consensus panel JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Vedantham, S., Rundback, J. H., Comerota, A. J., Hunter, D. W., Meissner, M. H., Hofmann, L. V., Horne, M., Gloviczki, P., Andrews, R. T., Fan, C. M., Hume, K. M., Goldhaber, S. K., Tapson, V. F., Razavi, M. K., Min, R. J. 2005; 16 (12): 1567-1573

    View details for Web of Science ID 000234221800001

    View details for PubMedID 16371519

  • Constitutively active HIF-1 alpha improves perfusion and arterial remodeling in an endovascular model of limb ischemia CARDIOVASCULAR RESEARCH Patel, T. H., Kimura, H., Weiss, C. R., Semenza, G. L., Hofmann, L. V. 2005; 68 (1): 144-154


    Hypoxia-inducible factor 1 (HIF-1) regulates the expression of angiogenic growth factors. We analyzed the effect of intramuscular (i.m.) delivery of AdCA5, an adenovirus encoding a constitutively active form of the HIF-1alpha subunit, in a novel model of limb ischemia.AdCa5 or AdLacZ (6 x 10(8) pfu) was injected into male New Zealand White rabbits that were untreated or subjected to occlusion of the left superficial femoral artery by endovascular coils. Expression of mRNAs was quantified 1, 3, and 7 days after adenovirus injection into rabbits without occlusion. Calf blood pressure (BP), angiography, and immunohistochemical analyses were performed 14 days after arterial occlusion and adenovirus injection.AdCA5 increased the expression of HIF-1alpha, monocyte chemotactic protein-1, placental growth factor, platelet-derived growth factor B, stromal-derived factor 1alpha, and vascular endothelial growth factor (VEGF) mRNA as well as HIF-1alpha and VEGF protein. On day 14, AdCA5-injected limbs showed improved calf BP ratios (0.89+/-0.13 vs. 0.51+/-0.05, p=0.02), angiographic perfusion scores (3.50+/-0.56 vs. 8.33+/-1.31, p=0.007), and distal deep femoral artery diameter ratio (1.84+/-0.25 vs. 0.93+/-0.22, p=0.02) relative to those receiving AdLacZ. The capillary/myocyte ratio (0.93+/-0.03 vs. 0.78+/-0.06, p=0.04) and arterial luminal area (0.32+/-0.05 mm2 vs. 0.21+/-0.03 mm2, p=0.04) were significantly increased in the AdCA5 group.In a model that resembles atherosclerotic obstruction of peripheral arteries in patients, the i.m. administration of AdCA5 promoted arteriogenic and angiogenic responses.

    View details for DOI 10.1016/j.cardiores.2005.05.002

    View details for Web of Science ID 000232236400018

    View details for PubMedID 15921668

  • Radiofrequency-enhanced vascular gene transduction and expression for intravascular MR imaging-guided therapy: Feasibility study in pigs RADIOLOGY Du, X. Y., Qiu, B. S., Zhan, X. C., Kolmakova, A., Gao, F. B., Hofmann, L. V., Cheng, L. Z., Chatterjee, S., Yang, X. M. 2005; 236 (3): 939-944


    To evaluate the feasibility of radiofrequency (RF)-enhanced vascular gene transduction and expression by using a magnetic resonance (MR) imaging-heating guidewire as an intravascular heating vehicle during MR imaging-guided therapy.The institutional committee for animal care and use approved the experimental protocol. The study included in vitro evaluation of the use of RF energy to enhance gene transduction and expression in vascular cells, as well as in vivo validation of the feasibility of intravascular MR imaging-guided RF-enhanced vascular gene transduction and expression in pig arteries. For in vitro experiments, approximately 10(4) vascular smooth muscle cells were seeded in each of four chambers of a cell culture plate. Next, 1 mL of a green fluorescent protein gene (gfp)-bearing lentivirus was added to each chamber. Chamber 4 was heated at approximately 41 degrees C for 15 minutes by using an MR imaging-heating guidewire connected to a custom RF generator. At day 6 after transduction, the four chambers were examined and compared at confocal microscopy to determine the efficiency of gfp transduction and expression. For the in vivo experiments, a lentivirus vector bearing a therapeutic gene, vascular endothelial growth factor 165 (VEGF-165), was transferred by using a gene delivery balloon catheter in 18 femoral-iliac arteries (nine artery pairs) in domestic pigs and Yucatan pigs with atherosclerosis. During gene infusion, one femoral-iliac artery in each pig was heated to approximately 41 degrees C with RF energy transferred via the intravascular MR imaging-heating guidewire, while the contralateral artery was not heated (control condition). At day 6, the 18 arteries were harvested for quantitative Western blot analysis to compare VEGF-165 transduction and expression efficiency between RF-heated and nonheated arterial groups.Confocal microscopy showed gfp expression in chamber 4 that was 293% the level of expression in chamber 1 (49.6% +/- 25.8 vs 16.8% +/- 8.0). Results of Western blot analysis showed VEGF-165 expression for normal arteries in the RF-heated group that was 300% the level of expression in the nonheated group (70.4 arbitrary units [au] +/- 107.1 vs 23.5 au +/- 29.8), and, for atherosclerotic arteries in the RF-heated group, 986% the level in the nonheated group (129.2 au +/- 100.3 vs 13.1 au +/- 4.9).Simultaneous monitoring and enhancement of vascular gene delivery and expression is feasible with the MR imaging-heating guidewire.

    View details for DOI 10.1148/radiol.2363041021

    View details for Web of Science ID 000231412600026

    View details for PubMedID 16040894

  • Endovascular model of rabbit Hindlimb ischemia: A platform to evaluate therapeutic angiogenesis JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Liddell, R. P., Patel, T. H., Weiss, C. R., Lee, D. S., Matsuhashi, T., Brown, P. R., Gabrielson, K. L., Rodriguez, E. R., Eng, J., Kimura, H., Hofmann, L. V. 2005; 16 (7): 991-998


    Current animal hindlimb ischemia models involve surgical ligation of the femoral artery and delivery of therapeutic angiogenic agents into the adductor compartment. The authors hypothesize that an endovascular model of hindlimb ischemia would be a more appropriate platform, closely resembling atherosclerosis by occluding the vessel from within, causing less inflammation, wound healing and subsequent collateralization.The left superficial femoral artery in 17 rabbits was occluded by endovascular coil embolization (n=9) or surgical ligation (n=8). Animals (n=3; in each group) were sacrificed on day 3 to determine the arteriolar luminal area, number of arterioles, microsphere determined perfusion, and degree of inflammation. On day 28, the remaining animals underwent calf blood pressure measurements and angiography to determine the number of collaterals and diameter of vessels supplying the hindlimb.Immediate postprocedure (day 0) and presacrifice (day 3 or 28) occlusion rates were 89% (eight of nine rabbits) and 100% for the endovascular model; 100% and 100% for the surgical model, respectively. Hindlimb paralysis and muscle atrophy was found in one surgical animal. On day 3, there was an increase in hindlimb perfusion (surgery, 0.04+/-0.01; endovascular, 0.02+/-0.01; P=.02), an increase in arteriolar luminal area (surgery, 481 microm+/-240; endovascular, 345 microm+/-151; P=.04), and a trend toward more inflammation (surgery, 5.5+/-3.8; endovascular, 2.5+/-3.0; P=.08) in the surgical group. There was no difference in number of vessels between both groups. On day 28 there was no difference in the calf blood pressure ratios or in the number of collaterals. However, there was enlargement of the distal profunda femoris artery, the vessel closest to the surgical incision, in the surgical group (L/R ratio: immediate post-occlusion, 1.06+/-0.11; day 28, 1.27+/-0.08; P=.02).The endovascular model was efficacious in providing occlusion of the superficial femoral artery, and induced less of an arteriogenic response compared with the surgical model. The authors believe that this endovascular model is a superior platform for studying therapeutic angiogenic agents.

    View details for DOI 10.1097/01.RVI.0000161381.48445.48

    View details for Web of Science ID 000230361500009

    View details for PubMedID 16002507

  • Human peripheral arteries: Feasibility of transvenous intravascular MR imaging of the arterial wall RADIOLOGY Hofmann, L. V., Liddell, R. P., Eng, J., Wasserman, B. A., Arepally, A., Lee, D. S., Bluemke, D. A. 2005; 235 (2): 617-622


    Feasibility of in vivo transvenous intravascular magnetic resonance (MR) imaging of the human arterial wall was determined. All subjects provided written informed consent, and institutional review board approved the study. Six arteries in six patients were imaged with a guidewire placed in the iliac vein (n = 5) or left renal vein (n = 1). Pre- and postcontrast T1-weighted and T2-weighted transvenous MR imaging were performed. An atherosclerotic plaque with a fibrous cap was identified on 27 (42%) of 64 images of veins without stents; intimal hyperplasia in a renal artery with a stent was identified on 12 images. Contrast-to-noise ratios (CNRs) on arterial wall postcontrast T1-weighted images were superior to those on images obtained with other sequences (P < .001), and the postcontrast images demonstrated the greatest number of plaques with a low-signal intensity core and fibrous cap. Preliminary results show that transvenous MR imaging is feasible for high-spatial-resolution imaging of the arterial wall and atherosclerotic plaque. Postcontrast T1-weighted imaging affords greatest CNR for the arterial wall.

    View details for DOI 10.1148/radiol.2352040340

    View details for Web of Science ID 000228571200038

    View details for PubMedID 15858101

  • Endovascular management of May-Thurner syndrome AMERICAN JOURNAL OF ROENTGENOLOGY Grunwald, M. R., Goldberg, M. J., Hofmann, L. V. 2004; 183 (5): 1523-1524

    View details for Web of Science ID 000224685700059

    View details for PubMedID 15505333

  • Extracorporeal expulsion of a vascular endograft used to treat a mycotic aneurysm JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Patel, T. H., Eggleston, J., Weiss, C. R., Hofmann, L. V. 2004; 15 (10): 1157-1160


    A 65-year-old woman with a right common iliac artery mycotic aneurysm and an overlying sacral pressure ulcer was treated with placement of a vascular endograft. The mycotic aneurysm was successfully excluded, but 3 months after the procedure, the endograft was expelled through the wound. Fortunately, the patient had minimal clinical sequelae. This case emphasizes the importance of frequent noninvasive imaging of mycotic aneurysms treated with endografts. A rigorous postoperative imaging protocol is proposed based on the current regimen for abdominal aortic aneurysm surveillance after endograft implantation.

    View details for DOI 10.1097/01.RVI.0000137403.06053.75

    View details for Web of Science ID 000227678700019

    View details for PubMedID 15466805

  • Hilar cholangiocarcinoma: Staging with intrabiliary MRI AMERICAN JOURNAL OF ROENTGENOLOGY Arepally, A., Georgiades, C., Hofmann, L. V., Choti, M., Thuluvath, P., Bluemke, D. A. 2004; 183 (4): 1071-1074

    View details for Web of Science ID 000224217200033

    View details for PubMedID 15385306

  • Safety and hemodynamic effects of pulmonary angiography in patients with pulmonary hypertension: 10-year single-center experience AMERICAN JOURNAL OF ROENTGENOLOGY Hofmann, L. V., Lee, D. S., Gupta, A., Arepally, A., Sood, S., Girgis, R., Eng, J. 2004; 183 (3): 779-786


    We sought to examine the incidence of complications and change in pulmonary artery pressure in patients with pulmonary hypertension who were undergoing pulmonary angiography.A retrospective review was performed for all patients who underwent pulmonary angiography over a 10-year period at a single institution. Patients with moderate pulmonary hypertension (pulmonary artery pressure, 30-59 mm Hg) and severe pulmonary hypertension (pulmonary artery pressure, >/= 60 mm Hg) served as the study population. Demographic data, clinical indication, pre- and postcontrast pulmonary artery pressure measurements, type of pulmonary hypertension, contrast agent volume, complications, and American Society of Anesthesiologists (ASA) classification were recorded for all patients and compared.Two hundred two of 612 patients who underwent pulmonary angiography had pulmonary hypertension. Moderate pulmonary hypertension was present in 155 patients (77%) and severe pulmonary hypertension, in 47 patients (23%). Three (2.0%) of four complications were fatal. The complication rate was higher in patients with severe pulmonary hypertension compared with patients with moderate pulmonary hypertension but not statistically significant (6.3% vs 0.6%, p = 0.63). Patients with complications had a higher mean ASA score than those without complications (4.0 vs 3.0, p = 0.03). Patients with lung transplants had the greatest increase in pulmonary artery pressure after pulmonary angiography compared with all other clinical indications (16.75 +/- 12.97 mm Hg vs 5.46 +/- 6.86 mm Hg, p = 0.003).The complication rate of pulmonary angiography in patients with pulmonary hypertension is low. However, in severely ill patients with acute pulmonary hypertension, pulmonary angiography should be undertaken with extreme caution.

    View details for Web of Science ID 000223578100040

    View details for PubMedID 15333370

  • Diagnostic utility and safety of transjugular kidney biopsy in the obese patient NEPHROLOGY DIALYSIS TRANSPLANTATION Fine, D. M., Arepally, A., Hofmann, L. V., Mankowitz, S. G., Atta, M. G. 2004; 19 (7): 1798-1802


    The obese patient may be potentially at high risk for traditional percutaneous ultrasound-guided biopsy. The utility of transjugular kidney biopsy (TJKB) in this group of patients has not been established.We conducted a retrospective analysis of 37 obese patients who underwent TJKB at our centre. The kidney was approached via the right renal vein in 31 patients. Under fluoroscopy, core biopsies were obtained from the lower pole with a 19G biopsy needle. Post-procedure venogram was performed to assess for contrast extravasation indicating capsule perforation or communication with the collecting system. Patients were followed for procedure-related complications. Mean weight was 128 kg (range: 77-187 kg) and body mass index was 44 kg/m(2) (range: 34-64 kg/m(2)). Mean creatinine was 2.2 mg/dl (range: 0.5-6.5 mg/dl). Fifteen patients had diabetes, five of whom were nephrotic; 10 other patients had nephrotic range proteinuria.Of the 37 patients, six were hospitalized at the time of biopsy and three were admitted for observation. All patients returned to baseline activity the day following procedure. Histopathological diagnosis was made in 33 cases (89.2%) with a mean of 19.2 glomeruli (range: 0-62 glomeruli) per patient. There was one major complication: a delayed retroperitoneal bleed requiring multiple transfusions. Contrast extravasation outside the capsule occurred in five patients and extravasation into the collecting system occurred in three. Body mass index was not associated with number of glomeruli obtained or complication rate.TJKB in obese patients is a relatively safe, reliable and minimally invasive procedure with an excellent diagnostic yield.

    View details for Web of Science ID 000222530500020

    View details for PubMedID 15128881

  • MR-trackable intramyrocardial injection catheter MAGNETIC RESONANCE IN MEDICINE Karmarkar, P. V., Kraitchman, D. L., Izbudak, I., Hofmann, L. V., Amado, L. C., Fritzges, D., Young, R., Pittenger, M., Bulte, J. W., Atalar, E. 2004; 51 (6): 1163-1172


    There is growing interest in delivering cellular agents to infarcted myocardium to prevent postinfarction left ventricular remodeling. MRI can be effectively used to differentiate infarcted from healthy myocardium. MR-guided delivery of cellular agents/therapeutics is appealing because the therapeutics can be precisely targeted to the desired location within the infarct. In this study, a steerable intramyocardial injection catheter that can be actively tracked under MRI was developed and tested. The components of the catheter were arranged to form a loopless RF antenna receiver coil that enabled active tracking. Feasibility studies were performed in canine and porcine myocardial infarction models. Myocardial delayed-enhancement (MDE) imaging identified the infarcted myocardium, and real-time MRI was used to guide left ventricular catheterization from a carotid artery approach. The distal 35 cm of the catheter was seen under MRI with a bright signal at the distal tip of the catheter. The catheter was steered into position, the distal tip was apposed against the infarct, the needle was advanced, and a bolus of MR contrast agent and tissue marker dye was injected intramyocardially, as confirmed by imaging and postmortem histology. A pilot study involving intramyocardial delivery of magnetically labeled stem cells demonstrated the utility of the active injection catheter system.

    View details for DOI 10.1002/mrm.20086

    View details for Web of Science ID 000221835900011

    View details for PubMedID 15170836

  • Comparison of urokinase, alteplase, and reteplase for catheter-directed thrombolysis of deep venous thrombosis JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Grunwald, M. R., Hofmann, L. V. 2004; 15 (4): 347-352


    To compare the efficacy, safety, and costs associated with catheter-directed thrombolysis with urokinase (UK) and the recombinant agents alteplase (tissue plasminogen activator [TPA]) and reteplase (recombinant plasminogen activator [RPA]) in the treatment of symptomatic deep vein thrombosis (DVT).The authors conducted a retrospective analysis on 74 patients (82 limbs) who underwent treatment for DVT. Thrombosed extremities were treated with either urokinase with therapeutic heparin dosing (UK group; 38 limbs), alteplase with subtherapeutic heparin dosing (TPA group; 32 limbs), or reteplase with subtherapeutic heparin dosing (RPA group; 12 limbs). Infusion times, dosages, drug costs, success rates, and complications were compared among the groups.Gender, age, disease location, duration of symptoms, and use of additional interventional therapies did not differ statistically among the three cohorts. Median hourly infused doses, total doses, infusion times, drug costs, and success rates per limb were: UK, 11.3 (10(4)) U/hour, 4.361 million U, 40.6 hours, US dollars 6577, 97.4%; TPA, 0.57 mg/hour, 21.6 mg, 30.8 hours, US dollars 488, 96.9%; RPA, 0.74 U/hour, 21.4 U, 24.3 hours, US dollars 1787, 100.0%. Major and overall complication rates were: UK, 5.3% and 10.5%; TPA, 3.1% and 12.5%; RPA, 8.3% and 16.7%. Infusion times, success rates, and complications were not statistically different among the three groups. Alteplase and reteplase were significantly less expensive than urokinase (P <.001 and P <.01, respectively).Catheter-directed thrombolysis for the treatment of DVT is safe and effective, regardless of the agent used. However, the new recombinant agents are significantly less expensive than urokinase.

    View details for DOI 10.1097/01.RVI.0000121407.46920.15

    View details for Web of Science ID 000227677900004

    View details for PubMedID 15064337

  • Response of balloon-expandable endoprosthetic metallic stents subjected to over-expansion in vitro CARDIOVASCULAR AND INTERVENTIONAL RADIOLOGY Montague, B. J., Kakimoto, W. M., Arepally, A., Razavi, M., Dake, M. D., Hofmann, L. V. 2004; 27 (2): 158-163


    We attempted to evaluate the in vitro behavior and performance of balloon-expandable endoprosthetic metallic stents subjected to over-expansion (OE). Seventy-two balloon-expandable endoprosthetic stents, representing 22 models from six manufacturers, were overexpanded in vitro. Stents were initially expanded to their maximum manufacturer- recommended diameter and then over-expanded incrementally to their endpoints. Endpoints for OE were either stent disarticulation or an inability to undergo further expansion despite balloon insufflation to maximum burst pressure. Measurements of stent dimensions were recorded at each overexpanded diameter and comparisons were made to manufacturer's specifications. A total of 288 balloon-driven expansions were performed on 72 stents. Sixteen stents were expanded to large diameters (> or = 16 mm), 20 stents underwent OE of 50% or greater. One model tended to disarticulate after OE greater than 50%. There were five models that had a tendency to disarticulate after minimal OE. Five models were resistant to OE (25% or less OE) but did not disarticulate. Nearly all stents showed some degree of foreshortening with OE, while 36 stents underwent foreshortening of 30% or more. Models that are not recommended for OE include Intrastent, Intrastent DoubleStrut, NIR Royale and Omniflex. Good candidates for OE include Intrastent DoubleStrut LD, Palmaz large, Medtronic Extra Support Biliary Plus and Medtronic Flexible Biliary. Palmaz XL remains the only model available for expansion from 20 to 28 mm in diameter. For the remaining stents, OE is possible, however, caution should be used.

    View details for DOI 10.1007/s00270-003-4600-y

    View details for Web of Science ID 000221104200010

    View details for PubMedID 15259812

  • Therapeutic angiogenesis: the next frontier for interventional radiology. Techniques in vascular and interventional radiology Liddell, R. P., Weiss, C. R., Hofmann, L. V. 2004; 7 (1): 40-48


    The field of interventional radiology has traditionally relied on mechanical methods to treat vascular disease, such as angioplasty balloons and stents. Although there have been a number of important technical advances in endovascular devices, there are still a number of patients who are not candidates for percutaneous or surgical revascularization. As we approach the technical limits of these newer devices, therapeutic angiogenesis may play an ever-increasing role in the future. Interventional radiologists have unique delivery skills that would complement the on-going research in this area. It is the goal of this article to serve as a primer for interventional radiologists on the agents and techniques used in this exciting field.

    View details for PubMedID 15071780

  • Catheter-directed thrombolysis for the treatment of symptomatic deep vein thrombosis CIRCULATION Grunwald, M. R., Hofmann, L. V. 2004; 109 (2): E10-E10

    View details for Web of Science ID 000188250500036

    View details for PubMedID 14734512

  • Catheter-directed thrombolytic therapy for limb ischemia: current status and controversies. Journal of vascular and interventional radiology Razavi, M. K., Lee, D. S., Hofmann, L. V. 2004; 15 (1): 13-23


    Absence of urokinase from the United States market for the past 4 years has resulted in increasing experience with other plasminogen activators in catheter-directed thrombolytic therapy. The differences in the pharmacologic properties and biologic behavior of these agents may translate into clinical outcomes that are distinct. Some of these manifestations can be predicted based on the existing large clinical trials in the acute myocardial infarction literature. However, because of the fundamental differences in techniques and thrombolytic regimens, extrapolation of the coronary data may not always predict the performance of these agents in peripheral catheter-directed fibrinolysis. In this article, the current status of the available lytic agents in the treatment of limb ischemia is reviewed.

    View details for PubMedID 14709682

  • Catheter-directed thrombolytic therapy for limb ischemia: Current status and controversies JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Razavi, M. K., Lee, D. S., Hofmann, L. V. 2003; 14 (12): 1491-1501


    Absence of urokinase from the United States market for the past 4 years has resulted in increasing experience with other plasminogen activators in catheter-directed thrombolytic therapy. The differences in the pharmacologic properties and biologic behavior of these agents may translate into clinical outcomes that are distinct. Some of these manifestations can be predicted based on the existing large clinical trials in the acute myocardial infarction literature. However, because of the fundamental differences in techniques and thrombolytic regimens, extrapolation of the coronary data may not always predict the performance of these agents in peripheral catheter-directed fibrinolysis. In this article, the current status of the available lytic agents in the treatment of limb ischemia is reviewed.

    View details for DOI 10.1097/01.RVI.0000099531.29957.94

    View details for PubMedID 14654482

  • In vivo intravascular MR imaging: Transvenous technique for arterial wall Imaging JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Hofmann, L. V., Lidell, R. P., Arepally, A., Montague, B., Yang, X. M., Bluemke, D. A. 2003; 14 (10): 1317-1327


    To determine, in vivo, the potential for transvenous magnetic resonance (MR) imaging of the arterial wall and to assess appropriate MR pulse sequences for this method.MR imaging was performed on 19 vessels (right renal artery, N = 9; left renal artery N = 2; external iliac artery, N = 4; abdominal aorta, N = 4) in nine swine. The animals were either low-density lipoprotein receptor knockout (N = 5) or Yucatan mini-pigs fed an atherogenic diet for 6 to 11 weeks (N = 4). The intravascular MR coil/guide wire (IVMRG) (Surgi-Vision, Gaithersburg, MD) was introduced via the external iliac vein into the inferior vena cava (IVC). The following electrocardiograph-gated MR pulse sequences were obtained: T1-weighted precontrast with and without fat saturation and T1-weighted postcontrast with fat saturation. Two observers scored wall signal and conspicuity and classified the vessel as normal, abnormal, or stented. Images were compared with histopathologic findings.The T1-weighted precontrast without fat saturation, T1-weighted precontrast with fat saturation, and T1-weighted postcontrast images correlated with histopathologic findings in 12 of 15 vessels, eight of 10 vessels, and 14 of 16 vessels, respectively. Abnormal histopathologic findings included: arterial wall thickening (N = 3), arterial dissection (N = 2), focal fibrous plaque (N = 2), adherent thrombus (N = 1). The T1-weighted postcontrast images were not compromised by artifacts and had the highest score for vessel wall signal and conspicuity. T1-weighted precontrast images were compromised by chemical shift artifact and poor blood suppression. Negligible artifacts were created by the platinum stent.The T1-weighted fat saturated postcontrast pulse sequence was superior to other sequences for transvenous MR imaging of the arterial wall.

    View details for DOI 10.1097/01.RVI.0000092904.31640.BE

    View details for Web of Science ID 000185854100014

    View details for PubMedID 14551280

  • Transcatheter coil embolization of large pulmonary artery pseudoaneurysms in a child JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Liddell, R. P., Patel, S., Neuwirth, M., Hebert, J., Arepally, A., Hofmann, L. V. 2003; 14 (7): 923-927


    The authors report a case of a 5-year-old boy who initially presented with mastoiditis, underwent successful surgical treatment, and during the immediate postoperative period developed multiple, bilateral pulmonary artery pseudoaneurysms. The large size and multiplicity of the pseudoaneurysms precluded the patient from undergoing thoracic surgery. Successful endovascular coil and wire embolization was performed in a staged set of procedures with use of more than 30 m of wire and coils.

    View details for DOI 10.1097/01.RVI.0000082823.75926.05

    View details for Web of Science ID 000184102500013

    View details for PubMedID 12847201

  • Arteriographic and pathologic evaluation of two suture-mediated arterial closure devices in a porcine model JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Hofmann, L. V., Sood, S., Liddell, R. P., Gupta, A., Arepally, A., Rodriguez, E. R., Eng, J. 2003; 14 (6): 755-761


    To determine the acute and short-term effects the Sutura 8-F SuperStitch and Perclose 6-F Closer devices have on the femoral artery, as determined by angiography and pathologic examination.From a common carotid artery cutdown, eight pigs underwent pelvic angiography (i) before placement of bilateral common femoral artery vascular sheaths, (ii) after sheath insertion, and (iii) after device deployment. Two pigs were immediately killed; six survived 4 weeks for repeat angiography and vessel harvest.Average vessel diameter before sheath insertion was 5.9 mm +/- 0.6 and 5.8 mm +/- 0.6 for vessels with Perclose and Sutura devices, respectively. After deployment of the Sutura device, there was a 44.7% (P =.001) mean diameter reduction from preprocedural diameters, compared to a 59.3% reduction (P <.001) with the Perclose device. After deployment of the Sutura device, there was a mean vessel diameter reduction of 14.1% (P =.53) versus the diameter immediately after sheath placement. After deployment of the Perclose device, there was a mean vessel diameter reduction of 43.8% (P =.05) versus the diameter immediately after sheath placement. At 4-week angiography, all vessels returned to their original diameters before sheath insertion. Pathologic examination showed mild adventitial fibrosis creating a "fibrous hood" surrounding the suture and vessel.Despite significant luminal compromise after device deployment, all vessels appeared normal on angiography at 4 weeks. Contrary to the normal angiographic findings, both devices incited periadventitial fibrosis, which created a fibrous hood around the suture and vessel.

    View details for DOI 10.1097/01.RVI.0000079985.80153.17

    View details for Web of Science ID 000183625000009

    View details for PubMedID 12817043

  • An evaluation of commonly employed central venous catheter kits and their potential risk for complications of excess guidewire introduction JOURNAL OF CLINICAL ANESTHESIA Rufener, J. B., Andrews, R. T., Pfister, M. E., Hofmann, L. V., Bloch, R. D., Kudryk, B. T., Venbrux, A. C. 2003; 15 (4): 250-256


    To evaluate the components of commonly used central venous catheter kits with respect to the potential for guidewire-mediated complications during catheter placement.Prospective, nonrandomized, observational study.Six academic hospitals across the United States.None.None.30 commercially manufactured catheter kits (15 tunneled, 15 nontunneled) were opened and evaluated. The catheter or sheath to be introduced was measured and a corresponding ideal guidewire length was calculated. The ideal length was then compared to the actual length, and differences were tabulated. Wire tip configuration and the presence and pattern of distance markings were recorded and, in conjunction with the catheter and wire length discrepancies, were used to grade the relative risk of introducing excess guidewire during catheter placement. Of 30 kits evaluated, 14 (46.7%) had guidewires more than 20 cm longer than necessary. The mean excess wire length was 15 cm (range: 8 to 55 cm) and did not differ significantly between tunneled and nontunneled catheter kits. Only 10 kits (33.3%) had distance markings of any type, and there was no standardization among them; none corresponded to previously published recommendations. There was potential risk of excess wire introduction in 18 catheter kits, of which seven were nontunneled devices designed for bedside placement.The design of commonly employed central venous access catheter kits is such that there is a mismatch between guidewire and catheter length and a general lack of guidewire markings. We believe that these designs may predispose to the introduction of excess guidewire and result in guidewire-mediated complications during catheter placement. This risk can likely be reduced by matching the guidewires to the devices placed over them and by standardizing guidewire distance markings.

    View details for DOI 10.1016/S0952-8180(03)00060-6

    View details for PubMedID 12888159

  • Multidetector-row computed tomography with three-dimensional volume rendering of pancreatic cancer: A complete preoperative staging tool using computed tomography angiography and volume-rendered cholangiopancreatography JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Johnson, P. T., Heath, D. G., Hofmann, L. V., Horton, K. M., Fishman, E. K. 2003; 27 (3): 347-353


    Volume rendering, a postprocessing computer algorithm that creates three-dimensional (3D) displays from computed tomography (CT) datasets, can create 3D cholangiographic images (volume-rendered cholangiopancreatography, or VRCP) from intravenous contrast-enhanced abdominal CT datasets without the use of a biliary contrast agent. This article illustrates the utility of VRCP in the setting of biliary obstruction due to pancreatic cancer. The 3D renderings of the intra- and extrahepatic biliary tree provide valuable information for planning biliary drainage, including the location and length of the obstruction as well as the relationship of intrahepatic ducts to liver metastases.

    View details for Web of Science ID 000183746200008

    View details for PubMedID 12794597

  • The safety, efficacy, and pharmacoeconomics of low-dose alteplase compared with urokinase for catheter-directed thrombolysis of arterial and venous occlusions JOURNAL OF VASCULAR SURGERY Sugimoto, K., Hofmann, L. V., Razavi, M. K., Kee, S. T., Sze, D. Y., Dake, M. D., Semba, C. P. 2003; 37 (3): 512-517


    The purpose of this study was to compare the efficacy, complications, and costs associated with low-dose (<2 mg/h) alteplase (tissue plasminogen activator [t-PA]) versus urokinase for the catheter-directed treatment of acute peripheral arterial occlusive disease (PAO) and deep vein thrombosis (DVT).A retrospective review was performed during sequential time periods on two groups with involved extremities treated with either t-PA with subtherapeutic heparin (TPA group) or urokinase with full heparin (UK group) at a single center. Treatment group characteristics, success rates, complications, dosages, infusion time, and costs were compared.Eighty-nine patients with 93 involved limbs underwent treatment (54 with DVT, 39 with PAO). The treatment groups were statistically identical (TPA: 45 limbs; 24 with DVT, 53.3%; 21 with PAO, 46.7%; UK: 48 limbs; 30 with DVT, 62.5%; 18 with PAO, 37.5%). The overall average hourly infused dose, total dose, infusion time, success rates, and cost of thrombolytic agent were as follows (+/- standard deviation): TPA, 0.86 +/- 0.50 mg/h, 21.2 +/- 15.1 mg, 24.6 +/- 11.2 hours, 89.4%, $466 +/- $331; and UK, 13.5 +/- 5.6 (10(4)) U/h, 4.485 +/- 2.394 million U, 33.3 +/- 13.3 hours, 85.7%, $6871 +/- $3667, respectively. Major and minor complication rates were: TPA, 2.2% and 8.9%; and UK, 2.1% and 10.4%, respectively. No statistical differences in success rates or complications were observed; however, t-PA was significantly (P <.05) less expensive and faster than urokinase.Low-dose t-PA combined with subtherapeutic heparin is equally efficacious and safe compared with urokinase. Infusions with t-PA were significantly shorter and less expensive than those with urokinase.

    View details for DOI 10.1067/mva.2002.41

    View details for Web of Science ID 000181364400005

    View details for PubMedID 12618684

  • Treatment of splenic artery aneurysm with use of a stent-graft JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Arepally, A., Dagli, M., Hofmann, L. V., Kim, H. S., Cooper, M., Klein, A. 2002; 13 (6): 631-633

    View details for Web of Science ID 000176954800012

    View details for PubMedID 12050305

  • Weight-based rt-PA thrombolysis protocol for acute native arterial and bypass graft occlusions JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Arepally, A., Hofmann, L. V., Kim, H. S., Geschwind, J. F., Kirkwood, S., Oechsle, D., Perler, B. 2002; 13 (1): 45-50


    To determine technical success and complications with weight-adjusted dosing of recombinant tissue plasminogen activator (rt-PA) for arterial and bypass graft occlusions.During an 8-month period, prospective data were collected on patients undergoing catheter-directed thrombolysis. Retrospective review of all medical charts and blood bank data were performed for confirmation. All patients underwent a standard weight-adjusted protocol for catheter-directed thrombolysis. Thrombolytic therapy with rt-PA (0.2 mg/mL) was defined as low-dose when 0.02 mg/kg/h rt-PA was used and high-dose when 0.04 mg/kg/h of rt-PA was used. Low-dose heparin therapy was used. Total infusion time, total dose, and hourly rate of dose were calculated. Technical success, defined as complete removal of all clot without surgical intervention, complications, and frequency of transfusions were tabulated.A total of 35 patients underwent catheter-directed thrombolysis with rt-PA, including a total of 21 bypass grafts (60%) and 14 native arteries (40%). Mean age was 57 years (+/- 22.5; range, 3 mo to 83 y). Average rate of heparin infusion was 472.8 U/h (+/- 227). Success rates for graft thrombolysis were 90% (18 of 21). Success rates for native vessels were 79% (11 of 14). In patients who underwent only a low-dose protocol, the transfusion rate was 15% and major complications were 10%. In patients with a combined low-dose/high-dose administration, the transfusion rate was 46% and major complications were 13%. Overall success rate and major complication rates were 86% (30 of 35) and 11% (four of 35), respectively. Frequency of transfusions was 37% (13 of 35; mean, 2.8 U).Although weight-adjusted dosing for rt-PA provides a high efficacy of relieving ischemia, the rate of complications, especially bleeding, seems excessive in comparison to historical experience with urokinase. Administration of short-term high doses of rt-PA did not appear to have any beneficial effect. Further investigation with lower dosing and concentration should be considered.

    View details for Web of Science ID 000173425600006

    View details for PubMedID 11788694

  • GPIIb-IIIa receptor inhibitors: What the interventional radiologist needs to know CARDIOVASCULAR AND INTERVENTIONAL RADIOLOGY Hofmann, L. V., Razavi, M., Arepally, A., Reginelli, J. P., Resar, J., Geschwind, J. F., Corl, F. 2001; 24 (6): 361-367


    The glycoprotein IIb-IIIa (GPIIb-IIIa) receptor inhibitors have established themselves as first line therapy in the treatment of acute coronary syndromes (ACS) and percutaneous coronary intervention (PCI). The benefit of these agents rests in their ability to attenuate the deleterious effects of platelet activation, both at the site of an inflamed vessel wall (due to a ruptured plaque or PCI) and in the microcirculation as a result of embolization. Based on these results, interventional radiologists are beginning to explore the potential of using GPIIb-IIIa inhibitors during interventions in the peripheral circulation. This paper reviews the molecular biology of the GPIIb-IIIa receptor, the pharmacology of the GPIIb-IIIa receptor inhibitors, the current coronary and peripheral vascular literature as it pertains to the GPIIb-IIIa receptor inhibitors, and potential future applications of the GPIIb-IIIa receptor inhibitors in the peripheral circulation.

    View details for Web of Science ID 000173276400001

    View details for PubMedID 11907740

  • Tumor transport physiology: Implications for imaging and imaging-guided therapy 85th Annual Meeting and Scientific Assembly of the Radiological-Society-of-North-America (RSNA) Kuszyk, B. S., Corl, F. M., Franano, F. N., Bluemke, D. A., Hofmann, L. V., Fortmann, B. J., Fishman, E. K. AMER ROENTGEN RAY SOC. 2001: 747–53

    View details for Web of Science ID 000171144700002

    View details for PubMedID 11566666

  • Lymphoscintigraphy in the diagnosis of lymphatic leak after surgical repair of femoral artery injury CLINICAL NUCLEAR MEDICINE JONES, T. R., Carlisle, M. R., Hofmann, L. V., Strauss, H. W., Olcott, C. 2001; 26 (1): 14-17


    Technetium-99m-labeled sulfur colloid lymphoscintigraphy is useful to evaluate lower extremity lymphatic circulation in cases of possible lymphedema and to reveal abnormal lymphatic collections. Groin lymphatic fistulas and lymphoceles are known complications of peripheral vascular surgical procedures. The authors describe a patient with ascites that developed into right lower extremity swelling after surgical repair of a femoral artery injury. Even after surgical ligation of multiple lymphatic channels, the patient continued to have lymphorrhea. It was unclear whether this was attributable to a persistent lymphatic leak or an ascitic leak from a postsurgical defect resulting in an abnormal connection with the peritoneal cavity.Lymphoscintigraphy of the lower extremities was performed using Tc-99m sulfur colloid. Images were obtained at several intervals after injection of the radiotracer. Images were also acquired after the wound packing was removed.The images revealed an accumulation of radiotracer in the right groin, confirming the lower extremity lymphatic origin of the collection.Lymphoscintigraphy is useful to evaluate the origin of serous collections in the groin, a region in which lymphatic complications of vascular surgery are not uncommon.

    View details for Web of Science ID 000165887400004

    View details for PubMedID 11139046

  • Angioarchitecture of pulmonary arteriovenous malformations: Characterization using volume-rendered 3-D CT angiography CARDIOVASCULAR AND INTERVENTIONAL RADIOLOGY Hofmann, L. V., Kuszyk, B. S., Mitchell, S. E., Horton, K. M., Fishman, E. K. 2000; 23 (2): 165-170

    View details for Web of Science ID 000086437600018

    View details for PubMedID 10795848

  • Three-dimensional helical CT angiography in renal transplant recipients: A new problem-solving tool AMERICAN JOURNAL OF ROENTGENOLOGY Hofmann, L. V., Smith, P. A., Kuszyk, B. S., Kraus, E., Fishman, E. K. 1999; 173 (4): 1085-1089


    Our objective was to describe the use of three-dimensional helical CT angiography for the evaluation of renal transplant recipients presenting with hypertension, graft dysfunction, or both after transplantation by evaluating the native and transplanted renal arteries in a single examination.Early results indicate that three-dimensional helical CT angiography of renal transplant recipients presenting with hypertension, graft dysfunction, or both after transplantation yields valuable information that can be used to guide further therapy.

    View details for Web of Science ID 000082714900048

    View details for PubMedID 10511184

  • Epidermoid inclusion cysts seen on CT of a patient with Gardner's syndrome AMERICAN JOURNAL OF ROENTGENOLOGY Van Epps, K. J., Kuszyk, B. S., Hofmann, L. V., Fishman, E. K. 1999; 173 (3): 858-859

    View details for Web of Science ID 000082125100105

    View details for PubMedID 10470965

  • Utilization of computed tomography in patients hospitalized with community-acquired pneumonia. Maryland medical journal (Baltimore, Md. : 1985) Beall, D. P., Scott, W. W., Kuhlman, J. E., Hofmann, L. V., Moore, R. D., Mundy, L. M. 1998; 47 (4): 182-187


    The objective of the study was to assess the frequency of the use of chest computed tomography in 385 adults hospitalized with community-acquired pneumonia and determine whether the computed tomography examinations yielded additional diagnostic information. Also, if additional information was obtained, the study determined whether it changed the patient's treatment plan.

    View details for PubMedID 9709508

  • Thrombosis of the deep femoral vein: A potential pitfall of color flow duplex Doppler ultrasonography SOUTHERN MEDICAL JOURNAL Hofmann, L. V., Bluemke, D. A., Fishman, E. K. 1997; 90 (12): 1244-1247


    This case illustrates a potential pitfall of color flow duplex Doppler ultrasonography with compression in the evaluation of suspected deep venous thrombosis (DVT). Because of its low cost, accuracy, and noninvasiveness, ultrasonography is the appropriate first choice in the evaluation of suspected DVT, but there does exist the possibility of a false-negative examination. Magnetic resonance venography (MRV) should be reserved for cases in which there is a high clinical suspicion for DVT, as well as either morbid obesity that would limit the evaluation of deep pelvic and deep femoral veins or conflicting results of other imaging studies. All cases of suspected thrombosis, including those not adequately evaluated by ultrasonography, can be accurately assessed by MRV, which is not as invasive as standard venography.

    View details for Web of Science ID A1997YL06900018

    View details for PubMedID 9404915

  • The role of computed tomography in community-acquired pneumonia. Administrative radiology journal : AR Hofmann, L. V., Beall, D. P. 1997; 16 (6-7): 30-33

    View details for PubMedID 10170270

  • Medication-induced adynamic ileus. Maryland medical journal (Baltimore, Md. : 1985) Beall, D. P., Hofmann, L. V. 1996; 45 (5): 415-416

    View details for PubMedID 8935855