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Purpose: To investigate and compare venous sac and feeding artery embolization (VFE) with feeding artery embolization (FAE) alone for treatment of pulmonary arteriovenous malformations (PAVMs), based on difference in outcomes in decrease of the size of the draining vein., Materials and Methods: Twenty-six patients (7 male and 19 female; median age [interquartile range], 58 years [46-65 years]) with 42 simple PAVMs treated with coil embolization between August 2005 and December 2018 were retrospectively evaluated. Twenty PAVMs were treated with FAE early in the study period and compared with 22 PAVMs treated with VFE later in the study period. Follow-up computed tomography images obtained 8-20 months after embolotherapy were used for outcome analysis. Data related to patient demographics; follow-up period; baseline diameters of the feeding artery, venous sac, and draining vein; draining vein diameter after treatment; and decrease in the size of the draining vein, including the number reaching a threshold of 70% decrease, were compared between the 2 groups., Results: The draining vein decreased in size by a median of 46.4% in the FAE group and 66.3% in the VFE group, and the difference between the 2 groups was statistically significant (P = .009). There were no significant differences in the other parameters., Conclusions: VFE leads to a greater decrease in the size of the draining vein than FAE, suggesting that VFE results in more complete occlusion than FAE for treatment of PAVMs., (Copyright © 2021 SIR. Published by Elsevier Inc. All rights reserved.)

Objectives: This study aimed to assess the diagnostic accuracy of computed tomography (CT) and time-resolved magnetic resonance angiography (TR-MRA) for patency after coil embolization of pulmonary arteriovenous malformations (PAVMs) and identify factors affecting patency., Methods: Data from the records of 205 patients with 378 untreated PAVMs were retrospectively analyzed. Differences in proportional reduction of the sac or draining vein on CT between occluded and patent PAVMs were examined, and receiver operating characteristic analysis was performed to assess the accuracy of CT using digital subtraction angiography (DSA) as the definitive diagnostic modality. The accuracy of TR-MRA was also assessed in comparison to DSA. Potential factors affecting patency, including sex, age, number of PAVMs, location of PAVMs, type of PAVM, and location of embolization, were evaluated., Results: The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of CT were 82%, 81%, 77%, 85%, and 82%, respectively, when the reduction rate threshold was set to 55%, which led to the highest diagnostic accuracy. The sensitivity, specificity, PPV, NPV, and accuracy of TR-MRA were 89%, 95%, 89%, 95%, and 93%, respectively. On both univariable and multivariable analyses, embolization of the distal position to the last normal branch of the pulmonary artery was a factor that significantly affected the prevention of patency., Conclusions: TR-MRA appears to be an appropriate method for follow-up examinations due to its high accuracy for the diagnosis of patency after coil embolization of PAVMs. The location of embolization is a factor affecting patency., Key Points: • Diagnosis of patency after coil embolization for pulmonary arteriovenous malformations (PAVMs) is important because a patent PAVM can lead to neurologic complications. • The diagnostic accuracies of CT with a cutoff value of 55% and TR-MRA were 82% and 93%, respectively. • The positioning of the coils relative to the sac and the last normal branch of the artery was significant for preventing PAVM patency.

Purpose: To evaluate the safety and effectiveness of hydrogel-coated coils for vessel occlusion in the body trunk., Materials and Methods: A total of 77 patients with various peripheral vascular lesions, treatable by embolization with coils, were randomized (hydrogel group, n = 38; nonhydrogel group, n = 39). In the hydrogel group, embolization of the target vessel was conducted using 0.018-inch hydrogel-coated coils (AZUR 18; Terumo Medical Corporation, Tokyo, Japan) with or without bare platinum coils. The nonhydrogel group received both bare platinum coils and fibered coils without the use of hydrogel-coated coils., Results: Complete target vessel occlusion was accomplished in 36 patients in the hydrogel group and 37 patients in the nonhydrogel group. No major adverse events were observed in either group. The median number of coils/vessel diameter and the median total coil length/vessel diameter were significantly larger in the nonhydrogel group than in the hydrogel group (P = .005 and P = .004, respectively). The median embolization length was significantly longer in the nonhydrogel group (31.95 mm) than in the hydrogel group (23.43 mm) (P = .002). If no expansion was assumed, the median packing density in the hydrogel group was 44.9%, which was similar to that in the nonhydrogel group (46.5%) (P = .79). With full expansion assumed, the median packing density in the hydrogel group was 125.7%., Conclusions: Hydrogel-coated coils can be safely used for peripheral vascular coil embolization, and hydrogel-coated and conventional coils in combination allow for a shorter embolization segment and shorter coil length., (Copyright © 2020 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To retrospectively evaluate the role of selective renal artery embolization for renal arteriovenous fistulae (AVFs) with dilated venous sac., Materials and Methods: Between 2002 and 2015, 14 patients (7 men and 7 women; mean age, 60 years) with a single renal AVF with dilated venous sac underwent selective renal artery embolization. Three patients presented with gross hematuria, 4 presented with occult blood in urine, and 1 presented with chronic heart failure. Five patients had a history of renal biopsy or partial nephrectomy. Embolic agents used included pushable fibered coils, detachable microcoils, hydrogel coils, N-butyl 2-cyanoactylate, and/or absolute ethanol. Technical success was defined as complete angiographic occlusion of the renal AVF without visualization of the venous sac. Clinical success was defined as the disappearance of the AVF on ultrasound and contrast-enhanced computed tomography, without any symptoms., Results: Fifteen sessions of selective renal artery embolization were performed. Technical success was achieved in 13 sessions (86.7%). Clinical success was achieved in 13 patients (92.9%) after a mean follow-up of 48 months (range, 6-155 months). Two major complications occurred-renal vein thrombosis (n = 1) and renovascular hypertension (n = 1)-and were successfully managed with warfarin and an angiotensin-II receptor blocker, respectively. The former patient required re-embolization because of recanalization. No significant changes were observed in the mean serum creatinine level (.86 mg/dL vs .85 mg/dL; P = .67) and the mean estimated glomerular filtration rate (66.0 mL/min/1.73m 2 vs 67.4 mL/min/1.73m 2 ; P = .4) after 6 months., Conclusions: Selective renal artery embolization is a safe and effective treatment for renal AVFs with dilated venous sac., (Copyright © 2018 SIR. Published by Elsevier Inc. All rights reserved.)

Microscopic subinguinal varicocelectomy has a recurrence of less than 1%, and varicocele recurrence is supposed to be an uncommon post-surgery adverse event. At present, no guidelines exist for the management of recurrent varicoceles after surgery. In this report, we present two cases of post-surgery recurrent varicocele of the testis. Case_1 : A 23-year-old male patient who had undergone microscopic subinguinal varicocelectomy for a grade 3 varicocele was referred to our hospital because of recurrent varicocele. Retrograde venography revealed the persistence of dilated spermatic veins. The former surgeon preserved the dilated vas deferens vein, and this was considered a possible cause of persistence of dilated spermatic veins. The vein considered as vas deferens vein was actually an internal spermatic vein. Case_2 : A 28-year-old male patient complained of recurrence of varicocele two months after the original operation for a grade 3 varicocele. Internal spermatic vessels were slightly visualized on retrograde venography. The possible cause of persistence in this case was insufficient ligation of the internal spermatic vessels. We performed embolization in both cases of recurrent varicocele. Both cases were successfully treated, and there has been no recurrence. Our findings suggest that percutaneous transcatheter embolization of the testicular vein may be effective in the management of postsurgical recurrent varicocele of the testis.

Purpose: To investigate the current status of interventional radiology (IR) procedures for a type II endoleak (T2EL) in Japan, and to identify the technical aspects that affect treatment results., Materials and Methods: A retrospective survey was conducted by distributing questionnaires to 25 institutions. The eligibility criteria were endovascular aortic repair (EVAR) performed using commercial stent grafts and IR performed for T2EL between January 2007 and December 2013. Technical success was defined as disappearance of the EL on digital subtraction angiography immediately after embolization, and imaging success was defined as no EL on contrast-enhanced computed tomography within 6 months. Statistical comparisons of the number of involved branches, embolization level, embolic material, and changes in aneurysm size were made between the imaging success and imaging failure groups. The technical and imaging success rates were also compared between the initial therapy and repeat groups., Results: A total of 166 cases were investigated. Initial therapy was performed in 147 cases (88.6 %), with repeat therapy in 19 cases (11.4 %). Transcatheter arterial embolization (TAE) was used most frequently, in 161 cases (97 %), with direct puncture (DP) used in 5 cases (3 %). Both coil embolization for the branches and NBCA embolization for the sac were frequently chosen. The technical success rate was 83.2 % (TAE group), and the imaging success rate was 46.5 % (TAE + DP groups). Branch + sac embolization was performed more frequently in the imaging success group. There was no significant difference in the number of involved branches or embolic material between the imaging success and imaging failure groups. Enlargement of the aneurysm was more frequently seen in the imaging failure group. There were no significant differences in the technical success and imaging success rates between the initial therapy and repeat groups., Conclusion: This is the first report of a multi-institutional questionnaire survey of IR procedures for T2EL after EVAR in Japan that was conducted to determine the current status. Enlargement of aneurysm size after embolization was more frequently seen in the imaging failure group. It is important to embolize both branch and sac to achieve imaging success, regardless of embolic material. Long-term outcomes need to be investigated.

Purpose: To evaluate the feasibility and safety of transarterial embolization (TAE) using trisacryl gelatin microspheres (TGMs) for hypervascular tumors., Materials and Methods: This was a prospective multicenter clinical trial involving five institutions. TAE using TGMs was performed for hypervascular tumors in various locations. The primary endpoint was the technical success. The secondary endpoints included catheter accessibility, preservation of the feeding arteries, local tumor response based on the Response Evaluation Criteria in Cancer of the Liver (RECICL) and adverse events related to TAE based on the Common Terminology Criteria for Adverse Events, version 4.0., Results: Twenty-three patients with liver tumors (n = 9), uterine fibroids (n = 3) and other tumors (n = 11) were enrolled. The technical success rate was 95.7 % (22 of 23 patients). Catheter accessibility and preservation of the feeding arteries were obtained in all 55 target vessels (100 %). Local tumor response rates were 46.7 and 55.8 % at 4 and 12 weeks, respectively. Eighteen (78.3 %) patients developed 53 symptomatic events including grade ≧3 events: hypertension 21.7 %, pain 8.7 %, vomiting 4.3 % and anorexia 4.3 %, all related to postembolization syndromes., Conclusion: TAE using TGMs was technically feasible and safe for devascularization of hypervascular tumors.

Purpose: To determine the arterial distribution and ischemic effects of various particle sizes after transcatheter embolization of the small bowel in a dog model., Materials and Methods: In 10 dogs, selective microsphere embolization was performed in six branches of the superior mesenteric artery. Microspheres were allocated into three size ranges (100-300 μm, 300-500 μm, and 500-700 μm) and four volume concentrations (0.625%, 1.25%, 2.5%, and 5%). For each size and volume concentration, embolization was performed of five branches at the origin of the last arcade. The distribution of microspheres and the range of ischemic changes of mucosa were evaluated histologically. Angiograms were categorized into two groups: group A, only the vasa recta nonopacified; group B, the last arcade or more proximal branches nonopacified., Results: Microspheres sized 100-300 μm penetrated into intramural arteries and 500-700 μm microspheres mainly blocked arteries in the mesentery. There was a significant difference among three sizes in terms of the locations within the vasculature (P < .0001). The larger volume and the smaller size resulted in more ischemia. The range of ischemic changes among three sizes and among four volume concentrations was significantly different (P = .004 and P < .0001, respectively). The range of ischemic changes with 500-700 μm microspheres in group B was significantly greater than in group A (0% in group A vs 83% in group B, P = .001)., Conclusions: In a dog model, embolization of the small bowel limited to the vasa recta with the use if 500-700 μm microspheres reduced the range of ischemic changes., (Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the correlation between packing density and the incidence of coil compaction or recanalization of visceral artery aneurysms (VAAs) after coil packing., Materials and Methods: Between July 2004 and April 2012, coil packing was performed for 46 true visceral aneurysms (16 splenic, 11 pancreaticoduodenal, eight renal, six hepatic, three superior mesenteric, one right gastric, and one gastroepiploic) in 42 patients. The size and volume of the aneurysm, packing density, and the incidences of compaction and recanalization were evaluated retrospectively., Results: The mean follow-up period was 37 months ± 8 (range, 11-80 mo). The mean packing density was 19% ± 8 (range, 5%-42%), mean aneurysm size was 19 mm ± 8 (range, 5-40 mm), and mean volume was 4,108 mm(3) ± 5,435 (range, 72-26,235 mm(3)). Compaction and recanalization occurred in two (4%) and 12 aneurysms (26%), respectively. The mean packing density was significantly lower in aneurysms with compaction or recanalization than in unaffected aneurysms (12% vs 22%; P = .00014). There was a significant difference in mean packing density between small (< 20 mm; 22%) and large (≥ 20 mm) aneurysms (15%; P = .0045). The mean size and volume were significantly larger for coil-compacted or recanalized aneurysms than for unaffected aneurysms (P < .05). In aneurysms with a packing density of at least 24%, no compaction or recanalization occurred., Conclusions: Coil compaction or recanalization after coil packing for VAAs more often occurs after insufficient embolization with low packing density and in patients with large aneurysms., (Copyright © 2013. Published by Elsevier Inc.)

Purpose: To 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 Methods: Eight 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., Results: REM 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., Conclusions: REM 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., (Copyright © 2013 SIR. Published by Elsevier Inc. All rights reserved.)

The present study investigates the mechanical properties of three embolization microspheres (E-ms): tris-acryl gelatin microspheres (TG-ms), acrylamido polyvinyl alcohol microspheres (APVA-ms), and polyphosphazene-coated polymethylmethacrylate microspheres (PP-PMMA-ms). Compression and relaxation tests were performed on monolayers of particles and their Young's moduli and relaxation half times (RHTs) were determined. The elasticity of E-ms was evaluated by applying Hertz theory with the assumptions of incompressibility and a Poisson's ratio of 0.5. The Young's moduli of TG-ms, APVA-ms, and PP-PMMA-ms were 39.6±5.05 kPa, 18.8±4.00 kPa, and 13.6±1.98 kPa, respectively. The RHTs of TG-ms, APVA-ms, and PP-PMMA-ms were 52.3±5.56 s, 59.1±8.16 s, and 31.0±7.01 s, respectively. TG-ms have a high rigidity and deform slightly under a sustained compression since they have a high elasticity. PP-PMMA-ms are soft and deform a lot under sustained compression. They are more viscous than the other two microspheres. APVA-ms have intermediate material properties, having the same low rigidity as PP-PMMA-ms and being more elastic than TG-ms., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Embolic agents are used in vascular interventional radiology to occlude arteries under pathological conditions. The present study was performed to investigate the material properties of two microspherical embolic agents (MSEAs), tris-acryl gelatin microspheres (TGMS) and superabsorbent polymer microsphere (SAP-MS), using a loading-unloading compression test. The results demonstrated that for both TGMS and SAP-MS, the stress-strain relationship appeared to be linear up to 25% deformation. Therefore, one can reasonably treat TGMS and SAP-MS as linearly elastic materials for this range of deformation and apply the Hertz contact theory for analysis of the Young's modulus. The Young's moduli of TGMS and the SAP-MS obtained by applying Hertz theory under the assumption of a Poisson's ratio of 0.5 were 19.33 +/- 4.97 kPa and 9.64 +/- 2.46 kPa, respectively (mean +/- SD, P<0.001, Mann-Whitney U-test), indicating that TGMS showed higher stiffness than SAP-MS. The effects of a difference in these mechanical characteristics of embolic agents on the performance of interventional radiology were discussed from a viewpoint of their flowing behavior and clinical aspects., (Copyright (c) 2010 Elsevier Ltd. All rights reserved.)

Arteriovenous fistula may be due to a vascular injury during various orthopedic surgeries. It may cause massive, unexpected bleeding during or following an operation or during rehabilitation. We report herein the case of a 48-year-old woman with a previous history of hip joint surgery due to congenital hip dislocation who experienced massive bleeding during a second operation. Postoperative pelvic angiography revealed large, complex arteriovenous fistulas with combined venous aneurysm. She was managed successfully by transarterial embolization.

Although melanoma frequently metastasizes to the liver, its spontaneous rupture is rare. We report herein an unusual case of a 73-year-old man with rupture of multiple hepatic metastases from scalp melanoma and resulting massive intraperitoneal bleeding, which was successfully controlled by transarterial embolization.

Purpose: To find appropriate contrast media to load cisplatin into superabsorbent polymer (SAP) and to analyze the absorption and elution kinetics of cisplatin to and from SAP., Materials and Methods: Three contrast media-ioxaglic acid 320 mg/mL, iohexol 300 mg/mL, and iopamidol 300 mg/mL-were tested for solubility of a new highly soluble cisplatin powder. The appropriate concentrations of cisplatin were predetermined according to the solubility in each contrast medium. For each concentration, we assessed the cisplatin elution kinetics with an atomic absorption spectrophotometer. The SAP particle diameters (106-150 microm dry size) before and after drug elution were also measured., Results: The concentrations of cisplatin were predetermined as 2.5 mg/mL in ioxaglic acid, 2.5 mg/mL in iohexol, and 5.0 mg/mL in iohexol. At these concentrations, 100 mg of SAP carried 5 mg, 25 mg, and 50 mg of cisplatin dissolved in ioxaglic acid (2.5 mg/mL) and iohexol (2.5 mg/mL and 5.0 mg/mL), respectively. Cisplatin-loaded SAP in ioxaglic acid and iohexol exhibited similar elution profiles, with cisplatin fractions of 15%, 40%, 70%, and 95% at 1, 3, 6, and 24 hours, respectively. By drug elution, the mean particle diameter changed from 0.31 mm to 0.61 mm in ioxaglic acid (2.5 mg/mL), from 0.54 mm to 0.60 mm in iohexol 2.5 mg/mL, and from 0.63 mm to 0.59 mm in iohexol 5.0 mg/mL., Conclusions: SAP was confirmed to absorb and elute cisplatin within 24 hours. When mixed with iohexol, SAP carried a ten times larger dose of cisplatin and expanded twice as large as when mixed with ioxaglic acid. Cisplatin-loaded SAP may have potential as a drug delivery system for the clinical treatment of liver tumors., (Copyright (c) 2010 SIR. Published by Elsevier Inc. All rights reserved.)

We report a case of a giant mediastinal bronchial artery aneurysm disguised as an aneurysm with multiple feeding arteries. A 74-year-old man with a history of bronchiectasis was admitted to our hospital for treatment of a bronchial artery aneurysm. Because the segment of feeding vessels between the thoracic aorta and the aneurysm was short, it was not possible to occlude the feeding artery simply by transarterial embolization. A combined procedure of stent-graft occlusion of the inflow artery and coil embolization of the outflow artery was successfully performed., (Copyright (c) 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Liver abscess formation has been recently concerned after hepatic arterial embolization using porous gelatin particles( Gelpart)(GP), and inhomogeneous particles size or fragmentation of GP may partly contribute to this complication. The purpose of this study was to investigate the size distribution and incidence of fragments of GP before and after microcatheter passage. 1 mm- and 2 mm-GP were injected into three microcatheters with different inner-diameters by three interventional radiologists. The particles were stained with methylene blue dye, and the longer- and shorter-particle diameters were measured by a digital microscope. The particles less than 300 microm and 600 microm in longer- diameter was defined as fragment for 1 mm- and 2 mm-GP, respectively. Diameter of GP showed a wide bimodal distribution by fragments and non-fragment particles. The change of mean particle diameter ranged within 10%, and the ratio of shorter- to longer-particle diameter remained similarly at 0.75. The incidence of fragments was approximately 10% and 5% before microcatheter passage and increased by one-two times and two-five times after microcatheter passage for 1 mm- and 2 mm-GP, respectively. In conclusion, GP were ununiform in particle size distribution and contained fragments. GP did not change in shape significantly after microcatheter passage, however, 2 mm-GP was more prone to fragmentation than 1 mm-GP.

The purpose of this study was to investigate the clinical outcomes of bland embolization using superabsorbent polymer microspheres (SAP-TAE) as an initial therapeutic option for previously untreated hepatocellular carcinoma (HCC) ineligible for resection or ablation. Fifty-nine patients with previously untreated HCC unamenable to surgery or ablation underwent bland embolization using 100- to 200-mum reconstituted SAP particles (SAP-TAE) as the initial treatment. SAP-TAE was repeated as needed based on tumor response but was switched to chemoembolization when necessary to control residual or progressive tumor. Early tumor response was assessed by contrast-enhanced CT according to RECIST and EASL criteria 1 month after the initial SAP-TAE. The overall survival was calculated using the Kaplan-Meier method. The overall mean follow-up period was 30.6 months (range, 7-59 months). A total of 121 sessions of SAP-TAE were performed, with 1-5 sessions per patient (mean, 2.1 sessions). The mean period of repeated SAP-TAE was 15.6 months (range, 1-51 months), and it exceeded 1 and 2 years in 32 (54%) and 15 (25%) patients, respectively. Thirteen (22%) patients underwent repeated SAP-TAE alone, and the remaining 46 (78%) patients underwent subsequent chemoembolization. No major complication was observed and postembolization syndrome was minimal after SAP-TAE in all patients. Response rate was 14% and 66% by RECIST and EASL criteria, respectively. Overall survival rates were 100% and 83% at 1 and 2 years, respectively, and median survival time was 30 months. In conclusion, SAP-TAE was a safe and repeatable option as the induction therapy for HCC unamenable to surgery or ablation, despite the high incidence of converting to TACE during the total course.

We report a case of high-flow priapism treated successfully with superselective embolization of the cavernous artery. An 18-year-old man presented to our hospital 12 days after having been struck in the perineum by the corner of a skateboard. Immediately after the injury, he suffered painless sustained incomplete erection. High-flow priapism was diagnosed on the basis of cavernosal blood gas analysis and color Doppler ultrasonography findings. Right internal pudendal arteriography showed blood pooling in the cavernosum as a result of a broken artery. We identified the precise position of the arterial-venous fistula and embolized it superselectively with gelatin sponge particles. The fistula disappeared completely. One year later, the patient's erectile function was completely restored, and there had been no recurrence of the priapism. According to the American Urological Association guidelines, conservative treatment should be attempted first for high-flow priapism. In our review of the literature, superselective arterial embolization could be an alternative treatment after more than 3 weeks of conservative treatment.

Hepatic arterial embolization (HAE) has been widely performed for unresectable hepatocellular carcinoma (HCC) in a selective manner using a microcatheter. Gelatin sponge is exclusively used as an embolic agent, though it has not yet been approved for an arterial blockade. Recently, new porous gelatin particles (GP) have been approved and are clinically available. In this study, passage of GP through microcatheters was investigated, as it is an important requirement for a new agent. Both 1-mm and 2-mm GP were injected through each of six current 2.0 Fr-2.7 Fr microcatheters by five board-certified interventional radiologists. In general, use of a 2.5 mL lock syringe was associated with higher subjective resistance score (5-10/10), longer injection time (20-30 sec), and lower injection pressure (1.0-2.5 MPa) with difficulty. When it was impossible to inject GP with a 2.5-mL lock syringe,injection was retested with a 1 mL lock syringe resulting in lower resistance score (1-6), shorter injection time (6-10 sec), and higher injection pressure (1.5-2.5 MPa) regardless of particle size. Thus,it is recommended to use a 1 mL lock syringe for injection of GP through a microcatheter. After passing through a 2.0 Fr microcatheter, 2 mm particles showed no significant deformation or fragmentation under observation by stereomicroscopy.

Transcatheter embolotherapy (TCE), a common procedure for interventional radiologists, comprises transcatheter delivery of embolic agents into target vessels in order to eliminate lesions or lesion-associated symptoms. Good knowledge of delivery catheters and embolic agents is essential to optimize embolization techniques and to obtain the desired therapeutic outcomes. In this review, we describe the principles and techniques of TCE for peripheral arterial and venous lesions featuring visceral aneurysms, peripheral and pulmonary arteriovenous malformations (AVMs), and varicoceles.

Uterine artery embolisation (UAE) has become an alternative treatment for symptomatic uterine leiomyomata. Most reports suggest that it is well tolerated and effective, although there have been no reports of studies of biological parameters after UAE. In this study, we analysed the plasma level of vascular endothelial growth factor (VEGF) and the pulsatility index (PI) of uterine arteries before and after UAE. The level of plasma VEGF increased significantly after UAE (on day 1 and day 3) and decreased on day 7, and then increased again on day 30. The level of VEGF reached a peak value within three days after UAE. A significant inverse correlation was found between uterine artery PI and the level of VEGF on day 30, suggesting that VEGF may have negative effect on the efficacy of treatment of uterine leiomyomata by UAE.

Purpose: We have developed a spherical embolic agent, superabsorbent polymer microspheres (SAP-MS). The aim of this study was to examine the embolic effects of SAP-MS in comparison with polyvinyl alcohol (PVA) particles and tris-acryl gelatin microsphere (Embosphere Microsphere; EM) in a rabbit renal model., Materials and Methods: The right kidneys of nine rabbits were embolized with the given agents: PVA (180-300 microm) (n=3), EM (100-300 microm) (n=3), and SAP-MS (106-150 microm) (n=3). The embolized kidneys were evaluated by angiography and histology after one week., Results: Renal artery occlusion and prominent coagulative necrosis were confirmed regardless of agent. PVA aggregated in the proximal vessels with tiny fragments migrating into glomeruli. Both EM and SAP-MS traveled distally up to the interlobular artery level, and a single particle achieved cross-sectional vessel occlusion. SAP-MS was markedly swollen, deformed, and conformed to the vessel lumen compared with the constantly spherical EM. Mild perivascular reaction was seen with both microspheres., Conclusion: SAP-MS resulted in targeted end-organ infarction in the rabbit renal model and showed different mechanical properties from other agents.

A prototype 0.018 pushable fibered microcoil with an extended length of 14 cm was developed and used successfully for the first time to treat a patient with bilateral varicocele. This new coil provides immediate cross-sectional occlusion when "nested" into a densely packed coil mass. Potential uses of this new microcoil are discussed.

Purpose: To determine efficacy, safety, and requirements for adjunctive embolization or surgery in the treatment of symptomatic arteriovenous malformations (AVMs) with superabsorbent polymer microsphere (SAP-MS) particles., Materials and Methods: SAP-MS particles (sodium acrylate and vinyl alcohol copolymer) are nonbiodegradable spheres with a precisely calibrated diameter. SAP-MS particles swell by absorbing fluids and become soft and deformable. Twenty-five patients (16 men, nine women; mean age, 32 y; range 12-66 y) with symptomatic facial (n = 5), upper- (n = 8) and lower- (n = 12) extremity AVMs were treated primarily (n = 23) or preoperatively (n = 2) by transarterial embolization (TAE) treatment with use of SAP-MS particles. Direct puncture embolization (DPE; n = 4) and/or surgical intervention (n = 5; ie, skin graft, resection, or amputation) were required. Surgical specimens from the resected (n = 2) and the amputated (n = 2) patients were evaluated histologically. Follow-up study, including clinical findings and imaging studies, was performed at intervals ranging from 3 months to 1 year. Clinical outcome was evaluated retrospectively, depending on the subjective improvement of symptoms and signs, according to the medical records., Results: Seventy-two TAEs (range, 1-11; mean, 2.8) and 12 DPEs (range, 1-3; mean, 2.4) were performed during the mean follow-up period of 38 months (range, 7-110 mo). Twenty patients (80%) experienced symptom improvement by embolotherapy alone (n = 17) or in combination with surgery (n = 3). One lip and two finger AVMs were totally removed by surgical excision or amputation after TAE treatment. In diffuse upper- (n = 1) and lower- (n = 1) extremity AVMs, the symptoms were uncontrolled. No nerve injury or skin necrosis was observed after TAE treatment with SAP-MS particles. Mucosal necrosis was induced by DPE with ethanol in one patient. Histologically, SAP-MS particles penetrated intralesional vessels and conformed to the vessel lumen, resulting in tight vessel occlusion. Minimal perivascular reaction was observed., Conclusion: SAP-MS particles were used safely in TAE treatment of AVM. TAE treatment with use of SAP-MS particles was suitable for certain symptomatic AVMs, but diffuse AVMs remain a challenge and a combination of alternative methods will be necessary for further strategy.

The authors report the initial experience with transarterial embolization of large hepatocellular carcinoma (HCC) with use of superabsorbent polymer microsphere (SAP-MS) particles. Six patients with nine HCCs (mean diameter, 8.2 cm) underwent 10 embolization procedures. Two patients underwent surgery later. In follow-up, tumor necrosis, postembolization syndrome, and laboratory data were assessed. Complete necrosis in three nodules, nearly complete necrosis in three nodules, and partial necrosis in three nodules were observed. Histologically, SAP-MS occluded intratumoral vessels tightly without ischemic damage of normal hepatic tissue. Postprocedural pain was minimal. No deterioration of liver function occurred. Our initial experience suggests that embolization with use of SAP-MS leads to extensive tumor necrosis of large nodular HCC, sparing use of chemotherapeutic agents.