A Pilot First-in-Human Study of Embrace,a Polyethylene Glycol-Based Liquid Embolic Agent,in the Embolization of Malignant and Benign Hypervascular Tumors

PurposeTo investigate the safety and efficacy of an aqueous polyethylene glycol-based liquid embolic agent, Embrace Hydrogel Embolic System (HES), in the treatment of benign and malignant hypervascular tumors.Materials and MethodsA prospective, single-arm, multicenter study included 8 patients, 5 males and 3 females, with a median age of 58.5 years (30–85 years), who underwent embolization in 8 tumors between October 2019 and May 2020. Technical success was defined as successful delivery of HES to the index vessel, with disappearance of >90% of the targeted vascular enhancement or, for portal vein embolization, occlusion of the portal branches to the liver segments for future resection. The volume of HES administered, ease of use (5 point Likert scale), administration time, and adverse events (AEs) were recorded. Evaluation was performed at 7, 30, and 90 days via clinical assessment and blood testing, and follow-up imaging was performed at 30 days.ResultsEight patients were enrolled, and 10 embolizations were performed in 8 lesions. Tumors included hepatocellular carcinoma (n = 4), renal angiomyolipoma (n = 3), and intrahepatic cholangiocarcinoma (n = 1). Technical success was 100%, and the average ease of use was 3.3 ± 1.0 SD. The HES delivery time was 1–28 minutes (median, 16.5 minutes), and the HES volume injected was 0.4–4.0 mL (median, 1.3 mL). All patients reached 30-day follow-up with imaging, and 6 patients reached 90-day follow-up. There were 3 serious AEs in 2 patients that were unrelated to the embolic agent.ConclusionHES resulted in a 100% embolization technical success rate. The product ease of use was acceptable, and no target vessel recanalization was noted on follow-up imaging at 30 days.     

Biodegradable Polydioxanone Microspheres for Transcatheter Arterial Embolization: Proof of Principle

PurposeTo evaluate feasibility, embolization success, biodegradability, reperfusion, and biocompatibility of biodegradable microspheres (MS) made from polydioxanone (PDO) for transcatheter arterial embolization.Materials and MethodsUnilateral selective renal embolization of a segmental artery was performed in 16 New Zealand White rabbits with PDO-MS (100–150 μm and 90–315 μm). Animals were randomly assigned to different observation periods and underwent control digital subtraction angiography (DSA) and MR imaging immediately (n = 3), 1 week (n = 2), 4 weeks (n = 2), 8 weeks (n = 2), 12 weeks (n = 5), and 16 weeks (n = 2) after embolization. Kidneys were harvested for macroscopic and histologic analysis of embolization success, biodegradability, and biocompatibility.ResultsEmbolization was technically successful in 15 of 16 animals. One animal died of anesthesia-related circulatory failure. The 100–150 μm MS were injected easily through 3-F catheters; the 90–315 μm MS tended to clog with intermittent catheter obstruction. DSA and MR imaging showed successful target embolization in 13 of 15 animals. In 2 animals, the entire kidney was affected owing to catheter clogging, including a reflux of MS while flushing. Control DSA and MR imaging showed increasing vascular reperfusion with time. Macroscopic and histologic analysis revealed necrosis/infarction in areas in which embolization was achieved. MS were extensively degraded after 16 weeks, and overall inflammatory reaction was mild.ConclusionsBiodegradable PDO-MS induced effective embolization of target vessels while demonstrating good biocompatibility. MS increasingly dissolved at 16 weeks, partial reperfusion started at week 1, and complete reperfusion started at week 8, thus offering possible advantages as a temporary embolic agent.     

Treatment Outcomes of Embolization for Peripheral Arteriovenous Malformations

PurposeTo evaluate treatment outcomes of embolization for peripheral arteriovenous malformations (AVMs) in a tertiary referral center where ethanol is the primary agent of choice.MethodsA retrospective study was performed of 93 patients (median age, 31 years; range, 2–66 years) with peripheral AVMs treated with embolization (n = 442; median, 2 per patient; range, 1–82) between January 2010 and July 2016. Ethanol was used in most cases (n = 428; 97%). AVMs were classified as type I (n = 3), type II (n = 57), type IIIa (n = 5), type IIIb (n = 15), and type IV (n = 13) according to the Yakes classification system. Effectiveness of embolization was based on AVM devascularization on angiography: 100% (total), 90%–99% (near-total), 70%–90% (substantial), 30%–70% (partial), and 0%–30% (failure). Complications were graded according to the Society of Interventional Radiology classification.ResultsIn 69% of patients, 70%–100% devascularization was achieved. Total and near-total occlusion of the nidus were more often achieved in AVMs of types I and IIIa (both 100%) than in AVMs of types II, IIIb, and IV (56%, 67%, and 39%, respectively; P = .019). A total of 109 complications were identified: 101 minor (22.9%) and 8 major (1.8%). Major complications included wounds (n = 5), false aneurysm (n = 1), finger contracture (n = 1), and severe pain (n = 1) requiring therapy. The patient complication risk was significantly affected by the number of procedures (relative risk = 2.0; P < .001). Age, AVM location, and angioarchitecture type did not significantly affect complication risk.ConclusionsAVM embolization resulted in 70%–100% devascularization in 69% of patients, with few major complications. This study indicates that the type of AVM angioarchitecture affects the number of procedures needed and the achievability of AVM devascularization.     

Endovascular Therapy for Vasculogenic Erectile Dysfunction: A Systematic Review and Meta-Analysis of Arterial and Venous Therapies

PurposeTo systematically review and perform a meta-analysis on the safety and efficacy of endovascular therapy in the treatment of the two most common etiologies of vasculogenic erectile dysfunction (ED): veno-occlusive dysfunction (VOD) and arterial insufficiency (AI).Materials and MethodsPubMed, Web of Science, ScienceDirect, and Scopus databases were searched for published English literature regarding endovascular ED treatments. Case series (n ≥ 3) were included. Multiple data points were obtained, including demographic data, etiology, diagnosis method, imaging studies, treatment approach, technical success, clinical success, complications, and follow-up.ResultsSixteen relevant articles were obtained and a total of 212 patients with VOD and 162 with AI were identified. The VOD cohort were treated either percutaneously (60.4%; n = 128) or after surgical exposure of the deep dorsal vein (33.5%, n = 71), or it was unspecified (6.1%; n = 13). The most common embolic used was n-butyl cyanoacrylate (51.9%; n = 109). Meta-analysis found an overall clinical success rate of 59.8% in VOD patients. Complications occurred in 5.2% of patients (n = 11), with 9 considered to be mild and 2 considered to be severe. The AI cohort contained 162 patients most commonly treated via stenting of the internal pudendal artery (40.1%; n = 65). Meta-analysis found an overall clinical success rate of 63.2% in AI patients. Complications occurred in 4.9% of patients (n = 8), with 4 considered to be mild and 4 considered to be severe.ConclusionsEndovascular therapy for medically refractory ED is safe and may provide a treatment alternative to more invasive surgical management; however, conclusions are limited by the heterogeneity of clinical success definitions among the included studies.     

Where Have All the Punctures Gone? An Analysis of Thoracic Duct Embolizations

PurposeTo determine how frequently and how severely intra-abdominal structures are affected by transabdominal thoracic duct embolization (TDE).Materials and MethodsThirty-five TDE procedures in 35 patients (22 male; mean age, 57 y; age range, 10–79 y) with therapy-refractory chylous effusions were evaluated in which radiopaque embolization material outlined the access route on postinterventional CT. CT data were analyzed by 2 TDE-experienced radiologists. Abdominal structures and organs transgressed by the access route were recorded, and findings were correlated with clinical postinterventional course with follow-up of at least 44 days.ResultsIntra-abdominal structures/organs transgressed most often by the access route were the liver (n = 28), crus of the diaphragm (n = 25), pancreas (n = 14), portal vein (n = 10), duodenum (n = 7), inferior vena cava (n = 5), colon (n = 3), left renal vein (n = 2), pleura (n = 2), pericardium (n = 2), and gastric sleeve (n = 2). Pancreatitis was observed in 1 of 14 patients after pancreatic transgression. One case of clinically occult pulmonary glue migration occurred on catheter pullback through the left renal vein. Biliary peritonitis was observed after gallbladder puncture, necessitating cholecystectomy in 1 of 2 transbiliary punctures. No other relevant procedure-related complications such as hemorrhages or infectious complications were observed.ConclusionsDespite transgression of intra-abdominal structures, puncture- and access-related complications of TDE are rare. Transpancreatic manipulations are reasonably well tolerated.     

Outcome and Distal Access Patency in Subintimal Arterial Flossing with Antegrade-Retrograde Intervention for Chronic Total Occlusions in Lower Extremity Critical Limb Ischemia

PurposeTo report the outcome and distal access patency of the Subintimal Arterial Flossing with Antegrade-Retrograde Intervention (SAFARI) technique for chronic total occlusion (CTO) in critical limb ischemia (CLI).Materials and MethodsFrom January 2009 to June 2015, 220 SAFARI procedures were performed for 200 limbs in 191 patients (108 males [56.5%]; median age, 70 years old; range, 36 to 97 years old) with CLI (9.4% were Fontaine classification 3; and 90.6% were Fontaine classification 4). Distal access was obtained from the distal superficial femoral artery (n = 6), popliteal artery (n = 49), anterior tibial artery (n = 56), dorsalis pedis (n = 51), peroneal artery (n = 12), posterior tibial artery (n = 45), and lateral plantar artery (n = 1). Distal access hemostasis was obtained with internal balloon tamponade in 71.4% (n = 157). Outcome measurements were technical success, freedom from major amputation and complications. Preprocedural angiograms of clinically driven repeat interventions were reviewed in 73 cases for distal access patency.ResultsTechnical success was achieved in 80.5% (n = 177). Reasons for technical failure include inability to obtain distal access (n = 3), cross the occlusion retrogradely (n = 16), re-enter the true lumen (n = 9), and achieve antegrade blood flow after the procedure (n = 15). Freedom from major amputation for technically successful procedures was 84.7%, 82.9%, and 81.9% at 6, 12, and 24 months, respectively. There were 3 cases of distal access bleeding with 1case that required coil embolization. The distal access remained patent in 80.8% of observable cases with repeated endovascular intervention.ConclusionsDistal retrograde arterial access (SAFARI) technique is safe and effective in the treatment of CTOs in the context of CLI, after failure of antegrade revascularization.     

Strain Ultrasound Elastography of Aneurysm Sac Content after Randomized Endoleak Embolization with Sclerosing vs. Non-sclerosing Chitosan-based Hydrogels in a Canine Model

PurposeTo compare the mechanical properties of aneurysm content after endoleak embolization with a chitosan hydrogel (CH) with that with a chitosan hydrogel with sodium tetradecyl sulfate (CH-STS) using strain ultrasound elastography (SUE).Materials and MethodsBilateral common iliac artery type Ia endoleaks were created in 9 dogs. Per animal, 1 endoleak was randomized to blinded embolization with CH, and the other, with CH-STS. Brightness-mode ultrasound, Doppler ultrasound, SUE radiofrequency ultrasound, and computed tomography were performed for up to 6 months until sacrifice. Radiologic and histopathologic studies were coregistered to identify 3 regions of interest: the embolic agent, intraluminal thrombus (ILT), and aneurysm sac. SUE segmentations were performed by 2 blinded independent observers. The maximum axial strain (MAS) was the primary outcome. Statistical analysis was performed using the Fisher exact test, multivariable linear mixed-effects models, and intraclass correlation coefficients (ICCs).ResultsResidual endoleaks were identified in 7 of 9 (78%) and 4 of 9 (44%) aneurysms embolized with CH and CH-STS, respectively (P = .3348). CH-STS had a 66% lower MAS (P < .001) than CH. The ILT had a 37% lower MAS (P = .01) than CH and a 77% greater MAS (P = .079) than CH-STS. There was no significant difference in ILT between treatments. The aneurysm sacs embolized with CH-STS had a 29% lower MAS (P < .001) than those embolized with CH. Residual endoleak was associated with a 53% greater MAS (P < .001). The ICC for MAS was 0.807 (95% confidence interval: 0.754–0.849) between segmentations.ConclusionsCH-STS confers stiffer intraluminal properties to embolized aneurysms. Persistent endoleaks are associated with increased sac strain, an observation that may help guide management.     

Clinical Results of Distal Embolization in Grade V Splenic Injury: Four-Year Experience from a Single Regional Trauma Center

PurposeTo evaluate the benefits and risks of splenic artery embolization (SAE) in patients with American Association for the Surgery of Trauma (AAST) grade V blunt spleen injury (BSI)Materials and MethodsMedical records of 88 patients treated with SAE between April 2013 and May 2017 at a regional trauma care center were reviewed retrospectively. The BSI grade according to the AAST spleen injury scale (revised version 2018) was determined by using computed tomography (CT) images. A total of 42 patients (46.6%) had AAST grade V injury and were included in the analysis. Patient demographics, angiographic findings, embolization techniques, and technical and clinical outcomes, including splenic salvage rate and procedure-related complications, were examined.ResultsSAE was performed within 2 hours after admission for 78.5% of the patients. All patients underwent selective distal embolization (n = 42). Primary clinical success rate was 80.9% (n = 34), and secondary clinical success rate was 88.1% (n = 37). The clinical failure group consisted of 5 patients. Four patients underwent splenectomy, and 1 patient died due to acute respiratory distress syndrome after embolization. The splenic salvage rate was 85.7% (n = 36). No patient had sepsis at follow-up (median, 247.0 days; interquartile range, 92.0–688.0). Clinical success rates (P = .356) and spleen salvage rates (P = .197) of patients who were hemodynamically stable (n = 19) showed no significant differences from those who were unstable (n = 23).ConclusionsDistal embolization of grade V BSI is a safe and feasible procedure which is effective for successful spleen salvage.     

Superior Rectal Artery Embolization with Tris-Acryl Gelatin Microspheres: A Randomized Comparison of Particle Size

PurposeTo evaluate the safety and efficacy of superior rectal artery embolization (SRAE) with different-sized tris-acryl gelatin microspheres in symptomatic hemorrhoidal disease (HD).Materials and MethodsForty-two patients (male, 30; female, 12; median age, 45 years) with symptomatic HD (2 grade I, 8 grade II, 17 grade III, and 15 grade IV) were divided into 3 experimental arms (500–700 μm, 700–900 μm, and 900–1,200 μm groups; each had 14 patients) in a prospective randomized style to perform SRAE. Follow-up was performed by rectoscopy, clinical examination, and questionnaires. The primary outcome measure was the clinical success rate at 12 months. Secondary outcome measures were technical success rate, recurrence rate, procedure-related mortality, procedure-related complications, and any outcome changes between particle sizes.ResultsNo procedure-related deaths or major morbidities were observed. There was a 54% minor complication rate (n = 23/42) in the treated zone: 45% sustained small superficial ulcerations (n = 19/42), 7% small rectosigmoid junction ulcerations (n = 3/42), and 2% small fibrotic scar tissue (n = 1/42). The clinical success rate was 93%. Of the groups, the best French bleeding score decrease was obtained in the 900–1,200 μm group. There were improvements in the quality of life score and visual analogue scale score after the SRAE procedure, although not in the Goligher score. No recurrent disease was observed.ConclusionsSRAE with tris-acryl gelatin microspheres for symptomatic HD is a safe and efficient treatment, with results favoring the use of larger microspheres.     

Distal Radial Artery Access for Noncoronary Endovascular Treatment Is a Safe and Feasible Technique

PurposeTo evaluate safety and feasibility of distal radial artery (DRA) access for noncoronary interventional radiology procedures.Materials and MethodsAll interventional radiology procedures by means of DRA puncture from July 2017 to August 2018 were retrospectively reviewed. Eighty-two punctures in 56 patients were included, mostly in male patients (84% vs 16%). Mean age was 67.8 years (range, 33.3–87.3 years); mean height was 172 cm (range, 142–190 cm); and mean weight was 83 kg (range, 43–120 kg). Procedural characteristics, technical success, and complication rates were gathered from the medical records and follow-up ultrasound when available. Prerequisites for DRA access were adequate radioulnar collateral circulation, sufficient radial artery diameter, and informed consent in patients initially intended for conventional transradial access.ResultsProcedures included transarterial chemoembolization (n = 34), yittrium-90 pretreatment angiography (n = 21), yittrium-90 administration (transarterial radioembolization; n = 20), and embolization of visceral organs (n = 7). Both 4-Fr (n = 35) and 5-Fr (n = 46) sheaths were used. Technical success of DRA access was 97.6%, with conversion to transfemoral access in 2 cases (2.4%). No major complications were reported as a result of DRA access.ConclusionDRA access is a feasible and safe technique for abdominal interventional radiology embolization procedures. No radial artery occlusion or other major complications were observed in patients who underwent follow-up ultrasound.     

Percutaneous Access of the Modified Hutson Loop for Retrograde Cholangiography,Endoscopy, and Biliary Interventions

PurposeThe purpose of this study was to present the institutional experience of performing endoscopy, cholangiography, and biliary interventions through the modified Hutson loop by interventional radiology.Materials and MethodsA total of 61 of 64 modified Hutson loop access procedures were successful. This single-center retrospective study included 61 successful procedures of biliary interventions using existing modified Hutson loops (surgically affixed subcutaneous jejunal limb adjacent to biliary anastomosis or anastomoses) for diagnostic or therapeutic purposes in 21 patients. Seventeen of 21 patients (81%) had undergone liver transplantation. Indications included biliary strictures (n = 18) and biliary leaks (n = 3). The clinical success and complications were evaluated.ResultsThere were 3 of 26 modified Hutson loop retrograde biliary intervention failures (12%) before introduction of endoscopy and no failures (0 of 38 [0%]) subsequently (P = .06). Endoscopy or cholangioscopy was performed in 19 procedures by interventional radiologists. Retrograde biliary interventions included diagnostic cholangiography (n = 26), cholangioplasty (n = 25), stent placement (n = 29), stent retrieval (n = 25), and biliary drainage catheter placement (n = 5). No procedure-related mortality occurred. There was 1 major complication (duodenal perforation) (1.6%) and 12 minor complications (19%). In the 9 patients undergoing therapeutic interventions for biliary strictures, there was a significant decrease in median alkaline phosphatase (288.5 to 174.5 U/L; P = .03). There was a trend toward decrease in median bilirubin levels (1.7 to 1 mg/dL; P = .06) at 1 month post-intervention.ConclusionsThe modified Hutson loop provided interventional radiologists a safe and effective alternative access to manage biliary complications in patients with biliary-enteric anastomoses. Introduction of the endoscope in interventional radiology has improved the success rate of these procedures.     

Inline Balloon Occlusion–Assisted Delivery of Ethylene Vinyl Alcohol Copolymer for Peripheral Arterial Applications: A Multicenter Case Series

PurposeTo assess the feasibility, safety, and efficacy of balloon-assisted delivery of ethylene vinyl alcohol copolymer (EVOH) for a range of peripheral arterial applications.Materials and MethodsSix academic medical centers entered retrospective data on 46 consecutive patients (27 men, 19 women; ages, 11–94 y; mean age, 50.3 y) who underwent 60 balloon-assisted EVOH procedures. The cohort was restricted to procedures involving peripheral, nonneural arteries 1–5.5 mm in diameter. Clinical indications included a wide range of vascular pathologic conditions (most commonly arteriovenous malformations [n = 20], renal angiomyolipomas [n = 8], and acute hemorrhage [n = 9]) and targeted visceral and musculoskeletal peripheral arteries. Data collected included sex, age, clinical indication, arterial pathology, arteries embolized, type of occlusion balloon microcatheter, type and concentration of EVOH agent, effectiveness as an embolic backstop, vessels protected, adequacy of EVOH cast penetration, catheter extraction, nontarget embolization, and complications.ResultsBalloon occlusion prevented EVOH reflux in 59 of 60 procedures (98.3%). Nontarget EVOH embolization occurred in 2 procedures (3.3%). Adequate EVOH cast penetration and complete filling of the target pathologic structure were seen in 57 of 60 procedures (95%). Balloon deflation and uneventful extraction occurred in all procedures; small EVOH fragments detached into target arteries in 2 cases. One major (1.7%) and 2 minor (3.3%) complications occurred.ConclusionsBalloon-assisted EVOH embolization of peripheral arteries is feasible, safe, effective, and versatile. The primary advantage of balloon-assisted EVOH embolization is the ability to apply more injection pressure to advance the EVOH cast assertively into the pathologic structure(s).     

Iatrogenic Renal Artery Injury in 90 Cases: Arteriographic Findings and Outcomes after Embolization for Bleeding

PurposeTo evaluate differences in arteriographic findings and outcomes after embolization among patients with a suspected iatrogenic renal arterial injury (IRAI).Materials and MethodsPatients at the authors’ institution who underwent renal arteriography for suspected IRAIs after partial nephrectomy, biopsy, or percutaneous access over a 20-year period were included. Records, imaging, and outcomes were reviewed. Data analysis was performed using the Fisher exact or Kruskal-Wallis test.ResultsNinety arteriograms were performed on 83 patients after partial nephrectomy (n = 32), biopsy (n = 27), or percutaneous access (n = 24), including for nephrostomy/ureterostomy and stone removal. The median number of days between the index procedure and arteriogram was highest (15 days) after partial nephrectomy and lowest (5 days) after biopsy (P = .0001). Embolization was performed during 76% of arteriograms. If prearteriographic imaging showed positive results for IRAIs, embolization was performed in 67% versus 33% if imaging showed negative results (P = .005). The transfusion rate was higher after biopsy than after partial nephrectomy or percutaneous access (P = .002). Acute kidney injury after arteriogram occurred in 7% of patients; however, all returned to baseline by 1 week.ConclusionsDespite the different mechanism of IRAIs in partial nephrectomy, biopsy, and percutaneous access, arteriographic findings and outcomes were overall similar among groups. Prearteriographic imaging can help identify IRAIs but cannot supersede the clinical judgment regarding indication for embolization. IRAIs can present acutely or after a long interim, although patients who underwent biopsy presented earlier and more frequently required a blood transfusion. IRAIs can be treated with embolization without permanent deleterious effects on renal function.     

Bariatric Arterial Embolization with Calibrated Radiopaque Microspheres and an Antireflux Catheter Suppresses Weight Gain and Appetite-Stimulating Hormones in Swine

PurposeTo examine safety and efficacy of bariatric arterial embolization (BAE) with x-ray–visible embolic microspheres (XEMs) and an antireflux catheter in swine.Material and MethodsBAE with selective infusion of XEMs (n = 6) or saline (n = 4, control) into gastric fundal arteries was performed under x-ray guidance. Weight and plasma hormone levels were measured at baseline and weekly for 4 weeks after embolization. Cone-beam CT images were acquired immediately after embolization and weekly for 4 weeks. Hormone-expressing cells in the stomach were assessed by immunohistochemical staining.ResultsBAE pigs lost weight 1 week after embolization followed by significantly impaired weight gain relative to control animals (14.3% vs 20.9% at 4 weeks, P = .03). Plasma ghrelin levels were significantly lower in BAE pigs than in control animals (1,221.6 pg/mL vs 1,706.2 pg/mL at 4 weeks, P < .01). XEMs were visible on x-ray and cone-beam CT during embolization, and radiopacity persisted over 4 weeks (165.5 HU at week 1 vs 158.5 HU at week 4, P = .9). Superficial mucosal ulcerations were noted in 1 of 6 BAE animals. Ghrelin-expressing cell counts were significantly lower in the gastric fundus (17.7 vs 36.8, P < .00001) and antrum (24.2 vs 46.3, P < .0001) of BAE pigs compared with control animals. Gastrin-expressing cell counts were markedly reduced in BAE pigs relative to control animals (98.5 vs 127.0, P < .02). Trichrome staining demonstrated significantly more fibrosis in BAE animals compared with control animals (13.8% vs 8.7%, P < .0001).ConclusionsXEMs enabled direct visualization of embolic material during and after embolization. BAE with XEMs and antireflux microcatheters was safe and effective.     

Safety Profile of Particle Embolization for Treatment of Acute Lower Gastrointestinal Bleeding

PurposeTo assess ischemic adverse events following particle embolization when used as a second-line embolic to coil embolization for the treatment of acute lower gastrointestinal bleeding (LGIB).Materials and MethodsThe single-institution retrospective study examined 154 procedures where embolization was attempted for LGIB. In 122 patients (64 men; mean age, 69.9 years), embolization was successfully performed using microcoils in 73 procedures, particles in 34 procedures, and both microcoils and particles in 27 procedures. Particles were used as second-line only when coil embolization was infeasible or inadequate. Technical success was defined as angiographic cessation of active extravasation after embolization. Clinical success was defined as the absence of recurrent bleeding within 30 days of embolization.ResultsTechnical success for embolization of LGIB was achieved in 87% of the cases (134/154); clinical success rate was 76.1% (102/134) among the technically successful cases. Clinical success was 82.2% (60/73) for coils alone and 68.9% (42/61) for particles with or without coils. Severe adverse events involving embolization-induced bowel ischemia occurred in 3 of 56 (5.3%) patients who underwent particle embolization with or without coils versus zero of 66 patients when coils alone were used (P = .09). In patients who had colonoscopy or bowel resection within 2 weeks of embolization, ischemic findings attributable to the procedure were found in 3 of the 15 who underwent embolization with coils alone versus 8 of 18 who underwent embolization with particles with or without coils (P = .27).ConclusionsParticle embolization for the treatment of LGIB as second-line to coil embolization was associated with a 68.9% clinical success rate and a 5.3% rate of ischemia-related adverse events.     

Deep Learning Based on MR Imaging for Predicting Outcome of Uterine Fibroid Embolization

PurposeTo develop and validate a deep learning model based on routine magnetic resonance (MR) imaging obtained before uterine fibroid embolization to predict procedure outcome.Materials and MethodsClinical data were collected on patients treated with uterine fibroid embolization at the Hospital of the University of Pennsylvania from 2007 to 2018. Fibroids for each patient were manually segmented by an abdominal radiologist on a T1-weighted contrast-enhanced (T1C) sequence and a T2-weighted sequence of MR imaging obtained before and after embolization. A residual convolutional neural network (ResNet) model to predict clinical outcome was trained using MR imaging obtained before the procedure.ResultsInclusion criteria were met by 727 fibroids in 409 patients. At clinical follow-up, 85.6% (n = 350) of 409 patients (590 of 727 fibroids; 81.1%) experienced symptom resolution or improvement, and 14.4% (n = 59) of 409 patients (137 of 727 fibroids; 18.9%) had no improvement or worsening symptoms. The T1C trained model achieved a test accuracy of 0.847 (95% confidence interval [CI], 0.745–0.914), sensitivity of 0.932 (95% CI, 0.833–0.978), and specificity of 0.462 (95% CI, 0.232–0.709). In comparison, the average of 4 radiologists achieved a test accuracy of 0.722 (95% CI, 0.609–0.813), sensitivity of 0.852 (95% CI, 0.737–0.923), and specificity of 0.135 (95% CI, 0.021–0.415).ConclusionsThis study demonstrates that deep learning based on a ResNet model achieves good accuracy in predicting outcome of uterine fibroid embolization. If further validated, the model may help clinicians better identify patients who can most benefit from this therapy and aid clinical decision making.     

Predictive Value of Preprocedural Computed Tomography Angiography for the Technical Success of Transarterial Embolization of Type II Endoleaks Arising from the Lumbar Arteries

PurposeTo evaluate the ability of preprocedural computed tomography angiography (CTA) to predict the technical success of embolization of type II endoleak arising from a lumbar artery after endovascular aortic repair (EVAR).Materials and MethodsAll patients at a single academic institution who underwent angiography with possible embolization for a post-EVAR lumbar-supplied type II endoleak from 2009 to 2018 were retrospectively reviewed. Patients who did not undergo CTA before the procedure were excluded. CTAs were reviewed for the ability to trace the entire course of a feeding vessel from the internal iliac artery (IIA) to the lumbar artery at the site of the endoleak. Procedural imaging was reviewed for technical success, defined as the catheterization and embolization of the aneurysm sac through a lumbar artery.ResultsFifty-seven angiograms with a type II endoleak and suspected feeding lumbar artery were identified. On CTA acquired before the procedure, the arterial path supplying this lumbar artery could be traced from the IIA to the aneurysm sac in 18 (32%) patients. Embolization was technically successful in 16 of these 18 (89%) procedures compared with 10 of 39 (26%) procedures in which the supplying artery could not be traced using CTA (P < .001).ConclusionsA potential catheter path from the IIA through the iliolumbar and lumbar arteries to the aneurysm sac can be traced on preprocedural CTA in the minority of lumbar-supplied type II endoleaks. The ability to trace these inflow vessels may predict technical success during embolization. The low rate of technical success when the feeding vessel could not be traced using CTA suggests that these patients should be considered for percutaneous or transcaval sac puncture.     

Evaluation of Technical Success,Efficacy, and Safety of Portomesenteric Venous Intervention following Nontransplant Hepatobiliary or Pancreatic Surgery

PurposeTo evaluate technical success, efficacy and safety of portomesenteric venous (PMV) intervention for PMV stenosis or occlusion following nontransplant hepatobiliary or pancreatic (HPB) surgery.Materials and MethodsA retrospective review identified 42 patients (mean age 60 y) with PMV stenosis (n = 33; 79%) or occlusion (n = 9; 21%) who underwent attempted PMV intervention following HPB surgery between June 1, 2011, and April 1, 2018. Main outcomes were technical success, primary patency rates, and complications. Technical success was compared by venous pathology and primary PMV patency based on anticoagulation status after the procedure using Fisher exact test. Rates of primary patency by stent group were estimated using Kaplan-Meier method.ResultsTechnical success was 91% (n = 38/42) and significantly higher in patients with stenosis (n = 33/33; 100%) vs occlusion (n = 5/9; 56%) (P = .001). Primary presenting symptom resolved in 28 (87%) patients, including 6 (100%) patients with gastrointestinal bleeding. At mean imaging follow-up of 8.6 months ± 8.8, primary stent patency was 76%. There was no significant difference in primary stent patency based on anticoagulation status after the procedure (P = .48). There were 2 (4.8%) periprocedural complications.ConclusionsPortomesenteric venoplasty and stent placement following nontransplant HPB surgery is safe with a high rate of technical success if performed before chronic occlusion.     

A Rat Model of Frozen Shoulder Demonstrating the Effect of Transcatheter Arterial Embolization on Angiography,Histopathology, and Physical Activity

PurposeTo assess the angiographic findings and the effects of transcatheter arterial embolization on physical activity and histopathology using a frozen shoulder rat model.Materials and MethodsFirst, the angiographic and histopathologic findings of rats in which the shoulder was immobilized with molding plaster for 6 weeks (n = 4) were compared to control rats with normal non-immobilized shoulders (n = 4). Next, a total of 16 frozen shoulder rats were divided into 2 groups. In the transcatheter arterial embolization group (n = 8), imipenem/cilastatin was injected into the left thoracoacromial artery. The changes of physical activity before and after procedures were evaluated and compared with a saline-injected control group (n = 8). Histopathologic findings were also compared between the 2 groups.ResultsAngiography revealed abnormal shoulder staining in all of the rats with a frozen shoulder. On histopathology, the numbers of microvessels and mononuclear inflammatory cells in the synovial membrane of the joint capsule were significantly higher compared with the control rats (both P = .03). In the transcatheter arterial embolization group, the running distance and speed were improved (P = .03 and P = .01, respectively), whereas there were no significant differences in the control group. The number of microvessels and mononuclear inflammatory cells in the transcatheter arterial embolization group were significantly lower than the control group (P = .002 and P = .001, respectively).ConclusionsThe rat frozen shoulder model revealed the development of neovascularization. Transcatheter arterial embolization decreased the number of blood vessels and inflammatory changes in the frozen shoulder and increased the moving distance and speed of the rats.     

Embolic Characteristics of Imipenem-Cilastatin Particles in Vitro and in Vivo: Implications for Transarterial Embolization in Joint Arthropathies

PurposeTo elucidate in vitro and in vivo characteristics and embolic properties of imipenem-cilastatin (IPM-CS) compared with hydrogel microspheres.Materials and MethodsParticle size distribution was microscopically evaluated with 3 samples of 50 mg IPM-CS suspensions in each of 6 conditions by a mixture of contrast volume: 500 or 1000 μL and vortex mixing time: 5, 10, or 30 s. Time-dependent changes up to 3 h post-mixing were also evaluated. Fifteen male Sprague-Dawley rats (460.2 ± 5.0 g) underwent unilateral renal artery embolization using IPM-CS (n = 11) or hydrogel microspheres (n = 4). Follow-up angiography 48 h after embolization and histological evaluation, including acute tubular necrosis (ATN) and inflammation, were scored using a 5-point scale (from 0 = normal to 4 = severe).ResultsOver 91% of IPM-CS particles were <40 μm under all in vitro conditions. With the increased contrast volume, the average particle size also increased (mean ± standard deviation: 11.6 ± 13.9 vs 16.7 ± 18.2 μm for 500 and 1000 μL iodinated contrast, P < .001); however, the impact of the mixing/elapsed time were limited. At 48 h after embolization, all cases in the IPM-CS groups (11/11) showed major to complete recanalization versus no recanalization with hydrogel microspheres (0/4) (P < .001). The following are the median ATN and inflammation grades in the cortex (ventral/dorsal) and medulla (ventral/dorsal) in both groups: IPM-CS, ATN in cortex (2/4) and medulla (1/1), inflammation in cortex (0/0) and medulla (0/0); hydrogel microspheres, ATN in cortex (4/4) and medulla (3/2), inflammation in cortex (1/1) and medulla (1/1).ConclusionsIPM-CS suspension generated particles that were predominantly smaller than 40 μm and with unique short-term embolic effects, leaving predominantly peripheral ischemic changes.