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BACKGROUND AND PURPOSE: The introduction of flow diverters (FDs) has expanded the possibilities for reconstructive treatment of difficult intracranial aneurysms. Concern remains as to the long-term patency of the perforating arteries and side branches covered during stent placement. Our purpose was to evaluate the performance of and early effect on covered branches after implantation of the Silk FD in the treatment of basilar artery aneurysms. METHODS: Twelve patients with an aneurysm of the basilar artery that was treated by implantation of the Silk FD were included in our retrospective study. Both unruptured and previously ruptured, formerly untreated, and recurrent aneurysms were treated. During follow-up, patients were monitored for clinical evolution, patency of the covered vessels, and aneurysmal obliteration. RESULTS: Of the 2 ruptured aneurysms, 1 was initially treated by FD implantation. The FD covered the basilar bifurcation and the origin of a P1 segment of the posterior cerebral artery in 9 cases, the origin of the superior cerebellar artery in 9, and of the anterior inferior cerebellar artery in 3. There was 1 acute basilar artery occlusion a few hours after FD implantation. During a mean follow-up of 16 weeks, 3 patients experienced a symptomatic neurologic event. CONCLUSIONS: Implantation of the Silk FD in the basilar artery was feasible and well tolerated in most cases to date. However, late ischemic events affecting perforating arteries may occur after FD implantation, suggesting that the indication should be restricted to otherwise untreatable aneurysms in this location.

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INTRODUCTION: Cerebral embolism is the principal cause of cerebral infarction. Recently, mechanical embolectomy has been proposed as an effective method. We performed a preclinical evaluation of a new mechanical clot-retrieving wire. METHODS: This clot-retrieving wire consisted of three nitinol loops at the tip of a microguidewire. These three loops could be collapsed into a 0.018-inch wire compatible microcatheter. Each loop was 8 mm long and 3.5 mm wide. For simulation, polyvinyl alcohol (PVA) vascular anatomical models of the human carotid (eight models) and vertebrobasilar (three models) circulation were constructed. A pulsatile flow circulation system was used. Embolic clots were produced using pig blood plasma. The microcatheter and the microguidewire were advanced beyond the clot. The wire was then exchanged for the retrieving wire. The microcatheter was then pulled slightly back to open the loops. The clot was then caught by withdrawal of the system. Once caught, the clot was retrieved to the guiding catheter tip. We investigated the following points: ease of device deployment, clot capture ability, clot removal against blood flow and removal of the clot out of the introducer system. RESULTS: A total of 104 procedures were performed in 11 PVA models and evaluated. The drop rate was 19%. We succeeded in partial and total recanalization in 51.0% of the procedures (53/104) within 30 minutes. CONCLUSION: This new clot-retrieving wire could be useful for mechanical clot extraction in stroke.

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Intracranial stenting is increasingly being used to treat intracranial aneurysms and stenoses. We wanted to assess the utility of magnetic resonance angiography (MRA) in the follow-up of patients treated with various types of intracranial stents and to assess the utility of performing gadolinium-enhanced MRA. A total of 19 patients having undergone intracranial stenting for aneurysms were imaged by MRI at 1.5T. A total of 20 stents were placed in 19 patients. In addition to conventional T2- and diffusion-weighted MRI, 3D time-of-flight MRA was performed before and after contrast administration. In the case of metallic INX stents (N = 7), there was a signal drop at the level of the vessel. which did not allow to evaluating the parent vessel, whereas this was visible in Nitinol stents (N = 8). Additionally a stent with a wire had a small artifact (N = 3). Contrast administration also improved vessel lumen visualization. In the case of Nitinol stents, MRA can be used to reliably demonstrate the vessel lumen after intracranial stenting. The use of postcontrast 3D time-of-flight imaging helps improve the intraluminal definition.

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OBJECTIVE: MDCT angiography allows fast imaging of the cerebral vessels, and its potential as a noninvasive technique to detect vascular abnormalities on the basis of morphologic changes is well established. We analyzed vascular enhancement patterns of cerebral venous structures on MDCT angiography, which enabled us to diagnose dural arteriovenous fistula. CONCLUSION: MDCT angiography performed during an early arterial phase showed asymmetrically higher contrast intensity in the transverse or sigmoid sinus, or both, in five patients. In all patients, digital subtraction angiography confirmed the presence of a dural arteriovenous fistula on the side on which the higher contrast intensity appeared. Radiologists should actively look for this sign in the imaging workup of patients presenting with nonspecific symptoms that might be related to a dural arteriovenous fistula.

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For the treatment of lytic disease involving the pedicles of vertebrae in patients with metastatic disease, the authors performed percutaneous vertebroplasty by using an access route via the lysed pedicle. Fifty-one pedicles were treated in 32 consecutive patients. In all cases, a radiologically satisfactory filling of both the affected pedicle and the vertebral body was achieved. Clinically effective pain relief was obtained in 24 (75%) of 32 patients, and no clinical complications were observed.

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STUDY DESIGN: During vertebroplasty (VP), polymethylmethacrylate (PMMA) may leak into the posterior epidural venus plexus, provoking symptoms ranging from radicular pain to medullar compression. OBJECTIVES: To propose and test the feasibility of a procedure (cooling system) to prevent radicular irritation caused by foraminal PMMA leakage. SUMMARY OF BACKGROUND DATA: Foraminal leak of PMMA, as observed during VP, may lead to radiculalgia. Several mechanisms of nerve root irritation have been proposed. Considering heat or local chemical irritation has led us to treat immediately by local periradicular irrigation with a cooling liquid. METHODS: Four consecutive patients with observed foraminal leakage were treated by local fluid injection. Immediately after observation of a foraminal leak, a 20-gauge Chiba needle was positioned to reach the foramen. Ten cubic centimeters of lidocaine (0.2%) was followed by 100-200 cc of pressurized saline perfusion within 10-20 minutes (cooling system). RESULTS: In all patients with foraminal leakage, no radicular pain existed after application of the cooling system. No complications were observed with its use. CONCLUSION: In presence of a foraminal leakage, the immediate application of a cooling irrigation may protect the root from injury, which is explained by the hypothesis that the main mechanism of injury may be more related to heat or chemical irritation of the nerve than compression.

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