Faculty Bibliography

Dural arteriovenous fistulas (DAVFs) are rare pathological entities presenting with a diverse clinical course, ranging from benign to life-threatening. Digital subtraction angiography remains the gold standard in the diagnosis of clinically suspected DAVFs. This article reviews the ethiopathogenesis, natural history, classification systems, clinical and angiographic features, and the current treatment strategies for these complex lesions. The management of DAVFs may include conservative treatment, endovascular intervention, microsurgery, and stereotactic radiosurgery. A multidisciplinary approach involving a neurosurgeon, interventional neuroradiologist, and neurologist is required before considering any type of treatment modality. The indication for the best therapeutic alternative must be individualized for each patient.

OBJECTIVE: We introduce a technique that uses intraoperative flat-panel detector computed tomography (FD-CT) and three-dimensional rotational angiography (3D-RA) acquired in the hybrid operative suite to provide full neuronavigation capabilities during cerebrovascular surgery without the use of preoperative imaging studies. METHODS: An Artis Zeego FD system (Siemens AG, Forchheim, Germany), mounted on a robotic C-arm was used during the clipping of an aneurysm to acquire intraoperative FD-CT and 3D-RA images. These images were then fused via the use of BrainLab iPlan 3.0 software and sent to a Vector Vision Sky neuronavigation system (NNS; BrainLAB, Heimstetten, Germany) to provide intraoperative image guidance. RESULTS: The use of intraoperative FD-CT and 3D-RA with a NNS allowed for accurate visualization of the vascular anatomy and localization of pathology. In a case of a patient harboring two aneurysms, one that was surgically clipped and a second that was treated endovascularly, the 3D-RA clearly showed neck remnants at both aneurysms. Use of the NNS assisted in further clip placement for obliteration of these neck remnants. CONCLUSIONS: Hybrid operating suites equipped with FD-CT, 3D-RA, and NNS capabilities can be used to provide intraoperative 3D image guidance during cerebrovascular surgery with excellent accuracy and without the need for preoperative angiography. Furthermore, this technique required less than 15 minutes for image acquisition and utilizes digitally subtracted angiographic images that are superior to conventional CT or MRI for the imaging of cerebrovascular pathology.

BACKGROUND AND PURPOSE: SIACI of bevacizumab has emerged as a promising novel therapy in the treatment of recurrent GB. This study assessed the potential of (1)H-MRS as an adjunctive technique in detecting metabolic changes reflective of antiproliferative effects of targeted infusion of bevacizumab in the treatment of GB. MATERIALS AND METHODS: Eighteen patients enrolled in a phase I/II study of SIACI of bevacizumab for treatment of recurrent GB were included. Concurrent MR imaging and (1)H-MRS scans were performed before and after treatment. Five distinct morphologic ROIs were evaluated for structural and metabolic changes on MR imaging and (1)H-MRS, which included enhancing, nonenhancing T2 hyperintense signal abnormality, and multiple control regions. Pre- and post-SIACI of bevacizumab peak areas for NAA, tCho, tCr, as well as tCho/tCr and tCho/NAA ratios, were derived for all 5 ROIs and compared using the Wilcoxon signed-rank test. RESULTS: A significant median decrease of 25.99% (range -55.76 to 123.94; P = .006) in tCho/NAA was found post-SIACI of bevacizumab relative to pretreatment values in regions of enhancing disease. A trend-level significant median decrease of 6.45% (range -23.71 to 37.67; P = .06) was noted in tCho/NAA posttreatment in regions of nonenhancing T2-hyperintense signal abnormality. CONCLUSIONS: The results of this (1)H-MRS analysis suggest that GB treatment with SIACI of bevacizumab may be associated with a direct antiproliferative effect, as demonstrated by significant reductions of tCho/NAA after the intervention.

BACKGROUND AND PURPOSE: Intraprocedural aneurysmal rupture is a feared complication of coil embolization of intracranial aneurysms and is associated with high rates of morbidity and mortality. We report the incidence, endovascular management, and clinical outcome of patients with IAR, with emphasis on the role of the balloon-assisted technique. MATERIALS AND METHODS: We conducted a retrospective analysis of all intracranial aneurysms treated by coil embolization between September 2001 and June 2011. All patients with IAR were studied. Comparison of immediate clinical outcomes was performed by using univariate analysis (Fisher exact test). RESULTS: Of 652 intracranial aneurysms treated with coil embolization, an IAR occurred in 22 (3.4%). Rupture occurred during placement of coils in 18 cases, microcatheters in 2 cases, and a guidewire in 1 case, and during induction of anesthesia in 1 case. Before treatment, 15 of 22 (68%) patients were in good clinical condition (WFNS grade I). There were fewer patients with worsening of the WFNS grade following an IAR when the balloon-assisted technique was used (7.7%) compared with when it was not (55.5%) (P = .023). Death occurred in 2 (9.1%) patients. CONCLUSIONS: IAR is a potentially serious complication of coil embolization. If IAR occurs, balloon-assistance is helpful in obtaining rapid hemostasis resulting in better short-term outcomes.

Neurofibromatosis type 2 (NF2) is an autosomal dominant syndrome with a prevalence of approximately 1 in 30,000. NF 2 is characterized by bilateral vestibular schwannomas, as well as meningiomas, ependymomas and gliomas. Currently, surgical resection and radiotherapy represent the mainstay of treatment, although new studies suggest a role for certain chemotherapeutic agents. Intravenous administration of Bevacizumab (Avastin, Genetech Pharmaceuticals) has been shown to be active in the treatment of vestibular schwannomas. The IV route of administration, however, carries a risk of known systemic side-effects such as bowel perforation, wound dehiscence and pulmonary embolism. In addition, the percentage of drug that reaches the tumor site may be restricted by the blood tumor barrier. This report describes the super-selective intra-arterial infusion of Bevacizumab following blood brain barrier disruption for the treatment of vestibular schwannomas in three patients with Neurofibromatosis type 2. It represents the first time such a technique has been performed for this disease. Additionally, this method of drug delivery may have important implications in the treatment of patients with vestibular schwannomas associated with Neurofibromatosis type 2.

BACKGROUND: : Neuroform stent-assisted coil embolization facilitates the endovascular treatment of wide-necked intracranial aneurysms. However, the safety and efficacy of its long-term use have not been fully elucidated. OBJECTIVE: : To retrospectively examine the long-term results of Neuroform stent usage in conjunction with coil embolization in wide-necked intracranial aneurysms. METHODS: : Between November 2002 and December 2010, 79 patients harboring wide-necked intracranial aneurysms were treated with use of the Neuroform stent. The stenting procedure failed in 2 patients. Therefore, 77 patients harboring 79 intracranial aneurysms were included for analysis. Patient and aneurysm characteristics, progression of aneurysm occlusion, and occurrence of complications were analyzed. Follow-up imaging included digital subtraction angiography (DSA) or magnetic resonance angiography (MRA). Kaplan-Meier analysis, as well as univariate analysis were performed to determine the progression of aneurysm occlusion and to examine the predictive factors for complete aneurysm occlusion, respectively. RESULTS: : Overall, complete aneurysm occlusion was observed in 42.4% of the cases immediately after treatment and progressed to 96.5% at 7-year follow-up. The mean angiographic follow-up time was 25.8 months (range, 0-84 months). Eleven aneurysms (14%) were re-treated. Sixty-eight patients (88.3%) had favorable clinical outcome with a modified Rankin Scale (mRS)