Embosphere Particles Research Articles

Comparison of adjunctive middle meningeal artery embolization using embosphere particles versus surgical drainage alone for the treatment of chronic subdural hematoma: A prospective study

BackgroundMiddle meningeal artery embolization (MMAE) has emerged as a primary and adjunctive therapy for chronic subdural hematoma (CSDH) in addition to conventional treatment. However, there is a scarcity of data that explicitly compares the effectiveness of adjunctive MMAE to surgical drainage alone (SDA), as well as the use of Embosphere particles. The objective of this study was to assess the safety and efficacy of adjunctive MMAE in the treatment of symptomatic CSDH compared to SDA. MethodsThis prospective study included 43 patients with 52 CSDH sides, treated at a single institution between 2022 and 2023. The primary outcome was postoperative hematoma volume at 14, 30, 90, and 180 days after surgical drainage, which was analyzed using the generalized estimating equation. The secondary outcomes were the complications and recurrence/reoperation rate. Adjunctive MMAE was performed within 7 days following the surgery, utilizing Embosphere as the embolic material. ResultsThe patients were assigned to either the adjunctive MMAE group (n = 20, 26 CSDH sides) or the SDA group (n = 23, 26 CSDH sides). The adjunctive MMAE group demonstrated a more significant reduction in hematoma volume (p = 0.007) and maximal hematoma thickness (p = 0.016) at all follow-up intervals. A trend towards lower recurrence and reoperation rates was observed with adjunctive MMAE; particularly, none of the patients in the adjunctive MMAE group experienced a recurrence of CSDH, compared to 19.2 % in the SDA group (p = 0.051). One procedural-related complication (3.8 %) in the adjunctive MMAE group. ConclusionOur results suggested that adjunctive MMAE, compared to SDA, may enhance hematoma resolution and reduce the need for reoperation due to recurrence.

Abstract No. 163 Feasibility of pancreatic particle embolization: a proof of safety study in a porcine model

Although particle embolization is a common treatment of hypervascular neuroendocrine metastases of the liver, this treatment is not considered an option for the originating pancreatic neuroendocrine tumor(s) due to theoretical concern for pancreatitis. The purpose of this study was to explore the safety of pancreatic embolization in a porcine model. Approval for this study was obtained from the Institutional Animal Care and Use Committee. A total of 6 domestic swine weighing between 90 and 110 pounds were obtained. A single nonsurvival animal underwent infusion of methylene blue dye into the dorsal pancreatic artery using a microcatheter followed by particle embolization to stasis using 100-300 μm Embosphere particles to confirm technical feasibility. Immediate laparotomy confirmed blue staining of pancreatic parenchyma without evidence of non-target embolization. Five survival animals underwent baseline serum lipase level assay, and particle embolization of the dorsal pancreatic artery was performed under general anesthesia. Animals were observed postoperatively for one week with monitoring of behavior, activity, food intake, and observation for signs of pancreatitis. After one week, repeat serum lipase was obtained, the animals were euthanized, and their pancreata excised for gross pathologic analysis. Technical success with embolization was achieved in all study animals. In the five survival animals that were monitored after embolization, behavior, activity levels and food intake returned to baseline by postoperative day #1. All animals survived to 7 days without signs or symptoms of significant pain, systemic infection or decline. There was no significant change in serum lipase levels comparing pre-procedure to day 7, with average serum lipase levels of 56.8 U/L and 40.2 U/L, respectively. At necropsy, regions of lobular expansion and discoloration were identified in all pancreata that are compatible with inflammation. These findings suggest that particle embolization of the dorsal pancreatic artery in swine is technically feasible and results in adequate ischemia to cause inflammation of target pancreatic tissues, but without biochemical signs of pancreatitis, systemic sequelae, or mortality after one week of observation. Based on this early data, further evaluation of particle embolization of the pancreas in animal models may be justified to further clarify safety and physiologic sequelae.

Bronchial Artery Embolization with Large Sized (700-900µm) Tris-acryl Microspheres (Embosphere) for Massive Hemoptysis: Long-Term Results (Clinical Research).

To investigate the safety, efficacy and long-term results of bronchial artery embolization with microsphere particles (Embosphere® Microspheres, BioSphere Medical, Rockland, MA) 700-900µm in size for massive hemoptysis. One hundred and seventy-four patients (94 female, 80 male; mean age 39.4±5.7) who had bronchial artery embolization for massive hemoptysis between January 2010 and October 2015 were incorporated in the study. Patients had hemoptysis with a mean volume of 525±150mL (median 500mL, range 300-1200mL) over a 24-h period. Underlying pathologies included bronchial artery hypertrophy due to bronchiectasis (56.3% [98/174]), lung cancer (29.9% [52/174]), tuberculosis (10.3% [18/174]) and the rest remained idiopathic (3.4% [6/174]). Mean bronchial artery diameter before the intervention was 3.8±1.5mm (median 4mm, range 3.1-7.5mm). Median follow-up period was 56months (range 10-82months). Primary objectives were the technical and clinical success. Technical success was 100%. Clinical success for preventing massive hemoptysis was 91.9% (160/174). There was no procedure-related mortality or morbidities. Minor complications such as chest pain were observed in nine patients (5.0%). Recurrent hemoptysis (8.1%) was observed within 6months in 14 patients, ten of whom were treated with a second embolization session and the remaining four with a total of three embolization sessions. Bronchial artery embolization for massive hemoptysis with Embosphere particles 700-900µm in size is a safe and effective method with high technical and clinical success rates. Long-term results are excellent.

3:00 PMAbstract No. 326 - Selective geniculate artery embolization for management of recurrent hemarthrosis after knee arthroplasty

PurposeSpontaneous recurrent hemarthrosis occurs in up to 1.6% of patients following total knee arthroplasty, most often related to hypervascular proliferative synovium and associated component impingement, making the synovium prone to trauma and bleeding. Hemarthrosis may result in poor arthroplasty function or failure. When conservative management fails, targeted geniculate artery embolization (GAE) can serve as a treatment alternative to synovectomy. We present a single institutional experience with GAE for recurrent hemarthrosis in the setting of prior knee arthroplasty.MaterialsAll GAE performed in patients with clinical and/or imaging findings of recurrent hemarthrosis post knee arthroplasty between July 2003 and September 2015 were included in this study. Iatrogenic pseudoaneurysms were excluded. Patient demographics, embolic agent, technical success, procedure time, and immediate complications were ascertained. Imaging and clinical follow-up data was reviewed.Results46 GAE performed in 35 patients (17 male, 18 female; mean age 67, range 41-83 years) met inclusion criteria. Intraprocedural angiography demonstrated focal synovial hyperemia in 100% of cases. Embosphere particles were used in all but one case where microcoils were used. Particle size ranged from 100-700 um, 93% of cases utilizing solely 100-300 um particles. Embolization was technically successful in all cases. Postembolization angiograms demonstrated diminished or absent synovial hypervascularity in all cases. Periprocedural transient cutaneous ischemia occurred in 11%. Postprocedural follow-up was available for 25 cases with a mean follow-up interval of 70 days (range 1-413 days), with 23 (92%) exhibiting clinical improvement of symptoms. 11 repeat GAEs were performed in 9 patients experiencing recurrence or persistence of symptoms. Of these, review of initial post GAE angiogram revealed residual synovial blush in 10 (91%).ConclusionsTargeted GAE with spherical particles is an effective treatment for recurrent hemarthrosis following knee replacement with low immediate complication rates. Residual focal hyperemia on immediate postembolization angiogram may be associated with clinical recurrence or persistence.

Splenic embolization as an alternative to surgical splenectomy for the restoration of blood counts suitable for effective chemotherapy in gastrointestinal malignancies (GIM).

396 Background: Chemotherapy regimens used for GIM are often notably myelosuppressive and may also engender hypersplenism. This can result in platelet (plt) and/or absolute neutrophil counts (ANC) too low for the maintenance of required dose intensity or frequency. One successful approach to this problem is surgical splenectomy but this is both morbid and invasive. An alternative strategy uses super-selective embolization of the splenic arterial tree, which is performed as an outpatient, and is far better tolerated. The true efficacy of this technique is uncertain and the optimal patients (pts) for this procedure are not well defined. Methods: Between 11/2012 and 6/2015, pts with ECOG PS 0/1 currently on active therapy for GIM in our clinics, whose plts and/or ANC were consistently below threshold values for appropriate frequency or intensity of therapy, were referred to Interventional Radiology for splenic embolization. Selective catheterization of the splenic artery was achieved via a femoral approach. This was followed by super-selective catheterization of branches of the splenic artery, as distally as possible, with subsequent embolization using Embosphere particles (300-500 micron spheres). All pts received prophylactic IV antibiotics. Results: 10 pts were identified and referred and all were deemed suitable for embolization. The mean plt count prior to the procedure was 73,000 (39,000-167,000) and the mean ANC was 3.5 (1.3 – 5.3). Following one procedure in 9 pts and 2 procedures in 1 pt, the mean plt count rose to 175,000 (55,000-432,000) and the ANC to 7.2 (2.9 – 13.2) immediately, and to a maximum of 253,000 (76,000-511,000) and 9.3 (5.0 – 14.5) within one to two months.Splenic enlargement was noted in 6 pts (mean size 18.3 cm) prior to the procedure and was not present in 4 pts. Following embolization all patients were able to resume chemotherapy with previously effective doses and/or frequency. Conclusions: In our cohort of pts with GIM, splenic embolization was successful at restoring acceptable plt and/or ANC levels for the resumption of effective chemotherapy. Splenomegaly does not appear to be a prerequisite for success.

Practical Tantalum Coating of Microspheres for Experimental Visualization under Fluoroscopy and CT

The present report describes a simple technique for tantalum coating of microspheres for visualization by fluoroscopy and computed tomography (CT). Spherical microspheres were soaked with Ta powder under different conditions and microscopically evaluated for Ta-coating quality by assessing bound and unbound Ta. For 100–300-µm Embosphere particles, soaking with 0.05 mL Ta powder for 30 minutes and centrifugation at 500 rpm produced optimal coating. Optimized microspheres were injected in swine renal arteries and assessed by fluoroscopy and micro-CT for the opacification of segmental, arcuate, and interlobular arteries. This practical method can be used for experimental studies with commonly available microspheres.

Transarterial prostatic embolization:initial experience in hormone-induced benign prostatic hyperplasia in dogs

Objective To evaluate the feasibility of transarterial prostate embolization for reducing the volume and its technical safety in hormone-induced dogs prostate hyperplasia. Methods Prostate hyperplasia was induced on 12 adult male dogs by administering testosterone propionate for 12 weeks.Then,the dogs were randomly assigned to transarterial prostatic embolization group (n=6) and control group (n=6).Twelve weeks after initiating the hormone treatment,6 animals in transarterial prostatic embolization group underwent prostatic arterial embolization with Embospheres 100—300μm in diameter.Based on MRI,the volume of prostate was measured for both groups on the three time points: before injection of hormone (BI),before the procedure of prostatic arterial embolization (BP) and 12 weeks after the procedure of prostatic arterial embolization (AP).Finally,the prostates and surrounding tissues were harvested for histopathology study.A statistical software package (SPSS version 19.0) was used for analysis.Measurement data were expressed as x± s.Samples paired t test was used to compare the prostatic volume between BP and AP.The t test was applied in the intergroup comparison.P<0.05 was considered to indicate a statistically significant difference. Result s The successful rate of BPH model establishment and superselective catheterization were 100%.No serious procedure-related complication was observed.After 12 weeks of hormone administration,the mean volume of prostate was 19.5±2.5 mm3in embolization group and 19.2±3.8 mm3in control group before prostatic arterial embolization,without statistical difference (t=0.14,P>0.05).At 12 weeks after prostatic arterial embolization,the mean volume of prostate was 6.1±1.4 mm3in embolization group and 17.8±3.5 mm3in control group with significant statistical difference (t=-7.6,P 0.05).Histopathology study revealed that embosphere particles had occluded partial arterioles of the prostate in the embolization group of dogs.Near the occluded arterioles,normal gland structure disappeared; while residual gland tissue appeared to be atrophied.In embolization group,there was no gross or microscopic change in the surrounding tissues including bladder,deferent duct and rectum.Extensive prostate glandular hyperplasia was observed in control group. Conclusions Transcatheter arterial embolization is feasible for reducing prostate volume without serious complication in hormone-induced prostate hyperplasia dogs and worthy of further investigation. Key words: Prostatic hyperplasia; Embolization,therapeutic; Angiography,digital subtraction;Animals,laboratory

A Pilot Study of Uterine Artery Embolization with Tris-Acryl Gelatin Microspheres in Guinea Pigs

This study was designed to establish guinea pigs as an animal model for uterine artery embolization (UAE) with tris-acryl gelatin microspheres (TAGM). Twenty-five female adult guinea pigs were randomly divided into two groups, including a uterine artery casting mould group (n=10) and a UAE group (n=15). Pelvic angiography and vascular casting mould were performed in the first group. The anatomical characters of the pelvic cavity in guinea pigs were described. In the second group, the technical feasibility of performing UAE with TAGM in guinea pigs was investigated. The histopathological slides of the uterus of guinea pigs after UAE were examined to inspect the outcomes of UAE. The uterine artery springs from the internal iliac artery, ascends tortuously along the cervix, and gives off vertically 8-10 branches to the cervix uteri and uterine horns. The diameters of the trunk of the uterine artery and its first branch were 0.32±0.027 mm and 0.14±0.01 mm, respectively. For UAE animals, the dosages of 40-120 and 100-300 μm TAGM were 0.033±0.003 ml and 0.015±0.002 ml, respectively. On histopathological slides, embosphere particles were found in the first branches of the uterine artery, the subserous arteries, and the intramural arteries. Inflammatory reactions in the uterus were common in guinea pigs after UAE. Local or dispersed areas of necrosis in uterus also were observed in a few guinea pigs. Guinea pigs are an appropriate and feasible model for UAE with TAGM.

Transarterial Chemoembolization with Epirubicin-eluting Beads versus Transarterial Embolization before Liver Transplantation for Hepatocellular Carcinoma

To retrospectively compare radiologic tumor response and degree of necrosis in explanted livers after chemoembolization with epirubicin-loaded DC Bead versus bland embolization in patients on a transplant waiting list. From 2003 to 2007, 49 patients with hepatocellular carcinoma (HCC) underwent transplantation at a single center. Sixteen patients were treated with bland embolization (n = 8) with 100-300-microm Embosphere particles or chemoembolization with epirubicin-loaded 100-300-microm DC Bead particles (n = 8) every other month until complete tumor devascularization. Computed tomography was performed every 3 months until recurrence. Explanted livers were analyzed to evaluate the degree of necrosis in the nodules. After orthotopic liver transplantation (OLT), patients were followed up for survival and disease status. The groups were comparable for baseline characteristics. Most patients had Child-Pugh class A disease. Solitary HCC was found in 75% of patients. Mean target lesion size was 32 mm +/- 15.4. Chemoembolization with drug-eluting beads achieved complete necrosis in 77% of lesions whereas bland embolization achieved complete necrosis in 27.2% of lesions. There was a significant difference between bland embolization and chemoembolization with DC Bead with regard to histologic necrosis (P = .043). No significant treatment-related complications were observed for either group. Fifteen patients are alive with no tumor recurrence. Chemoembolization with drug-eluting beads before OLT achieved higher rates of complete histologic response than bland embolization, with no serious adverse events observed. Because of the retrospective data analyses and small sample size, further studies are warranted to confirm these promising results.

Arterial Distribution Characteristics of Embozene Particles and Comparison with Other Spherical Embolic Agents in the Porcine Acute Embolization Model

To determine the arterial distribution pattern of the embolic agent Embozene within the porcine kidney and compare it with those of other spherical embolic agents. Embozene, Embosphere, Bead Block, and Contour SE in size classes of 100-300 microm, 500-700 microm, and 700-900 microm and Embozene and Embosphere in the size class of 40-120 microm were used for total arterial occlusion in minipig kidneys. Organs were evaluated microscopically regarding vascular distribution of the different embolic agents and particle sizes. The following variations of arterial distribution were identified. In the 40-120-microm size class, Embosphere particles penetrated significantly deeper compared with Embozene (P = .04). In the 100-300-microm size class, Bead Block showed a significantly deeper distribution as microscopy identified particles in arteries much smaller than their nominal size. In the 500-700-microm size class, Embosphere and Contour SE showed a deeper distribution. The most uniform arterial distribution was observed in the 700-900 microm size class,. However, few Embosphere and Contour SE particles were found in arcuate arteries, also indicating a distal distribution. Throughout the four most-used size classes, from very small (40-120 microm) to large (700-900 microm), the distribution characteristics of the four tested materials vary substantially. Particularly, small Embosphere particles and small Bead Block particles showed a more distal distribution, as did medium-sized Embosphere and Contour SE particles. In the largest investigated size class, the distribution was more uniform. In general, the Embozene particles are very uniform in size, and they seem to reach vessels closely corresponding to their nominal size.

Mediastinal Castleman Disease: Embolization without Surgery

Mediastinal Castleman Disease: Embolization without Surgery

Immunohistochemical Characterization of Specific Inflammatory Tissue Reactions following Embolization with Four Different Spherical Agents in the Minipig Kidney Model

To evaluate the immunohistochemical inflammatory reaction after porcine renal embolization with the new spherical embolic agent Embozene and to compare it with other spherical embolic agents. After superselective porcine renal embolization (40 pigs) with different sizes of embolic agents (Embozene, Embosphere, Bead Block, Contour SE), tissue arrays were obtained (size ranges, 40-120 microm, 100-300 microm, 500-700 microm, 700-900 microm). After immunostaining for CD subtyping (CD45 and CD68) and cytokines (C-reactive protein [CRP] and interleukin-1 beta), a semiquantitative immunoreactivity score was calculated for each marker: intensity of staining was scored between 0 (negative) and 3 (intensive) and extent of staining between 0 and 4 (>80%), indicating the percentage of positive staining. The intensity score (0-3) was multiplied by the extent of staining score (0-4), resulting in a semiquantitative immunoreactivity score (0-12). Analysis of cellular expression profiles (ie, CD45, CD68) revealed a significantly higher inflammatory score 4 weeks after embolization with Embosphere 100-300 microm particles than after embolization with Embozene, Bead Block, and Contour SE. After 12 weeks, the Embosphere 100-300 microm score decreased. Analysis of CRP expression showed similar results, with a significantly higher score 4 weeks after embolization with Embosphere 100-300 microm. In the size class used most frequently for uterine artery emboliation (500-700 microm), all scores were low (<2.5) and there was no significant difference among particle types. Pronounced immunomarker expression was seen 4 weeks after embolization with small Embosphere particles. However, in general, modern spherical embolic agents cause a fairly low level of inflammatory reaction. In the present experimental setting, which is highly sensitive for specific tissue-to-agent reactivity, Embozene presented with low inflammatory results.

Experimental Liver Embolization with Four Different Spherical Embolic Materials: Impact on Inflammatory Tissue and Foreign Body Reaction

We sought to describe and compare material specific inflammatory and foreign body reactions after porcine liver embolization with spherical embolic agents. In 40 animals, superselective liver embolization was performed with four different spherical embolic agents of various sizes: 40-120 microm (Embozene, Embosphere), and 100-300 microm, 500-700 microm, and 700-900 microm (Embozene, Embosphere, Bead Block, and Contour SE, respectively). After 4 or 12 weeks, inflammatory reactions were evaluated microscopically according to the Banff 97 classification. For investigation of foreign body reactions, a newly designed giant cell score was applied. Banff 97 and giant cell scores closely correlated. At 4 weeks, small Embosphere particles (100-300 microm) had a significantly higher Banff 97 score than Embozene, Bead Block, and Contour SE of the corresponding size. After 12 weeks, the calculated differences were not statistically significant. Comparison between the 4-week results and the 12-week results revealed a statistically higher Banff 97 score for Embosphere 100-300 microm after 4 weeks than after 12 weeks (P = 0.02). The overall foreign body reaction was pronounced after embolization with smaller particles, especially in small Embosphere particles. Giant cell numbers with Embosphere 100-300 microm were statistically higher compared with the other materials of corresponding size (P < 0.0001). Inflammatory and giant cell reactions after embolization procedures depend on the embolic material. The overall inflammatory reaction was low. However, marked inflammation was associated with small Embosphere particles at 4 weeks, a finding that might be caused by the allogeneic overcoat. Correspondingly, giant cells indicating a foreign body reaction were more frequently associated with small particle sizes, especially after embolization with small Embosphere particles.

Comparative Study of Four Different Spherical Embolic Particles in an Animal Model: A Morphologic and Histologic Evaluation

To perform a study in a porcine model comparing four different spherical embolic particles in terms of postembolization patency, deformation, and potential for recanalization, with a focus on a relatively new agent--HepaSphere. Partial embolization of both kidneys was performed in 18 pigs. Nine animals were sacrificed at 48 hours and nine at 4 weeks. In the same animal, the right kidney was embolized with HepaSphere particles ("dry" size, 50-100 microm; presumed final size, 200-300 microm), and the left kidney was alternatively embolized with EmboSphere (100-300 microm), Contour (150-350 microm), or Bead Block (150-350 microm) particles. The authors analyzed the size, deformation, and number of particles in each vessel, their morphologic characteristics, and recanalization. Particle sizes and deformation (1,096 particles) were as follows: HepaSphere, 225.3 microm +/- 67 and 26% +/- 19.7, respectively; EmboSphere, 132.9 microm +/- 36 and 18.1% +/- 14.2; Bead Block, 108.1 microm +/- 38 and 16.5% +/- 13.9; and Contour, 240.8 microm +/- 135 and 55.5% +/- 33. HepaSphere and Bead Block particles were distally located, and EmboSphere and Contour particles were located more proximally. EmboSphere and Bead Block particles were round, HepaSphere particles were round and/or ovoid, and Contour particles had an amorphous aspect. EmboSphere particles had a higher tendency to aggregate. No recanalization was seen with HepaSphere particles, and variable recanalization was observed with the others. Despite similar initial morphologic characteristics, the performance of the agents tested in this study differed in terms of final size, shape, deformation, and luminal recanalization. These differences have potential clinical relevance, and the knowledge of the differing embolic performance may be helpful in choosing agents for specific therapeutic purposes.

P.349 Surgical treatment for stages I and II tongue carcinoma

To evaluate the pattern of recanalization and specific inflammatory reaction after superselective embolization with four commercially available spherical embolic agents of different sizes in the mini pig kidney model.In 40 mini pigs, the lower poles of both kidneys were superselectively embolized with Embozene, Embosphere, Bead Block, and Contour SE particles in sizes of 40–120 μm (Embozene, Embosphere) and 100–300 μm, 500–700 μm, and 700–900 μm (Embozene, Embosphere, Bead Block, Contour SE). After a follow-up time of 4 or 12 weeks, recanalization was determined with angiography. Pathologic and histologic evaluation of the kidneys was performed, and the Banff 97 classification was used to evaluate the extent of vessel wall inflammation. Macroscopically visible ischemic changes were evaluated by using a specific ischemia score.After embolization with Embozene microspheres, larger Embosphere particles, and Bead Block and Contour SE particles, the absence of inflammation or a low inflammation score was observed. Significantly elevated inflammation scores were evident with small Embosphere particles after 4 weeks (mean score, 1.21 ± 1.0). Distinct recanalization occurred with Contour SE particles (100% recanalization with 100–300-μm particles at 12 weeks, 500–700-μm particles at 4 and 12 weeks, and 700–900-μm particles at 4 weeks). Ischemia scores were highest in the target area in all specimens. Mildly elevated ischemia scores in nontarget tissue areas were indicative of minor nontarget embolization.Except for small Embosphere particles at 4 weeks, the absence of inflammatory reaction to the embolization procedure or only low inflammatory changes were observed with all embolic agents, particle sizes, and follow-up intervals. Recanalization was evident with all embolic agents; however, it was pronounced with Contour SE particles.

Distribution of Iron Oxide–containing Embosphere Particles after Transcatheter Arterial Embolization in an Animal Model of Liver Cancer: Evaluation with MR Imaging and Implication for Therapy

To test whether different-sized iron oxide-containing Embosphere (IOE) particles can be detected by dedicated magnetic resonance (MR) imaging when injected intraarterially in an animal model of liver cancer and whether their distribution could be accurately predicted by MR imaging before confirmation with histopathologic analysis. Twenty New Zealand White rabbits implanted with VX2 liver tumor were randomly assigned to undergo embolization with 100-300-microm particles (group S; n = 10) or 300-500-microm particles (group L; n = 10). Embolization was performed with the catheter placed in the proper hepatic artery. T2*-weighted multiplanar MR imaging was performed within 24 hours after the procedure to detect paramagnetic IOE susceptibility artifact. MR imaging interpretation parameters included presence of artifact in the artery and/or at the tumor bed. Hematoxylin and eosin- and Prussian blue-stained pathologic slides were also obtained and the presence of IOE was evaluated similarly. The MR detectability rates for IOEs were 100% in both groups. Paramagnetic susceptibility IOE artifact inside the tumor was detected in 30% of group S animals. On pathologic analysis, IOE particles were detected inside the tumor in 70% of this group. IOEs in group L were found outside the tumor within the hepatic artery on MR imaging and histopathologic study (P < .05). MR imaging readily detected IOE particles in an animal model of liver cancer regardless of the particle size. The smaller particles (100-300 microm) were delivered inside the tumor or in close proximity to the tumor margin, justifying their use for drug delivery or precise embolization.

Embolization of Hemangioblastomas

Object. In this study the authors compare the clinical outcomes after particle embolization of hemangioblastomas in the cerebellum and spinal cord. They also review the literature of similar cases. Methods. Seven patients with hemangioblastomas in the spinal cord (four patients) and cerebellum (three patients) underwent preoperative embolization at the authors' center. Magnetic resonance imaging and selective angiography studies as well as histological diagnoses were available in all patients. Embosphere particles (trisacryl gelatin microspheres) were used in all cases. The smallest particle diameter ranged from 100 to 300 μm at the beginning of embolization in all patients. The outcome of embolization was favorable in patients with spinal cord hemangioblastomas, but it was unfavorable for those with cerebellar hemangioblastomas; acute tumor bleeding and death occurred in all of the latter cases. The outcomes following embolization are very different for these two locations possibly because of the different capillary sizes. Conclusions. The authors no longer use particle embolization to treat cerebellar hemangioblastomas.

Inflammation and Recanalization of Four Different Spherical Embolization Agents in the Porcine Kidney Model

To evaluate the pattern of recanalization and specific inflammatory reaction after superselective embolization with four commercially available spherical embolic agents of different sizes in the mini pig kidney model. In 40 mini pigs, the lower poles of both kidneys were superselectively embolized with Embozene, Embosphere, Bead Block, and Contour SE particles in sizes of 40-120 mircom (Embozene, Embosphere) and 100-300 microm, 500-700 microm, and 700-900 microm (Embozene, Embosphere, Bead Block, Contour SE). After a follow-up time of 4 or 12 weeks, recanalization was determined with angiography. Pathologic and histologic evaluation of the kidneys was performed, and the Banff 97 classification was used to evaluate the extent of vessel wall inflammation. Macroscopically visible ischemic changes were evaluated by using a specific ischemia score. After embolization with Embozene microspheres, larger Embosphere particles, and Bead Block and Contour SE particles, the absence of inflammation or a low inflammation score was observed. Significantly elevated inflammation scores were evident with small Embosphere particles after 4 weeks (mean score, 1.21 +/- 1.0). Distinct recanalization occurred with Contour SE particles (100% recanalization with 100-300-microm particles at 12 weeks, 500-700-microm particles at 4 and 12 weeks, and 700-900-microm particles at 4 weeks). Ischemia scores were highest in the target area in all specimens. Mildly elevated ischemia scores in nontarget tissue areas were indicative of minor nontarget embolization. Except for small Embosphere particles at 4 weeks, the absence of inflammatory reaction to the embolization procedure or only low inflammatory changes were observed with all embolic agents, particle sizes, and follow-up intervals. Recanalization was evident with all embolic agents; however, it was pronounced with Contour SE particles.

Hemorrhage after particle embolization of hemangioblastomas: comparison of outcomes in spinal and cerebellar lesions

In this study the authors compare the clinical outcomes after particle embolization of hemangioblastomas in the cerebellum and spinal cord. They also review the literature of similar cases. Seven patients with hemangioblastomas in the spinal cord (four patients) and cerebellum (three patients) underwent preoperative embolization at the authors' center. Magnetic resonance imaging and selective angiography studies as well as histological diagnoses were available in all patients. Embosphere particles (trisacryl gelatin micro-spheres) were used in all cases. The smallest particle diameter ranged from 100 to 300 microm at the beginning of embolization in all patients. The outcome of embolization was favorable in patients with spinal cord hemangioblastomas, but it was unfavorable for those with cerebellar hemangioblastomas; acute tumor bleeding and death occurred in all of the latter cases. The outcomes following embolization are very different for these two locations possibly because of the different capillary sizes. The authors no longer use particle embolization to treat cerebellar hemangioblastomas.

Liver embolization with trisacryl gelatin microspheres (embosphere) in patients with neuroendocrine tumors

To report our experience of liver embolization with trisacryl gelatin microspheres (Embospheretrade mark) in patients with metastatic neuroendocrine tumors. Fifteen patients underwent selective embolization of the right or left hepatic artery with Embosphere. One lobe was embolized in seven patients and both lobes, on separate occasions, in eight patients. Seven patients had midgut carcinoids, two had lung carcinoids, one suffered from a thymic carcinoid, and five had endocrine pancreatic tumors. Eight patients suffered from endocrine symptoms, seven of whom had carcinoid syndrome and one WDHA (watery diarrhea, hypokalemia, achlorhydria) syndrome. Partial radiological response was seen after eight embolizations (in six different patients), stable disease was observed after 13 embolizations (after three of these, necroses occurred), while radiological progression was noted after only two embolizations. Only two patients experienced a biochemical response. Clinical improvement of carcinoid syndrome was observed after five embolizations. There were no major complications. Fever >38 degrees C was seen after all but four embolizations, and urinary tract infections were diagnosed after eight embolizations. Selective hepatic artery embolization with Embosphere particles is a safe treatment for patients with metastatic neuroendocrine tumors and may lead to partial radiological response as well as symptomatic improvement of disabling endocrine symptoms.