Live MR Angiographic Roadmapping for Uterine Artery Embolization: A Feasibility Study

PurposeTo assess the feasibility of live magnetic resonance (MR) angiography roadmapping guidance for uterine artery (UA) embolization (UAE) for fibroid tumors.Materials and MethodsTwenty patients underwent UAE with live MR angiographic roadmapping. The pre-acquired MR angiography scan was coregistered with the live intraprocedural fluoroscopy stream to create a visual roadmap to direct the microcatheter during UAE. Patient radiation dose, as measured by dose–area product (DAP), procedure time, contrast medium volume, and fluoroscopy time, was recorded. For the first 10 patients, an additional parameter of contrast medium volume needed to catheterize each UA was recorded.ResultsIn all 20 patients (40 UAs), the MR angiography overlay on live fluoroscopy was accurate and allowed for successful catheterization of the UA, resulting in a technical success rate of 100%. In the subset of the initial 20 UAs (ie, the first 10 patients) in which this data point was recorded, 17 (85%) were successfully catheterized with no iodinated contrast medium at all, by purely relying on the MR angiography roadmap. Mean procedure time was 45 minutes (range, 30–99 min), mean contrast agent dose was 75 mL (range, 46–199 mL), and mean DAP was 155 Gy·cm² (range, 37–501 Gy·cm²).ConclusionsLive MR angiographic roadmapping is feasible and accurate for catheter guidance during UAE.     

Prospective,Randomized Study of Coil Embolization versus Surefire Infusion System during Yttrium-90 Radioembolization with Resin Microspheres

PurposeTo compare standard coil embolization versus the use of an antireflux microcatheter (ARM) in patients undergoing planning angiography before selective internal radiation therapy (SIRT).Materials and MethodsA prospective, single-center trial was performed in which 30 patients were randomly assigned to undergo SIRT with coil embolization or the use of an ARM. The coil group underwent detachable coil embolization of nontarget vessels, and the ARM group underwent infusion of macroaggregated albumin with use of an ARM system, without coil embolization. Single-photon emission computed tomography (CT)/CT was then performed to assess for nontarget distribution. The primary endpoint was fluoroscopy time during planning angiography. Secondary endpoints included deployment time, total procedure time, radiation dose–area product, contrast agent used, and adverse events. Endpoints were evaluated during planning angiography and SIRT.ResultsOver a 9-month period, 30 consecutive patients were randomized at a 1:1 ratio between coil embolization and ARM groups. Technical success rates were 100% in both groups. Mean fluoroscopy time was significantly reduced in the ARM group versus the coil embolization group (1.8 min [range, 0.4–4.9 min] vs 6.0 min [range, 1.9–15.7 min]; P = .002). The planning procedure time (P < .001), deployment time (P < .001), dose–area product (P = .04), and amount of contrast agent used (P < .001) were also significantly less in the ARM group than in the coil embolization group. No nontarget distribution was detected in either group. There was no difference between groups in dose delivered on the day of SIRT (P = .71). There were no major or minor adverse events at 30 days.ConclusionsThe use of an ARM during planning angiography can significantly reduce fluoroscopy time, procedure time, and radiation dose.     

Inferior Mesenteric Artery Collaterals to the Uterus during Uterine Artery Embolization: Prevalence,Risk Factors,and Clinical Outcomes

PurposeTo evaluate the prevalence of inferior mesenteric artery (IMA) collaterals to the uterus found during uterine artery embolization (UAE), associated risk factors, and clinical outcomes.Materials and MethodsThe records of 559 women who underwent UAE during the period 2008–2011 for uterine fibroids or adenomyosis found on magnetic resonance imaging were retrospectively analyzed. If IMA collaterals to the uterus were suspected on aortography performed after embolization, selective angiography was performed. Risk factors for IMA collaterals to the uterus were analyzed, including the presence of adenomyosis, baseline uterine volume, or prior pelvic surgery.ResultsCollaterals to the uterus were found from the ovarian artery (n = 21; 3.8%), IMA (n = 7; 1.3%), round ligament artery (n = 1; 0.2%), and internal pudendal artery (n = 1; 0.2%). IMA collaterals were found in seven patients. Of 185 patients, 6 (3.2%) had adenomyosis, with or without fibroids, which was significantly more frequent than the 1 (0.27%) of 374 patients who had fibroids only (P = .006). On multiple logistic regression analysis, the presence of adenomyosis (odds ratio, 19.556; P = .0168) and uterine volume (odds ratio, 1.003; P = .0069) were independent factors for the presence of IMA collaterals. Of the seven patients with IMA collaterals, embolization was not attempted in six, resulting in clinical failure in four. One patient who underwent IMA embolization with coils experienced clinical improvement.ConclusionsThe IMA was the second most common (1.3%) source of collaterals to the uterus. IMA collaterals were more frequent in patients with adenomyosis than in patients with fibroids only, resulting in high frequency of treatment failure.     

Transcatheter CT Arterial Portography and CT Hepatic Arteriography for Liver Tumor Visualization during Percutaneous Ablation

PurposeTo evaluate the feasibility of combining transcatheter computed tomography (CT) arterial portography or transcatheter CT hepatic arteriography with percutaneous liver ablation for optimized and repeated tumor exposure.Materials and MethodsStudy participants were 20 patients (13 men and 7 women; mean age, 59.4 y; range, 40–76 y) with unresectable liver-only malignancies—14 with colorectal liver metastases (29 lesions), 5 with hepatocellular carcinoma (7 lesions), and 1 with intrahepatic cholangiocarcinoma (2 lesions)—that were obscure on nonenhanced CT. A catheter was placed within the superior mesenteric artery (CT arterial portography) or in the hepatic artery (CT hepatic arteriography). CT arterial portography or CT hepatic arteriography was repeatedly performed after injecting 30–60 mL 1:2 diluted contrast material to plan, guide, and evaluate ablation. The operator confidence levels and the liver-to-lesion attenuation differences were assessed as well as needle-to-target mismatch distance, technical success, and technique effectiveness after 3 months.ResultsTechnical success rate was 100%; there were no major complications. Compared with conventional unenhanced CT, operator confidence increased significantly for CT arterial portography or CT hepatic arteriography cases (P < .001). The liver-to-lesion attenuation differences between unenhanced CT, contrast-enhanced CT, and CT arterial portography or CT hepatic arteriography were statistically significant (mean attenuation difference, 5 HU vs 28 HU vs 70 HU; P < .001). Mean needle-to-target mismatch distance was 2.4 mm ± 1.2 (range, 0–12.0 mm). Primary technique effectiveness at 3 months was 87% (33 of 38 lesions).ConclusionsIn patients with technically unresectable liver-only malignancies, single-session CT arterial portography–guided or CT hepatic arteriography–guided percutaneous tumor ablation enables repeated contrast-enhanced imaging and real-time contrast-enhanced CT fluoroscopy and improves lesion conspicuity.     

Embolization of Angiographically Visible Type I and II Utero-ovarian Anastomoses during Uterine Artery Embolization for Fibroid Tumors: Impact on Symptom Recurrence and Permanent Amenorrhea

PurposeTo compare the incidences of symptom recurrence and permanent amenorrhea following uterine artery embolization (UAE) for symptomatic fibroid tumors in patients with type I and II utero-ovarian anastomoses (UOAs) with versus without ovarian artery embolization (OAE).Materials and MethodsA retrospective, institutional review board–approved study of 99 women who underwent UAE for symptomatic fibroid tumors from April 2005 to October 2010 was conducted to identify patients who had type I or II UOAs at the time of UAE. Based on the embolization technique, patients were categorized into standard (ie, UAE only), combined (ie, UAE and OAE), and control (patients without UOAs who underwent UAE) groups. Data collected included patient characteristics, procedural technique and findings, symptom recurrence, secondary interventions, and permanent amenorrhea. Statistical analysis was performed with the Fisher exact test, with significance reached at P < .05.ResultsTwenty patients (20.2%; mean age, 46.9 y ± 6.3) had type I (n = 3) or II (n = 17) UOAs. Thirteen (65%) underwent UAE only (standard group) and seven (35%) underwent UAE and OAE (combined group). There were no significant differences between groups in demographics or in the incidence of permanent amenorrhea after procedures (follow-up, 561 d ± 490). There was a significantly higher incidence of symptom recurrence in the standard group compared with the control group (P = .01), with no differences between combined and control groups (P = 1).ConclusionsThere were no statistical differences in permanent amenorrhea rates in the groups studied, with significantly higher symptom recurrence rates observed when OAE was not performed in the setting of UOA.     

Targeting and Recanalization after Embolization with Calibrated Resorbable Microspheres versus Hand-cut Gelatin Sponge Particles in a Porcine Kidney Model

PurposeTo report on polyethylene glycol hydrogel-based resorbable embolization microspheres (REM) that were synthesized to resorb in < 24 hours, before inflammation and vascular remodeling, to achieve a complete arterial recanalization and to compare targeting and recanalization of REM of 300–500 µm, 500–700 µm, and 700–900 µm with hand-cut gelatin sponge particles (GSP).Materials and MethodsEight pigs underwent polar renal artery embolization with REM or GSP. Angiograms were obtained before embolization and 10 minutes and 7 days after embolization before pigs were sacrificed to determine the occlusion level, the percentage of occlusion, and the recanalization rate for each product. The distribution of embolic material was assessed in pathology, and infarction rate of the kidneys was measured.ResultsREM of 300–500 µm occluded more distal vessels than REM of 500–700 µm and 700–900 µm. At day 7, the recanalization rate was complete for the larger REM, whereas it was about 60% for the two smaller sizes. REM were completely degraded, with no residual material or inflammation. GSP occluded more proximal arteries than REM of 700–900 µm, were partly degraded at day 7, and were accompanied by a foreign body reaction in proximal and distal arteries. GSP recanalized at 79%. The infarction rate was higher with the two smaller sizes of REM and with GSP than with the largest REM.ConclusionsREM of different sizes targeted different occlusion levels in kidney arteries. GSP provided an extended occlusion level without actual targeting. Regardless of embolic material used, angiographic recanalization of renal arteries depended on the extent of necrosis. REM of 700–900 µm demonstrated the lowest infarction rate and the best recanalization rate.     

Apparent Diffusion Coefficient of Uterine Leiomyoma as a Predictor of the Potential Response to Uterine Artery Embolization

PurposeTo determine the utility of the apparent diffusion coefficient (ADC) of uterine leiomyoma for prediction of the potential response to uterine artery embolization (UAE).Materials and MethodsThis prospective study included 49 patients with uterine leiomyomas who underwent diffusion-weighted magnetic resonance (MR) imaging before UAE between May 2011 and January 2012. All patients also underwent 3-month follow-up MR imaging after UAE. Using conventional and diffusion-weighted MR imaging sequences, 72 uterine leiomyomas ≥ 3 cm were prospectively evaluated. The volume of each leiomyoma was calculated, and quantitative measurement of ADC was performed. Regression analysis was used to evaluate the relationship between ADC and volumetric response after UAE. Receiver operating characteristic curve analysis was performed to determine the sensitivity and specificity of ADC for prediction of the potential response to UAE. Interclass correlation coefficient analysis was used to assess interobserver variability between two radiologists.ResultsVolume reduction rates of leiomyomas after UAE ranged from 0.2%–89.1% (mean, 44.1%). ADC ranged from 0.559 × 10^?3 mm²/s to 1.814 × 10^?3 mm²/s (mean, 1.170 × 10^?3 mm²/s). ADC was statistically significantly related to volumetric response of leiomyomas (P = .014). Using a threshold of 1.092 × 10^?3 mm²/s, the sensitivity and specificity of ADC for prediction of > 50% volume reduction of the leiomyoma after UAE were 82.6% and 52.3%, respectively. Using a threshold of 1.023 × 10^?3 mm²/s, the sensitivity and specificity of ADC for prediction of < 30% volume reduction were 80.8% and 33.3%, respectively. The interclass correlation coefficient for measuring ADC of uterine leiomyomas between two radiologists was 0.98.ConclusionsADC of uterine leiomyomas was significantly related to the volume reduction after UAE. ADC may be useful in predicting the potential response to UAE. A high ADC of the uterine leiomyoma may be associated with a greater volume reduction after UAE.     

Clinical Features and Endovascular Management of Iliac Artery Fibromuscular Dysplasia

PurposeTo identify the spectrum of clinical presentation of iliac artery fibromuscular dysplasia (FMD) and to evaluate the outcomes of endovascular management of iliac artery FMD for claudication.Materials and MethodsAll patients in a single institution with a diagnosis of FMD between January 1980 and December 2010 were identified. Iliac artery FMD was present in 14 patients. Associated risk factors included hypertension (79%), hyperlipidemia (64%), smoking history (36%), coronary artery disease (21%), diabetes (0%), and obesity (36%).ResultsIn eight (57%) patients, iliac artery FMD was incidentally found on imaging. Lifestyle-limiting claudication involving one or both extremities was present in six (43%) patients. All six patients were reported to have mild peripheral arterial disease based on ankle-brachial index measurements (0.7–0.9). These six patients underwent 10 endovascular procedures for claudication, including angioplasty (n = 8) and self-expanding stent placement (n = 2). Mean symptom-free survival was 56.3 months.ConclusionsIliac artery FMD that is amenable to endovascular treatment may be found incidentally or may manifest with disabling claudication.     

Percutaneous Intraportal Application of Adipose Tissue–derived Mesenchymal Stem Cells Using a Balloon Occlusion Catheter in a Porcine Model of Liver Fibrosis

PurposeTo investigate the safety and effectiveness of a novel endovascular approach for therapeutic cell delivery using a balloon occlusion catheter in a large animal model of liver fibrosis.Materials and MethodsTranscatheter arterial embolization with ethiodized oil (Ethiodol) and ethanol was used to induce liver damage in 11 pigs. Mesenchymal stem cells (MSCs) were harvested from adipose tissue and engineered to express green fluorescent protein (GFP). A balloon occlusion catheter was positioned in the bilateral first-order portal vein branches 2 weeks after embolization to allow intraportal application of MSCs in six experimental animals. MSCs were allowed to dwell for 10 minutes using prolonged balloon inflation. Five control animals received a sham injection of normal saline in a similar fashion. Hepatic venous pressure gradient (HVPG) was measured immediately before necropsy. Specimens from all accessible lobes were obtained with ultrasound-guided percutaneous 18-gauge biopsy 2 hours after cell application. All animals were euthanized within 4 weeks. Fluorescent microscopy was used to assess the presence and distribution of cells.ResultsLiver injury and fibrosis were successfully induced in all animals. MSCs (6–10 × 10⁷) were successfully delivered into the portal vein in the six experimental animals. Cell application was not associated with vascular complications. HVPG showed no instances of portal hypertension. GFP-expressing MSCs were visualized in biopsy specimens and were distributed primarily within the sinusoidal spaces; however, 4 weeks after implantation, MSCs could not be identified in histologic specimens.ConclusionsA percutaneous endovascular approach for cell delivery using a balloon occlusion catheter proved safe for intraportal MSC application in a large animal model of liver fibrosis.     

A Novel Resorbable Embolization Microsphere for Transient Uterine Artery Occlusion: A Comparative Study with Trisacryl-Gelatin Microspheres in the Sheep Model

PurposeTo evaluate angiographic recanalization, inflammatory reaction, and uterine damage after sheep uterine artery embolization (UAE) with a novel calibrated resorbable embolization microsphere (REM) and compare the results with control nonresorbable microspheres.Materials and MethodsSix hormonally artificially cycled sheep underwent bilateral UAE until stasis with either REM or trisacryl-gelatin microspheres (TGMS). At 7 days, control angiograms were obtained to assess the residual vascularization at arterial and parenchymal phases. The animals were then sacrificed for analysis of the presence of microspheres, inflammatory foreign body reaction, and surface areas of uterine damage.ResultsMean volume of microspheres injected per uterine artery (UA) or per animal did not differ between groups. At day 7, the flow was normal for six of six UAs that received embolization with REM versus only three of six UAs with TGMS (P = .0455, χ² test). Uterine parenchymography showed no defects in six UAs in the REM group versus five defects in six UAs in the TGMS group (P = .0060, χ² test). No REM or residual fragments of microspheres were observed on histologic analysis. TGMS were observed in tissues and accompanied by a mild inflammatory response. Necrosis rates were not significantly different between the two products, either in endometrium (REM 23.5% ± 28.8% [median 8.1%] vs TGMS 21.8% ± 23.7% [median 14.6%]) or in myometrium (REM 8.2% ± 22.7% [median 0.0%] vs TGMS 8.8% ± 20.8% [median 0.9%]). Endometrium alteration rate was lower with REM than with TGMS (39.7% ± 25.7% [median 34%] vs 60.6% ± 27.1% [median 71%]; P = .0060, Mann-Whitney test). Myometrium alteration rates were not significantly different between REM (45.7% ± 37.1% [median 63.0%]) and TGMS (37.8% ± 34.0% [median 19.1%]).ConclusionsAt 1 week after sheep UAE with REM, the recanalization was complete, the microspheres were completely degraded, and there was no remnant inflammatory response.     

Retrospective Review of Angiography before Cannulation of Newly Created Vascular Accesses in Hemodialysis Patients

PurposeTo investigate vascular access status before first cannulation and the clinical implications of angiography performed before cannulation.Materials and MethodsA retrospective review of 300 consecutive patients who underwent angiography after vascular access surgery and before cannulation between August 2004 and April 2010 was performed. Angiography was performed 4–6 weeks after the surgery but before the first cannulation.ResultsAngiography revealed 94 (31.3%) cases of severe stenosis (≥ 50% luminal narrowing) that required percutaneous transluminal angioplasty (PTA) or a second operation. No stenosis was observed in 122 (40.7%) cases, and mild stenosis (< 50% luminal narrowing) was observed in 84 (28%) cases. For the 94 cases with severe stenosis, PTA was performed in 66, and a second operation was performed in 16. In the other cases (n = 12), HD was maintained by a permanent catheter, or the patients were transferred to another institution. PTA was an immediate success in all patients who underwent the procedure except two. Of 84 patients with mild stenosis, 70 were followed for 1 year; vascular access dysfunction occurred in 15, and 11 of these underwent successful PTA. Of the 122 patients with normal angiographic findings, 102 were followed for 1 year, and vascular access dysfunction did not occur in any of these patients.ConclusionsEarly postoperative angiography before the first hemodialysis is helpful for the early detection and treatment of vascular access dysfunction.     

Incidence of Additional Treatments in Women Treated with MR-Guided Focused US for Symptomatic Uterine Fibroids: Review of 138 Patients with an Average Follow-up of 2.8 Years

PurposeTo assess long-term outcomes of magnetic resonance (MR)–guided focused ultrasound (US) treatments of uterine fibroids.Materials and MethodsA retrospective follow-up of 138 patients treated at a single institution between March 2005 and November 2011 was conducted. The patients were not part of a clinical study and were followed through retrospective review of their medical records and telephone interviews to assess additional treatments for fibroid-related symptoms. Survival methods, including Cox proportional hazards models, were used to assess the association between incidence of additional treatments and patient data obtained during screening before treatment.ResultsThe average length of follow-up was 2.8 years (range, 1–7.2 y). The cumulative incidence of additional treatments at 36 months and 48 months after MR-guided focused US was 19% and 23%, respectively. Women who did not need additional treatment were older than women who did (46.3 y ± 5.6 vs 43.0 y ± 5.8; P = .006; hazard ratio, 0.855; 95% confidence interval, 0.789–0.925). Additionally, women with heterogeneous or bright fibroids on T2-weighted MR imaging were more likely to require additional treatment compared with women with homogeneously dark fibroids (hazard ratio, 5.185 or 5.937, respectively; 95% confidence interval, 1.845–14.569 or 1.401–25.166, respectively). Physician predictions of treatment success, recorded during the screening process, had significant predictive value (P = .018).ConclusionsThe long-term rates of additional interventions after MR-guided focused US of symptomatic uterine fibroids were found to be comparable with other uterine-sparing procedures, such as uterine artery embolization or myomectomy. Older patient age and homogeneously dark fibroids were associated with fewer additional treatments. Physician assessment of treatment success was found to be a valuable tool in patient screening.     

Effect of Real-Time Radiation Dose Feedback on Pediatric Interventional Radiology Staff Radiation Exposure

PurposeTo measure and compare individual staff radiation dose levels during interventional radiologic (IR) procedures with and without real-time feedback to evaluate whether it has any impact on staff radiation dose.Materials and MethodsA prospective trial was performed in which individuals filling five different staff roles wore radiation dosimeters during all IR procedures during two phases: a 12-week “closed” phase (measurements recorded but display was off, so no feedback was provided) and a 17-week “open” phase (display was on and provided real-time feedback). Radiation dose rates were recorded and compared by Mann–Whitney U test.ResultsThere was no significant difference in median procedure time, fluoroscopy time, or patient dose (dose–area product normalized to fluoroscopy time) between the two phases. Overall, the median staff dose was lower in the open phase (0.56 µSv/min of fluoroscopy time) than in the closed phase (3.01 µSv/min; P < .05). The IR attending physician dose decreased significantly for procedures for which the physicians were close to the patient, but not for ones for which they were far away.ConclusionsA radiation dose monitoring system that provides real-time feedback to the interventional staff can significantly reduce radiation exposure to the primary operator, most likely by increasing staff compliance with use of radiation protection equipment and dose reduction techniques.     

Selective Arterial Embolization with Ethylene–Vinyl Alcohol Copolymer for Control of Massive Lower Gastrointestinal Bleeding: Feasibility and Initial Experience

PurposeTo evaluate the efficacy, safety, and clinical outcomes of superselective embolization using ethylene–vinyl alcohol copolymer (Onyx Liquid Embolic System; ev3 Neurovascular, Irvine, California) as the primary treatment for acute and massive lower gastrointestinal bleeding (LGIB).Materials and MethodsBetween January 2008 and October 2013, all patients with focal massive LGIB who were treated by embolization were retrospectively analyzed. The study was approved by the hospital’s ethics committee; informed consent was obtained in all cases. Onyx was chosen as the embolic agent in all cases in an intention-to-treat fashion. Embolization was indicated in 31 consecutive patients (mean age, 80 y ± 11.1). Multidetector computed tomography and digital subtraction angiography were performed in all patients.ResultsActive bleeding was detected in all cases. A colonoscopy was performed in 11 patients. The correlation between multidetector computed tomography and angiography findings was 96.7%. The causes of bleeding were diverticula in 15 patients, iatrogenic in 7 patients, neoplasia in 3 patients, hemorrhoids in 2 patients, angiodysplasia in 2 patients, and unknown in 2 patients. Embolization was not possible in one patient, who required urgent left hemicolectomy. The technical success rate was 93.5%. The embolic material refluxed in one patient, causing an undesired embolization, without any clinical consequences. In the 30 patients who received embolization, the immediate bleeding control rate was 100%. Rebleeding at 30 days occurred in three patients (10%). There were no major complications, intestinal ischemia, or deaths attributable to the treatment. No patient needed surgery or new embolization during a mean follow-up period of 23.7 months (range, 1–71 mo).ConclusionsControl of massive LGIB using superselective embolization with Onyx is feasible and safe.     

Pharmacokinetics and Antitumor Efficacy of Chemoembolization Using 40 µm Irinotecan-Loaded Microspheres in a Rabbit Liver Tumor Model

PurposeTo evaluate the pharmacokinetics and antitumor efficacy of 40 μm irinotecan-loaded drug-eluting microspheres (Embozene TANDEM Microspheres; CeloNova BioSciences, Inc, San Antonio, Texas) (TANDEM-IRI).Materials and MethodsThe following three groups included eight VX2 rabbits each: group 1, full-loaded (50 mg irinotecan/1 mL TANDEM)/high-dose injection (1 mg irinotecan/kg); group 2, full-loaded (50 mg irinotecan/1 mL TANDEM)/low-dose injection (0.5 mg irinotecan/kg); and group 3, half-loaded (25 mg irinotecan/1 mL TANDEM)/low-dose injection (0.5 mg irinotecan/kg). Irinotecan and SN-38 in the plasma and tumors were measured within 72 hours. Histologic examinations were conducted on days 1, 3, and 7.ResultsSerum irinotecan levels remained near the maximum concentration for 180 minutes after transarterial chemoembolization; in group 1, levels were 351.4 ng/mL at 30 minutes, 329.0 ng/mL at 60 minutes, and 333.5 ng/mL at 180 minutes. The area under the curve for 0–24 hours of irinotecan in group 1 was approximately two times higher than the same value in groups 2 and 3. High irinotecan and SN-38 concentrations in the tumors were measured at 24 hours and 72 hours. After transarterial chemoembolization, levels of liver enzymes aspartate aminotransferase and alkaline phosphatase were significantly higher in group 1 compared with groups 2 and 3. Histologic findings showed microspheres had deeply penetrated into tumors. Significantly higher tumor necrosis ratios were observed in groups 1 (86.6%–90.0%) and 3 (90.0%–100%) compared with group 2 (63.3%–70%) (P = .031 and P = .016).ConclusionsSlow drug release with high drug concentration in tumors can be provided with 40 μm TANDEM-IRI. When complete arterial embolization is performed, the dose of irinotecan loaded on 40 μm TANDEM microspheres can be reduced while maintaining efficacy.     

Forcible Intraarterial Injection of a Nonadhesive Liquid Embolic Agent under Microballoon Occlusion: Experimental Study in Swine Liver

PurposeTo evaluate the feasibility and effectiveness of transcatheter embolization by forcible intraarterial injection of a mixture of ethylene vinyl alcohol copolymer (EVAL) and ethanol under microballoon occlusion compared with conventional transcatheter arterial embolization methods in nontumoral swine liver.Materials and MethodsNine swine were divided into three groups: embolization with EVAL/ethanol mixture (EVAL group, n = 5), with ethiodized oil (ethiodized oil group, n = 2), and with microspheres (microspheres group, n = 2). Embolization was performed at the subsegmental hepatic artery. The EVAL/ethanol mixture was injected forcibly through a microcatheter with a balloon, which was inflated to prevent backflow of the mixture during the injection. Ethiodized oil or microspheres were injected into the artery using a microcatheter without balloon occlusion. Two animals of the EVAL group were euthanized immediately after embolization, and the distribution of EVAL was assessed microscopically. The remaining seven animals were euthanized 4 weeks after embolization, and the histopathologic changes were assessed.ResultsAll procedures were technically successful. EVAL occupied > 80% of the hepatic arterial, portal venous, and sinusoidal lumens after embolization. Ischemic coagulation necrosis was observed 4 weeks after embolization in the EVAL group. Parenchymal necrosis was not observed in the ethiodized oil and microspheres groups.ConclusionsTranscatheter embolization by forcible intraarterial injection of an EVAL/ethanol mixture under microballoon occlusion was feasible and achieved the simultaneous embolization of hepatic artery, portal vein, and sinusoids in swine liver, resulting in complete necrosis of the segment that received embolization.     

Comparison of Polyvinyl Alcohol Microspheres and Tris-Acryl Gelatin Microspheres for Uterine Fibroid Embolization: Results of a Single-Center Randomized Study

PurposeTo assess the efficacy of two embolic agents in the treatment of symptomatic uterine leiomyomas.Materials and MethodsA randomized, prospective, single-center study enrolled 60 women with symptomatic uterine leiomyomas. Uterine artery embolization (UAE) with spherical polyvinyl alcohol (SPVA) microspheres (n = 30; 700–900 μm and 900–1,200 μm; near-stasis or stasis endpoint) and tris-acryl gelatin (TAG) microspheres (n = 30; 500–700 μm; “pruned-tree” endpoint) was performed. Infarction rates were calculated for the dominant tumor and for small (< 2 cm) and large (> 2 cm) nondominant tumors. The primary endpoint was tumor infarction at 24 hours measured by contrast-enhanced magnetic resonance imaging assessed by a blinded reviewer.ResultsBaseline characteristics were similar between groups. The primary endpoint was similar in both treatments (≥ 91% dominant tumor infarction; SPVA. 86.2%; TAG, 93.3%, P = .35). Complete infarction (100%) was also similar between arms at 24 hours and 3 months. Symptom severity was reduced and quality of life improved equally at 3 and 12 months in each treatment group. Complications were minor in both groups.ConclusionsUterine leiomyoma infarction at 24 hours and 3 months after treatment with SPVA or TAG microspheres was comparable when using near-stasis as a procedural endpoint with SPVA microspheres. Symptom relief was maintained for as long as 12 months for both embolic agents.     

The Role of Accessory Obturator Arteries in Prostatic Arterial Embolization

In 9 of 491 patients (1.8%) who underwent prostatic arterial embolization (PAE) for benign prostatic hyperplasia from March 2009–November 2013, prostatic arteries arose from the external iliac artery via an accessory obturator artery (AOA). Computed tomography angiography performed before the procedure identified the variant and allowed planning before the procedure. The nine AOAs were catheterized from a contralateral femoral approach. Bilateral PAE was technically successful in the nine patients. There was a mean decrease in international prostate symptom score of 6.5 points and a mean prostate volume reduction of 15.1% (mean follow-up, 4.8 mo) in the nine patients.     

Coil Embolization of the Splenic Artery: Impact on Splenic Volume

PurposeTo determine the impact of coil embolization of the splenic artery on splenic volume based on computed tomography (CT) imaging.Materials and MethodsSplenic artery embolization (SAE) was performed in 148 consecutive patients over an 8-year period in an institutional review board–approved retrospective study. Of these, 60 patients (36 men; mean age, 49 y) had undergone contrast-enhanced CT before and after SAE with a mean time interval of 355 days. Pre- and postembolization splenic volumes were calculated with volume-rendering software. Presence of Howell–Jolly bodies was ascertained on laboratory tests. A trauma control group consisted of 39 patients with splenic laceration and follow-up CT but no splenic intervention.ResultsSAE in trauma patients resulted in an insignificant decrease in mean spleen size from 224 cm³ to 190 cm³ (P = .222). However, postembolization splenic volume was significantly smaller than follow-up volume in the trauma control group (353 cm³; P < .001). In nontrauma patients, the mean splenic volume decreased from 474 cm³ to 399 cm³ after SAE (P = .068). Multivariable analysis revealed that coil pack location was the only factor significantly affecting resultant splenic volume (P = .016). For trauma and nontrauma patients, distal embolization resulted in significant splenic volume loss (P = .034 and P = .013), whereas proximal embolization did not. No patients had persistent circulating Howell–Jolly bodies after SAE. No patients required repeat embolization or splenectomy.ConclusionsCoil embolization of the splenic artery resulted in a modest but significant decrease in splenic volume when performed distally; proximal embolization resulted in an insignificant volume change.