Klaus D Hagspiel

University of Virginia, Charlottesville, Virginia, United States

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Publications (235)517.17 Total impact

  • Lucia Flors, Patrick T Norton, Klaus D Hagspiel
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    ABSTRACT: We report a case of a glomuvenous malformation involving the dorsal aspect of the right hand and distal forearm in an 11-year-old boy. He had a history of multiple vascular anomalies since birth and presented with increasing right hand pain. MRI played an important role in characterizing and determining the extent of the lesion. In particular, dynamic time-resolved contrast-enhanced MR angiography precisely defined its vascularity. The diagnosis was made histopathologically after partial resection of the lesion. Glomuvenous malformation is a rare developmental hamartoma that originates from the glomus body. Clinically they usually resemble a venous malformation but they are a different entity. In the appropriate clinical setting this rare condition must be included in the differential diagnosis of a vascular malformation, especially when subtle arterial enhancement, early venous shunting and progressive filling of dilated venous spaces are depicted on MRA.
    Pediatric Radiology 07/2014; · 1.57 Impact Factor
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    ABSTRACT: ABSTRACT This study aimed to assess the efficacy of the radioprotector amifostine in limiting radiation toxicity in a rabbit model of lung stereotactic body radiation therapy (SBRT) by correlating contrast-enhanced magnetic resonance angiography (ce-MRA), computed tomography (CT), and helium-3 (He-3) magnetic resonance imaging (MRI) with histopathology. Multiple MRI techniques were tested to obtain complementing physiologic information. Thirteen rabbits received SBRT to the right lower lobe of the lung. Specifically, 4 received 3 × 11 Gray (Gy), 6 received 3 × 11 Gy and 50 mg/kg of amifostine pre-SRBT, and 3 received 3 × 7, 3 × 9, or 3 × 13 Gy. Imaging was performed at baseline and 4, 8, 12, and 16 weeks post-SBRT. Ce-MRA perfusion difference between lungs in the irradiated group at 16 weeks post-treatment was statistically significant (P = .04) whereas the difference in the irradiated + amifostine group was not (P = .30). Histologically observed low red blood cell (RBC) count and CT hypodensity suggests changes were primarily related to perfusion; however, structural changes, such as increased alveolar size, were also present. No changes in He-3 MRI lung ventilation were observed in either group. Although radiation-induced injury detected in rabbits as CT hypodensity contrasted with increased density observed in humans/rodents, the changes in ce-MRA and CT were still significantly reduced after the addition of amifostine to SBRT. Use of CT and selected MRI techniques helped to pinpoint primary physiologic changes.
    Experimental Lung Research 06/2014; · 1.47 Impact Factor
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    ABSTRACT: PurposeTo develop a spin echo train sequence with spiral readout gradients with improved artery–vein contrast for noncontrast angiography.TheoryVenous T2 becomes shorter as the echo spacing is increased in echo train sequences, improving contrast. Spiral acquisitions, due to their data collection efficiency, facilitate long echo spacings without increasing scan times.Methods Bloch equation simulations were performed to determine optimal sequence parameters, and the sequence was applied in five volunteers. In two volunteers, the sequence was performed with a range of echo times and echo spacings to compare with the theoretical contrast behavior. A Cartesian version of the sequence was used to compare contrast appearance with the spiral sequence. Additionally, spiral parallel imaging was optionally used to improve image resolution.ResultsIn vivo, artery–vein contrast properties followed the general shape predicted by simulations, and good results were obtained in all stations. Compared with a Cartesian implementation, the spiral sequence had superior artery–vein contrast, better spatial resolution (1.2 mm2 versus 1.5 mm2), and was acquired in less time (1.4 min versus 7.5 min).Conclusion The spiral spin echo train sequence can be used for flow-independent angiography to generate three-dimensional angiograms of the periphery quickly and without the use of contrast agents. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc.
    Magnetic Resonance in Medicine 04/2014; · 3.27 Impact Factor
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    ABSTRACT: To evaluate the diagnostic performance of dual-energy (DE) computed tomography (CT) after thoracic endovascular aortic repair (TEVAR) of type B dissection, and to investigate the value of late delayed (LD) acquisition in endoleak detection and false lumen patency assessment. Twenty-four patients with TEVAR for type B dissection underwent 53 tripe-phase CT examinations. Single-source unenhanced acquisition was followed by single-source arterial-phase and DE LD phase (300-s delay) imaging. Virtual noncontrast images were generated from DE acquisition. Two blinded radiologists retrospectively evaluated the cases in three reading sessions: session A (triphasic protocol), session B (virtual noncontrast and arterial phase), and session C (virtual noncontrast and arterial and LD phases). Endoleak detection accuracy during sessions B and C compared with session A (reference standard) was investigated. False lumen patency was assessed. Effective radiation dose was calculated. Session A revealed 37 endoleaks in 30 of 53 studies (56.6%). Session B revealed 31 of the 37 endoleaks, with one false-positive case, 83.8% sensitivity, 95.8% specificity, 79.3% negative predictive value, and 96.9% positive predictive value. Session C correctly depicted all 37 endoleaks, with one false-positive case, 100% sensitivity, 95.8% specificity, 100% negative predictive value, and 97.4% positive predictive value. Underestimation of false lumen patency was found in session B (P = .013). Virtual noncontrast imaging resulted in 17% radiation exposure reduction. Virtual noncontrast imaging can replace standard unenhanced images in follow-up after TEVAR of type B dissection, thus reducing radiation dose. Delayed-phase imaging is valuable in low-flow endoleaks detection and false lumen patency assessment.
    Journal of vascular and interventional radiology: JVIR 01/2014; · 1.81 Impact Factor
  • Conference Paper: Vascular Malformations
    Klaus D. Hagspiel
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    ABSTRACT: LEARNING OBJECTIVES 1) To review the classification of vascular malformations and tumors and their clinical and MRI features. 2) To review appropriate MR imaging protocols for the assessment and treatment follow up of these lesions. ABSTRACT Vascular malformations and tumors comprise a wide, heterogeneous spectrum of lesions that often represent a diagnostic and therapeutic challenge. Frequent use of an inaccurate nomenclature has led to considerable confusion. Since the treatment strategy depends on the type of vascular anomaly, correct diagnosis and classification are crucial. Magnetic resonance (MR) imaging is the most valuable modality for classification of vascular anomalies because it accurately demonstrates their extension and their anatomic relationship to adjacent structures. This presentation will review the clinical and MR imaging features that aid in diagnosis of vascular anomalies and their proper classification. MR imaging protocols suitable for comprehensive assessment of vascular anomalies including functional analysis of the involved vessels will be discussed.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: PURPOSE To compare the radiation dose and image quality of pediatric cardiac computed tomography angiography (CCTA) examinations using existing scan modes on dual source (DS) scanners. METHOD AND MATERIALS CCTA scans of 56 pediatric patients (age range 1d - 18yrs, mean 7.8±7.9 yrs) were reviewed retrospectively. Scans were performed on first or second generation DS CT systems. Scans were divided into 3 groups according to scan mode: retrospective ECG-gated helical (RETRO) (n=33), prospective ECG-triggered sequential (PRO) (n=8) and high-pitch spiral (FLASH) (n=15). The impact in radiation dose of automated dose-optimized selection of x-ray tube voltage (CARE kV), available in second generation DS scanner, was also assessed, relative to manual tube voltage selection in first generation DS. Size-specific dose estimate (SSDE) and effective dose were calculated. Image quality was assessed qualitatively by two radiologists on a 5 point Likert scale. RESULTS For RETRO scans, PRO scans and FLASH scans the mean effective dose values (mSv) were 3.90±2.98, 3.33±2.13, and 2.01±1.05 and mean SSDE values (mGy) were 13.90±9.52, 13.85±12.14, and 4.23±2.69. The differences in effective doses between RETRO and FLASH modes were statistically significant (p<0.04). For SSDE, differences between RETRO and FLASH and PRO and FLASH were significant (p<0.02). CARE kV was applied in 19 patients resulting in mean effective dose and SSDE of 2.10±1.04 mSV, 5.83±4.63 mGy versus 3.89±2.91 mSv and 13.90±10.29 mGy for the remaining 37 patients. For the effective dose and SSDE, the difference between scans with or without CARE kV was statistically significant (p<0.02). Average image quality scores were 4.45, 4.50 and 4.47 for RETRO, PRO, and FLASH, respectively; and 4.47 for scans with CARE kV and 4.46 for scans without. Pearson Χ2 revealed no difference in image quality based on the presence of CARE kV or based on the scan mode used. CONCLUSION Using high pitch spiral mode, low RD pediatric DS CCTA can be performed without sacrificing quality. The use of automated dose-optimized selection of kV resulted in the lowest doses. CLINICAL RELEVANCE/APPLICATION When using DS scanners for pediatric cardiac CTA, high pitch spiral mode and automatic kV selection should be employed to produce high quality examinations with the minimal radiation dose possible.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: OBJECTIVE. CT angiography using modern MDCT scanners has evolved into a highly accurate noninvasive diagnostic tool for the evaluation of patients with pathologic abnormalities of the upper extremity arterial system. CONCLUSION. Here we focus on the use of this modality in patients with nontraumatic vascular pathologic abnormalities.
    American Journal of Roentgenology 10/2013; 201(4):753-63. · 2.90 Impact Factor
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    ABSTRACT: OBJECTIVE. In this article, we focus on the vascular complications related to liver, pancreas, and kidney transplantation. CONCLUSION. Long term allograft survival of solid organ transplantation depends on early intervention of complications. Noninvasive imaging with ultrasound, CT, and MRI allows accurate diagnosis of complications and aids in treatment planning.
    American Journal of Roentgenology 10/2013; 201(4):W544-53. · 2.90 Impact Factor
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    ABSTRACT: OBJECTIVE. The objective of this article was to address 10 frequently asked questions that radiologists face when planning, performing, and interpreting an MRI study in a patient with a soft-tissue vascular anomaly. CONCLUSION. MRI permits a comprehensive assessment of vascular anomalies. It is important for radiologists to be familiar with the classification and correct nomenclature of vascular anomalies as well as the MRI protocol and distinct imaging findings of the different vascular malformations and tumors.
    American Journal of Roentgenology 10/2013; 201(4):W554-62. · 2.90 Impact Factor
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    ABSTRACT: OBJECTIVE. In this article, we focus on the arterial anatomy of the upper extremities, the technical aspects of upper extremity CT angiography (CTA), and CTA use in trauma patients. CONCLUSION. CTA using modern MDCT scanners has evolved into a highly accurate noninvasive diagnostic tool for the evaluation of patients with abnormalities of the upper extremity arterial system.
    American Journal of Roentgenology 10/2013; 201(4):745-52. · 2.90 Impact Factor
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    ABSTRACT: To develop and assess a three-dimensional refocused turbo spin-echo (rTSE) sequence for generating peripheral angiograms. This sequence combines the rapid T2 -weighting of TSE and the better flow performance of the fully-refocused gradients of balanced steady state free precession (bSSFP), along with bSSFP-style phase alternation of refocusing radiofrequency (RF) pulses. The signal behavior generated by such a sequence was explored through Bloch equation simulations. The rTSE and TSE sequences were both used to generate peripheral angiograms in nine normal volunteers. The signal to noise ratio, contrast resolution, and vessel sharpness of the resulting images were used as bases for comparison. Additionally, the rTSE sequence was applied in four patients with peripheral artery disease to preliminarily assess its efficacy in a clinical setting through quality scoring by two experienced radiologists. The rTSE's RF phase alternation approach out-performs a simple balanced-gradient CPMG (Carr-Purcell-Meiboom-Gill) -style TSE sequence in the presence of B0 and B1 inhomogeneities. In volunteers, the rTSE sequence yielded better arterial-venous contrast (0.378 ± 0.145 versus 0.155 ± 0.202; P < 0.01) and increased vessel sharpness (0.340 ± 0.034 versus 0.263 ± 0.034; P < 0.005) over TSE images. Stenoses visible in conventional angiographic images in patients were successfully imaged with the rTSE sequence; however, image quality scores in patients were lower than in volunteers (1.2 ± 0.38 versus 3.0 ± 1.0; P < 0.05). The rTSE sequence generates nonsubtractive, flow-independent, peripheral MR angiograms with better arterial-venous contrast and vessel sharpness in normal volunteers than a conventional TSE sequence.J. Magn. Reson. Imaging 2013. © 2013 Wiley Periodicals, Inc.
    Journal of Magnetic Resonance Imaging 09/2013; · 2.57 Impact Factor
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    ABSTRACT: Acute aortic syndromes and traumatic aortic injury are often diagnosed on CT angiography, possibly requiring emergent intervention. Advances in handheld computing have created the possibility of viewing full DICOM datasets from a remote location. We evaluated the ability to diagnose and characterize acute aortic pathologies on CT angiograms of the thorax using an iPhone-based DICOM viewer. This study was performed after Institutional Review Board approval. Fifteen CT angiograms of the thorax in suspected acute aortic syndromes were evaluated by three blinded radiologists on a handheld device using a DICOM viewer. Studies were evaluated for the ability to identify and classify aortic dissection, transection, or intramural hematoma, measure aortic dimensions, and identify mediastinal hematoma, arch variants, and pulmonary pathology. Studies were compared to blinded interpretations on a dedicated PACS workstation. The aortic pathology was correctly identified as aortic transection/pseudoaneurysm (n = 5), type A dissection (n = 2), and type A intramural hematoma (n = 1) by all reviewers, with no false-positive interpretations. This represents a sensitivity and specificity of 100 %. Mediastinal hematoma (n = 6), pneumothorax (five right, three left), and arch vessel involvement (n = 2) were identified in all cases. There was 88.5 % accuracy in identifying arch variants. Measurement of the size of the involved aortic segment was similar on handheld device and PACS workstation; however the adjacent normal aorta was 1.2 ± 1.0 mm larger on the handheld device (p = 0.03). Handheld DICOM viewers may be useful for emergent consultations and triage, and may expedite preprocedure planning to reduce the time interval between diagnostic scan and therapeutic intervention.
    Emergency Radiology 03/2013;
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    ABSTRACT: We are reporting our experience with imaging of vascular graft infections using computed tomography angiography (CTA), white blood cell (WBC) scintigraphy and software-based fusion imaging. Institutional review board approval was obtained. We performed a retrospective review of patients who had clinical signs and symptoms of vascular graft infection in whom both WBC single photon emission computed tomography (SPECT) and CTA was performed between 2005 and 2010. We performed fusion imaging with available data using software coregistration technique and analyzed outcome of the patients. We had 20 patients; 11 had grafts of the aorta, five had peripheral vascular grafts, three had aortic and peripheral vascular grafts, and one had a thoracic aortic graft. WBC imaging was positive in 10 patients, negative in six patients and indeterminate in 4 patients. CTA was positive in six patients, negative in four patients and indeterminate in 10 patients. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value (NPV) for WBC, CTA and WBC SPECT/CTA fusion were 75/100/80/100/50%, 88/50/80/88/50% and 94/50/85/88/67% respectively. The use of CTA, WBC scintigraphy, and image co-registration influenced the diagnostic confidence of graft infection and the outcome of the patients. Software-based fusion imaging of both modalities resulted in improved sensitivity, accuracy, and NPV.
    Clinical imaging 03/2013; 37(2):239-44. · 0.73 Impact Factor
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    ABSTRACT: The objective of our study was to evaluate the diagnostic performance of dual-source dual-energy CT (DECT) in the detection of endoleaks after thoracic endovascular aortic repair for thoracic aortic aneurysm and to investigate if a double-phase (arterial and dual-energy late delayed phase) or a single-phase (dual-energy late delayed phase) acquisition can replace the standard triphasic protocol. All DECT examinations performed for evaluation after thoracic endovascular aortic repair during a 30-month period were retrospectively reviewed. An initial single-source unenhanced acquisition was followed by a single-source arterial phase acquisition and a dual-energy 300-second late delayed phase acquisition. "Virtual noncontrast images" were generated from the dual-energy acquisition. Two independent and blinded radiologists evaluated the cases during three reading sessions: session A (triphasic protocol: standard unenhanced, arterial phase, and late delayed phase), session B (virtual noncontrast and late delayed phase), and session C (virtual noncontrast, arterial phase, and late delayed phase). The diagnostic accuracies of sessions B and C were calculated using session A as the reference standard. Contrast-to-noise ratios and effective radiation doses were calculated. Forty-eight patients (mean age, 66 years; age range, 19-84 years) underwent 74 triple-phase CT examinations. The single-phase studies (session B) were characterized by 85.7% sensitivity, 100% specificity, 100% negative predictive value (NPV), and 94.6% positive predictive value (PPV). The dual-phase study (session C) revealed 100% sensitivity, 100% specificity, 100% NPV, and 100% PPV. The use of the dual-phase protocol and single-phase protocol resulted in a radiation exposure reduction of 19.5% and 64.1%, respectively. Virtual noncontrast and late delayed phase images reconstructed from a single DECT acquisition can replace the standard triphasic protocol in follow-up examinations after thoracic endovascular aortic repair, thereby providing a significant dose reduction.
    American Journal of Roentgenology 02/2013; 200(2):451-60. · 2.90 Impact Factor
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    ABSTRACT: Nocardiosis is an infrequent but severe infection that primarily affects the lung and thence is able to produce disseminated disease. Prompt diagnosis of pulmonary and disseminated nocardiosis is of utmost importance in solid-organ transplant recipients to reduce mortality. Knowledge of the different radiological manifestations in the appropriate clinical setting is key to successful management of these patients. The aim of this review is to describe the radiological features of nocardiosis in immunosuppressed patients, particularly in solid-organ transplant recipients.
    Clinical Radiology 01/2013; · 1.66 Impact Factor
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    ABSTRACT: PURPOSE: This study was designed to describe the technique of arterial occlusion using a temporary occlusion balloon system as an alternative to coil occlusion during Yttrium-90 radioembolization of hepatic tumors. METHODS: Review of charts, angiography, and follow-up imaging studies of consecutive patients undergoing oncological embolization procedures in which a HyperForm system (ev3 Neurovascular, Irvine, CA) was used. Intraprocedural target vessel occlusion and patency of the target vessel on follow-up were recorded. Clinical data and Bremsstrahlung scans were reviewed for evidence of nontarget embolization. RESULTS: Four radioembolization procedures were performed in three patients (all female, age 48-54 (mean 52) years). Five arteries were temporarily occluded (three gastroduodenal arteries, one right gastric artery, and one cystic artery). All radioembolization procedures were successfully completed. Follow-up imaging (either digital subtraction angiography (DSA) or computed tomography angiography (CTA)) was available for all patients between 28-454 (mean 183) days following the procedure, demonstrating all five vessels to be patent. No clinical or imaging evidence for nontarget embolization was found. CONCLUSIONS: Temporary balloon occlusion of small and medium-sized arteries during radioembolization allows safe therapy with preserved postprocedural vessel patency on early and midterm follow-up.
    CardioVascular and Interventional Radiology 12/2012; · 2.09 Impact Factor
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    ABSTRACT: PURPOSE To evaluate the diagnostic performance of DE CT following endovascular repair of type B aortic dissection, and to investigate the value of a late delayed acquisition in the detection of endoleaks and assessment of the patency of the false lumen. METHOD AND MATERIALS In a 42-month period, 24 patients who had previously undergone endovascular repair of type B aortic dissection underwent 56 triple phase CT examinations. Initial single source unenhanced acquisition was followed by a single source arterial phase, and a DE late delayed (LD) phase performed 300 seconds after the administration of contrast material. Virtual noncontrast (VNC) images were generated from the DE acquisition. The cases were retrospectively evaluated by two independent and blinded radiologists in three different reading sessions: session A (triphasic protocol), session B (VNC and arterial phase) and session C (VNC, arterial and DE LD phase). Sensitivity, specificity, negative predictive values (NPV) and positive predictive values (PPV) for the detection of endoleaks during reading sessions B and C, as compared with the reference standard (reading session A), were calculated. Patency of the false lumen was assessed. Effective radiation dose was calculated. RESULTS Session A revealed 37 endoleaks in 30 of the 56 studies (53.6 %). Session B revealed correctly 31 of the 37 endoleaks, with one false positive case, and 83.8% sensitivity, 95.8 % specificity, 79.3% NPV, and 96.9% PPV. Session C depicted correctly all 37 endoleaks, with one false positive case and 100% sensitivity, 95.8% specificity, 100% NPV and 97.4% PPV. Underestimation of the patency of false lumen was found in session B (p=0.013). The use of the dual phase protocol resulted in a reduction in radiation exposure of 17%. CONCLUSION VNC can replace the standard unenhanced images in follow-up examinations after endovascular repair of type B aortic dissection. Delayed phase is valuable in the detection of low flow endoleaks and assessment of patency of false lumen. CLINICAL RELEVANCE/APPLICATION DE CT allows to reduce radiation dose which is particularly important in patients after endovascular repair of aortic dissection that undergo lifelong imaging surveillance with multiphase acquisitions.
    Radiological Society of North America 2012 Scientific Assembly and Annual Meeting; 11/2012
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    ABSTRACT: Gadolinium-enhanced magnetic resonance angiography allows rapid evaluation of the vascular structures of the thoracic outlet both in the neutral position and in abduction during one examination within FDA-approved dose limitations for contrast agents. The technique appears to be a good screening one for patients suspected of having vascular thoracic outlet syndrome.
    CardioVascular and Interventional Radiology 04/2012; 23(2):152-4. · 2.14 Impact Factor
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    ABSTRACT: Three patients with either a history of severe allergic reactions to iodinated contrast or marked renal insufficiency underwent interventional uroradiologic procedures using full-strength gadodiamide (Gd) as a contrast agent in place of iodinated contrast material. The procedures were percutaneous access for nephrostolithotomy, antegrade pyelography with placement of a nephroureteral stent, and a diagnostic nephrostogram with exchange of a nephroureteral stent. Gd was visualized fluoroscopically and produced satisfactory digital radiographs without allergic reaction or worsening renal function. Gd can be useful in guiding interventional uroradiologic procedures when iodinated contrast material is contraindicated.
    CardioVascular and Interventional Radiology 04/2012; 23(1):72-5. · 2.14 Impact Factor
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    ABSTRACT: Vascular complications after pancreatic transplantation carry a high rate of graft loss. Endovascular management of these complications is confined to stent placement for iliac artery inflow disease and embolization for arteriovenous fistulae (AVFs), pseudoaneurysms, or active bleeding. The current study describes the endovascular management of pancreatic transplant venous thrombosis (N = 1), arterial stenosis (N = 5), thrombosis (N = 3), pseudoaneurysms (N = 1), and AVF (N = 2). In addition, embolization of nonfunctioning grafts is described as an endovascular alternative to pancreatectomy.
    Vascular and Endovascular Surgery 04/2012; 46(3):262-8. · 0.88 Impact Factor

Publication Stats

2k Citations
517.17 Total Impact Points


  • 1999–2014
    • University of Virginia
      • • Department of Radiology and Medical Imaging
      • • Department of Surgery
      Charlottesville, Virginia, United States
  • 2011
    • Haydarpasa Numune Research and Teaching Hospital
      İstanbul, Istanbul, Turkey
    • Georgetown University
      • Department of Biostatistics, Bioinformatics, and Biomathematics
      Washington, Washington, D.C., United States
  • 2008–2011
    • Robert Wood Johnson University Hospital
      New Brunswick, New Jersey, United States
  • 2008–2010
    • Virginia Department of Health
      Richmond, Virginia, United States
  • 2009
    • Emory University
      • Department of Biomedical Engineering
      Atlanta, GA, United States
    • Vascular and Interventional Radiology
      Chicago, Illinois, United States
  • 2007
    • The University of Tennessee Health Science Center
      Memphis, Tennessee, United States
    • The Children's Hospital of Philadelphia
      • Department of Radiology
      Philadelphia, PA, United States
  • 2000
    • Royal College of Surgeons in Ireland
      Dublin, Leinster, Ireland