Effects of endothelial injury on the rate of thrombus organization in canine carotid arteries occluded with microcoils.

SUMMARY: Thrombus organization in canine carotid arteries occluded with platinum microcoils was studied to determine if endothelial injury created with a Xenon Chloride Excimer Laser (XEL) could acclerate endovascular fibrosis. Ten common carotid artery stumps were created in ten dogs. Each of four stumps were schematically divided into four longitudinally contiguous injury zones (thermal ablation injury, non-ablative injury, proximal and distal non-injury zones) to test the effects of ablative and non-ablative injury and to establish a set of internal controls that would account for proximity to circulating blood at the ostium of the occluded artery. Following XEL irradiation of the endothelium through an arteriotomy, each stump was embolized with microcoils. Four control stumps were subjected to sham laser procedures, and embolized in an identical fashion. Two additional stumps were embolized in the absence of sham surgery. Angiographic, gross and histologic analysis was performed after four weeks. Specimens of freshly clotted whole blood mixed with microcoils were used as an additional control. In irradiated stumps and non-irradiated stumps (sham and embolization only), angiography revealed no evidence of coil compaction or recanalization. In all irradiated stumps the thermal ablation zone contained fibrous tissue and neovascularity without unorganized thrombus. The other zones in the irradiated stumps were indistingnishable from each other and from all zones in the non-irradiated sham stumps, containing primarily unorganized thrombus. Stumps embolized in the absence of sham surgery were filled with material that was grossly and microscopically identical to specimens of freshly clotted whole blood containing microcoils. The results indicate that thermal ablation injury of the endothelium accelerates thrombus organization in canine carotid arteries occluded with platinum microcoils.

Percutaneous vertebroplasty in the treatment of osteoporotic compression fractures.

Percutaneous vertebroplasty is an innovative and successful approach to the treatment of painful osteoporotic compression fractures refractory to medical therapy. We encourage all neuroradiologists to take an active interest in bringing this exciting technology to their patients and their practices.

Preoperative and palliative embolization of vertebral tumors.

Embolization of vertebral tumors is useful as an adjunct to surgery because it can minimize blood loss. Embolization also may decrease surgical operating time and reduce complications by improving visualization in the operative field. It also is occasionally useful as a palliative measure to relieve pain or neurologic compromise in patients with unresectable tumors. Spinal embolization is a relatively safe procedure when performed with proper technique by experienced operators.

Prevalence of cerebral aneurysms in patients with fibromuscular dysplasia: a reassessment.

OBJECT: The aim of this study was to determine the prevalence of cerebral saccular aneurysms in patients with carotid artery and/or vertebral artery (VA) fibromuscular dysplasia (FMD). METHODS: A metaanalysis was performed using data from 17 previously reported series of patients with internal carotid artery (ICA) and/or VA FMD that included information on the prevalence of cerebral aneurysms. In addition, the authors retrospectively evaluated their own series of 117 patients with ICA and/or VA FMD to determine the prevalence of cerebral aneurysms. The metaanalysis of the 17 earlier series, which included 498 patients, showed a 7.6 +/- 2.5% prevalence of incidental, asymptomatic aneurysms in patients with ICA and/or VA FMD. In the authors' series of patients with FMD, 6.3 +/- 4.9% of patients harbored an incidental, asymptomatic aneurysm. When the authors' series was combined with those included in the metaanalysis, the prevalence was found to be 7.3 +/- 2.2%. The prevalence of aneurysms in the general population would have to be greater than 5.6% for there to be no statistically significant difference (chi-square test, p < 0.05) when compared with this 7.3% prevalence in patients with FMD. CONCLUSIONS: The prevalence of intracranial aneurysms in patients with cervical ICA and/or VA FMD is approximately 7%, which is not nearly as high as the 21 to 51% prevalence that has been previously reported.

Hemorrhagic complications in embolization of a meningioma: case report and review of the literature.

We report a case of hemorrhage in a parasellar meningioma shortly after embolization of the dural cavernous carotid artery branches supplying the tumor. This represents the first report of hemorrhage within a meningioma resulting from embolization with small (50 to 150-microns) polyvinyl alcohol particles, as well as the first reported case of hemorrhage complicating meningioma embolization from internal rather than external carotid artery branch embolization. We also review previously reported cases of postembolization hemorrhage from meningiomas.

A phase 1-2 trial of superselective carboplatin, low-dose infusional 5-fluorouracil and concurrent radiation for high-grade gliomas.

Recent trials have suggested that low-dose infusional 5-FU is more efficacious when given during radiotherapy than is bolus 5-FU. Additionally, intra-arterial cisplatin for brain tumors has been shown to be associated with both high response rates as well as significant toxicity. A dose escalation study was therefore performed using superselective carboplatin, a cisplatin analogue with a favorable CNS toxicity profile in combination with 6 weeks of infusional 5-FU at 225 mg/m2 and concurrent radiotherapy. Eight patients were treated at the starting dose of 200 mg/m2 carboplatin and 11 patients were treated at 300 mg/m2. No toxicity was observed that was attributable to infusional 5-FU. However, two ischemic events related to the superselective delivery of carboplatin were observed, and one patient was noted to have asymptomatic retinal toxicity from the carboplatin. Of 19 patients, 5 had objective responses with 25% or greater reduction in tumor volumes. Continuous infusional 5-FU can be given in combination with partial brain radiotherapy without significant toxicity. Superselective carboplatin delivery is associated with a low incidence of stroke, but no significant retinal toxicity.

Arteriovenous fistula of the scalp after hair transplantation treated by endovascular embolization.

A 27-year-old patient acquired an arteriovenous fistula after punch graft hair transplantation. This lesion was treated by (percutaneous) puncture and injection of a liquid acrylic (N-butyl-2-cyanoacrylate). The fistula was completely obliterated by the endovascular therapy without the need for additional vascular or cosmetic surgery. Endovascular therapy may be helpful as an adjunctive or primary treatment modality for iatrogenic or post-trauma fistulas.

Cranial arteriovenous malformations. The role of embolization and stereotactic surgery.

This article discusses embolization of brain arteriovenous malformations prior to stereotactic surgery. The rationale and goals of treatment are presented. Patient selection, embolization techniques, complications, and postprocedure management are reviewed.

Combined endovascular embolization and surgery in the management of cerebral arteriovenous malformations: experience with 101 cases.

The authors describe their experience with 101 cerebral arteriovenous malformations (AVM's) treated by endovascular embolization followed by surgical removal. Fifty-three patients presented with intracranial hemorrhage and 35 had seizures. Based on the classification of Spetzler and Martin, two AVM's were Grade I, 13 were Grade II, 26 were Grade III, 43 were Grade IV, and 17 were Grade V. Fifty-six AVM's were in the right hemisphere, 28 were in the left hemisphere, 12 were in the corpus callosum, and five involved the cerebellum. In 50 cases, presurgical obliteration of 50% to 75% of the AVM nidus was achieved by embolization, and in 31 cases this percentage increased to between 75% and 90%. In 97 (96%) patients, complete surgical removal of the AVM was obtained. Morbidity resulting from preoperative endovascular embolization was classified as mild in 3.9% of the cases, moderate in 6.9%, and severe in 1.98%. The death rate related to embolization was 0.9%. The immediate postsurgical morbidity was classified as mild in 5.9% of the cases, moderate in 10.8%, and severe in 5.9%. The overall long-term morbidity was mild in 5.9% of the cases, moderate in 6.9%, and severe in 1.98%. Two patients (1.98%) died due to intractable intraoperative hemorrhage and two (1.98%) as a result of postsurgical pulmonary complications.

Angiographic diagnosis and management of head and neck schwannomas.

Schwannomas are tumors derived from nerve sheath cells, which are often located in the head and neck, including the CNS. Although a definitive vascular pattern has been previously characterized for these lesions, preoperative embolization of the more vascular schwannomas has not been described. In a review of eight patients with schwannomas who underwent angiography at our institution since 1987, a characteristic vascular pattern became apparent that helped distinguish these lesions from other lesions of the head and neck. The lesions were moderately vascular with tortuous tumor vessels. Scattered, small puddles of contrast medium seen in the mid-arterial, capillary, and venous phases were believed to be characteristic of these lesions. Multiple feeding vessels were noted in all but one case, but these were only minimally enlarged. No arteriovenous shunting or vascular encasement was identified. Six of eight lesions were embolized with significant devascularization and no morbidity or mortality. In patients with head and neck tumors whose angiographic findings include a pattern of moderate hypervascularity, tortuous tumor vessels, and, in particular, scattered contrast puddles without arteriovenous shunting or vascular encasement, schwannoma should be suspected. Embolization is a useful and safe presurgical adjunct in the treatment of vascular schwannomas.

Neurovascular lesions and endovascular therapy: the role of MR.

Magnetic resonance imaging (MRI) studies were performed on 27 patients with vascular lesions of the central nervous system before and after embolization with either IBCA, polyvinyl alcohol foam particles, Avitene (microfibrillar collagen) or balloons. Thirteen pial brain arteriovenous malformations (AVMs), 3 brain AV fistulas, 2 giant aneurysms, 5 dural AVMs, 1 vertebro-vertebral fistula and 3 meningiomas were studied. The pre-embolization MR demonstrated the nidus and venous drainage of all pial AVMs. MR failed to detect 3 out of 5 dural AVMs using only spin echo sequences. A draining vein alone was seen in the remaining two cases. MR was superior to CT in detecting contiguous parenchymal changes such as atrophy, reversible ischemia, and mass effect in the pre-embolization studies. Following embolization, MR demonstrated partial or complete obliteration of the vascular nidus in all 13 pial AVMs. The embolized area was seen as an area of increased signal consistent with thrombus where previously there had been signal void. Ischemic or edematous changes in the brain parenchyma following embolization were seen on MR more easily than on CT scans. MR was accurate in the assessment of aneurysm patency, degree of thrombosis and balloon position in both giant aneurysms, and AV fistulae. These MR findings had an impact on patient management. MR will be an increasingly useful tool in the diagnosis and management of a number of neurovascular diseases requiring endovascular intervention.

Dextran microsphere embolization: experimental and clinical experience with radiologic-pathologic correlation. Work in progress.

The radiologic and pathologic effects of canine renal embolization with dextran microspheres of two size ranges (40-150 micron and 100-300 micron) were studied 30 minutes and 1, 2, 4, and 6 weeks after embolization. Dramatic occlusions occurred with very small quantities of these particles, which reached more distally and were suspended and embolized more easily than other solid embolic agents. Because of these qualities, however, they should be used with more caution. They can be injected through 2-F catheters, calibrated-leak balloons, and open-ended guide wires. Embolization with dextran microspheres was also used for epistaxis, meningioma, dural arteriovenous malformation, renal tumors, bone metastasis, multiple myeloma, or peripheral angioma in ten patients. The technique was safe and effective, but special attention should be directed to proper dilution and gentle embolization with careful monitoring to avoid excessive embolization or reflux.

CT demonstration of hemiatrophy and fatty replacement of the tongue.

We report a patient in whom computed tomography was used to demonstrate denervation, hemiatrophy and fatty replacement of the tongue, secondary to lower motor neuron involvement of the hypoglossal nerve by a meningioma. This unusual finding has only been described once before.