Meta-analysis of Intraprocedural Comparative Effectiveness of Vascular Plugs Vs Coils in Proximal Splenic Artery Embolization and Associated Patient Radiation Exposure.

PURPOSE: To compare vascular plugs to coil embolization of the proximal splenic artery and evaluate differences in radiation exposure to the patients. METHODS: An electronic literature search was performed for relevant studies from January 2000 to July 2018 that compared the efficacy of vascular plugs vs coils in splenic artery embolization. Only studies that investigated coil or vascular plug use, without combination with other embolic agents, were included. Meta-analysis was performed using a fixed effects model approach with the inverse variance-weighted average method to determine pooled differences in time to vessel occlusion, procedure time, fluoroscopy time, total number of devices used, and radiation exposure. Heterogeneity was assessed using the I square statistic. Pooled outcomes were compared, and quality assessments were evaluated using the Newcastle Ottawa Scale. RESULTS: Eight studies met inclusion criteria. 81 patients were embolized with vascular plugs and 52 patients with coils only. The most common indication for splenic artery embolization was trauma. Time to vessel occlusion was shorter in the vascular plug group by 7.11 minutes (P = 0.003). Fluoroscopy time was shorter by 13.82 minutes in the vascular plug cohort, and these patients received less radiation (-439 mGy) compared to the coil group (P = 0.006 and P = 0.02, respectively). The number of devices was significantly fewer in the vascular plug group (-3.54; P < 0.001). Procedure time was not statistically significant. CONCLUSION: Our data supports the vascular plug is superior to coils for embolization of the proximal splenic artery with respect to occlusion time, fluoroscopy time, patient radiation exposure, and number occlusive devices used.

The resuscitative endovascular balloon occlusion of aorta (REBOA) device-what radiologists need to know.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a novel device approved by the Food and Drug administration (FDA) in 2017 as an alternative to resuscitative emergent thoracotomy (RET). Due to advancements in placement of REBOA, including newly validated placement using anatomic landmarks, REBOA is now widely used by interventional radiologists and emergency physicians in acute subdiaphragmatic hemorrhage. Increased use of REBOA necessitates that radiologists are familiar with verification of proper REBOA placement to minimize complications. This review describes the REBOA device, indications, placement, and complications, summarizing the current available literature.

Selection of PD1/PD-L1 X-Aptamers.

Specific, chemically modified aptamers (X-Aptamers) were identified against two immune checkpoint proteins, recombinant Programmed Death 1 (PD-1) and Programmed Death Ligand 1 (PD-L1). Selections were performed using a bead-based X-Aptamer (XA) library containing several different amino acid functional groups attached to dU at the 5-position. The binding affinities and specificities of the selected XA-PD1 and XA-PDL1 were validated by hPD-1 and hPD-L1 expression cells, as well as by binding to human pancreatic ductal adenocarcinoma tissue. The selected PD1 and PDL1 XAs can mimic antibody functions in in vitro assays.

Ethnic and Gender Diversity in Radiology Fellowships.

PURPOSE: The purpose of the study is to assess ethnic and gender diversity in US radiology fellowship programs from 2006 to 2013. MATERIALS AND METHODS: Data for this study was obtained from Journal of the American Medical Association supplements publications from 2005 to 2006 to 2012-2013 (Gonzalez-Moreno, Innov Manag Policy Pract. 15(2):149, 2013; Nivet, Acad Med. 86(12):1487-9, 2011; Reede, Health Aff. 22(4):91-3, 2003; Chapman et al., Radiology 270(1):232-40, 2014; Getto, 2005; Rivo and Satcher, JAMA 270(9):1074-8, 1993; Schwartz et al., Otolaryngol Head Neck Surg. 149(1):71-6, 2013; Simon, Clin Orthop Relat Res. 360:253-9, 1999) and the US census 2010. For each year, Fisher's exact test was used to compare the percentage of women and under-represented minorities in each Accreditation Council for Graduate Medical Education (ACGME)-certified radiology fellowship to the percentage of women and under-represented minorities in (1) all ACGME-certified radiology fellowships combined, (2) radiology residents, (3) ACGME-certified fellows in all of medicine combined, (4) ACGME-certified residents in all of medicine combined, and (5) graduating medical students. Chi-Squared test was used to compare the percentage of women and under-represented minorities and the 2010 US census. RESULTS: p < 0.05 was used as indicator of significance. Interventional radiology and neuroradiology demonstrated the highest levels of disparities, compared to every level of medical education. Abdominal and musculoskeletal radiology fellowships demonstrated disparity patterns consistent with lack of female and URM medical graduates entering into radiology residency. CONCLUSION: All radiology fellowships demonstrated variable levels of gender and ethnic disparities. Outreach efforts, pipeline programs, and mentoring may be helpful in addressing this issue.

Percutaneous ultrasound guided implantation of VX2 for creation of a rabbit hepatic tumor model.

Creation of a VX2 tumor model has traditionally required a laparotomy and surgical implantation of tumor fragments. Open surgical procedures are invasive and require long procedure times and recovery that can result in post-operative morbidity and mortality. The purpose of this study is to report the results of a percutaneous ultrasound guided method for creation of a VX2 model in rabbit livers. A total of 27 New Zealand white rabbits underwent a percutaneous ultrasound guided approach, where a VX2 tumor fragment was implanted in the liver. Magnetic resonance imaging was used to assess for tumor growth and necropsy was performed to determine rates of tract seeding and metastatic disease. Ultrasound guided tumor implantation was successful in all 27 rabbits. One rabbit died 2 days following the implantation procedure. Two rabbits had no tumors seen on follow-up imaging. Therefore, tumor development was seen in 24/26 (92%) rabbits. During the follow-up period, tract seeding was seen in 8% of rabbits and 38% had extra-hepatic metastatic disease. Therefore, percutaneous ultrasound guided tumor implantation safely provides reliable tumor growth for establishing hepatic VX2 tumors in a rabbit model with decreased rates of tract seeding, compared to previously reported methods.

Multimodality imaging to assess immediate response to irreversible electroporation in a rat liver tumor model.

PURPOSE: To compare changes on ultrasonographic (US), computed tomographic (CT), and magnetic resonance (MR) images after irreversible electroporation (IRE) ablation of liver and tumor tissues in a rodent hepatoma model. MATERIALS AND METHODS: Studies received approval from the institutional animal care and use committee. Forty-eight rats were used, and N1-S1 tumors were implanted in 24. Rats were divided into groups and allocated for studies with each modality. Imaging was performed in normal liver tissues and tumors before and after IRE. MR imaging was performed in one group before and after IRE after hepatic vessel ligation. US images were graded to determine echogenicity changes, CT attenuation was measured (in Hounsfield units), and MR imaging signal-to-noise ratio (SNR) was measured before and after IRE. Student t test was used to compare attenuation and SNR measurements before and after IRE (P < .05 indicated a significant difference). RESULTS: IRE ablation produced greater alterations to echogenicity in normal tissues than in tumors. Attenuation in ablated liver tissues was reduced compared with that in control tissues (P < .001), while small attenuation differences between ablated (42.11 HU ± 2.11) and control (45.14 HU ± 2.64) tumors trended toward significance (P = .052). SNR in ablated normal tissues was significantly altered after IRE (T1-weighted images: pre-IRE, 145.95 ± 24.32; post-IRE, 97.80 ± 18.03; P = .004; T2-weighted images, pre-IRE, 47.37 ± 18.31; post-IRE, 90.88 ± 37.15; P = .023). In tumors, SNR differences before and after IRE were not significant. No post-IRE signal changes were observed after hepatic vessel ligation. CONCLUSION: IRE induces rapid changes on gray-scale US, unenhanced CT, and MR images. These changes are readily visible and may assist a performing physician to delineate ablation zones from the unablated surrounding parenchyma.

Endovascular treatment of intimomedial mucoid degeneration.

Intimomedial degeneration is a rare and poorly understood vascular disorder involving the circumferential deposition of large amounts of mucoid material within the intima and media of the arterial wall, causing weakening that results in aneurysm formation of the involved segment. The cause of the disease is unknown at this time. The authors describe the endovascular treatment of a large symptomatic superior gluteal artery aneurysm in a patient with multiple arterial aneurysms and the histologic diagnosis of intimomedial mucoid degeneration. In addition, they perform a review of the literature on this unusual vasculopathy.

Right ventricular migration and endovascular removal of an inferior vena cava filter.

A G2 inferior vena cava (IVC) filter was discovered in the right ventricle of an asymptomatic patient 3 months after placement. The present report describes an endovascular approach to remove the filter with use of two 35-mm Amplatz Goose Neck snares while the patient's cardiac rhythm was monitored and controlled by a cardiothoracic anesthesiologist.

A case of pancreatic islet cell transplantation in a patient with situs ambiguous: anatomical and radiological considerations.

Pancreatic islet cell transplantation is an evolving treatment of severe, refractory type 1 diabetes that has been gaining more use, particularly after one year rates of insulin independence post-transplantation were found to approach 80% under the Edmonton protocol. Islet cell transplantation involves percutaneous delivery of harvested allogeneic ß cells into the portal venous circulation for implantation into the liver. We present the case of a 35-year-old woman with type 1 diabetes and situs ambiguous with left isomerism and resultant variant anatomy of her portal venous anatomy who underwent islet cell transplantation, which, to our knowledge, has not been previously reported.

Covered stent treatment of carotid blowout syndrome.

Carotid artery blowout is a devastating complication of head and neck malignancy, irradiation, and trauma. New endovascular therapies of acute carotid artery rupture involve stent-directed, carotid-sparing treatment strategies. We report a case of successful covered stent treatment of carotid artery hemorrhage in the setting of head and neck cancer and review the literature describing the use of this therapeutic method. Evaluation of 19 recently reported cases of covered stent treatment of carotid artery blowout due to head and neck cancer and presenting with sentinel or acute hemorrhage demonstrates that this method is a fast and effective means of controlling bleeding, with a technical success rate of ~95%. A significant early recurrent hemorrhage rate raises concern regarding the short-term safety and efficacy of this therapy, however, and suggests that stent graft treatment of carotid artery rupture due to head and neck malignancy is best suited as a temporizing measure before more definitive therapy.

Use of a hydrogel-coated self-expandable coil to salvage a failed transcatheter embolization of a mesenteric hemorrhage.

HydroCoil (MicroVention, Aliso Viejo, CA, USA) is a self-expanding detachable coil developed to improve the endovascular occlusion of intracranial aneurysms. The hydrogel polymer covering the microcoil expands to several times its original diameter to enhance thrombosis of the intended vessel. We made use of this new technology to occlude a mesenteric artery pseudoaneurysm that failed superselective embolization with standard microcoils.