Andrew A. Fanous

Correlation between cerebral blood volume values and outcomes in endovascular therapy for acute ischemic stroke

Background Neurointerventionalists do not agree about the optimal imaging protocol when evaluating patients with acute stroke for potential endovascular revascularization. Preintervention cerebrovascular blood volume (CBV) has been shown to predict outcomes in patients undergoing intra-arterial stroke therapies. Objective To determine whether CBV can predict hemorrhagic transformation and clinical outcomes in patients selected for endovascular therapy for acute ischemic middle cerebral artery (MCA) stroke using a CT perfusion (CTP)-based imaging protocol. Methods We retrospectively reviewed cases of acute ischemic stroke due to MCA M1 segment occlusion and correlated favorable clinical outcomes (modified Rankin scale (mRS) ≤2) and radiographic outcomes with preintervention CBV values. All patients underwent whole-brain (320-detector-row) CTP imaging, and absolute CBV values of the affected and contralateral MCA territories were obtained separately for the cortical and basal ganglia regions. Results Relative CBV (rCBV) of the MCA cortical regions was significantly lower in patients with poor clinical outcomes than in those with favorable clinical outcomes (0.87±0.21 vs 1.02±0.09, p=0.0003), and a negative correlation was found between rCBV values and mRS score severity. rCBV of the basal ganglia region was significantly lower in patients with hemorrhagic infarction (p=0.004) and parenchymal hematoma (p=0.04) than in those without hemorrhagic transformation. Conclusions We found that cortical CBV loss is predictive of poor clinical outcomes, whereas basal ganglia CBV loss is predictive of hemorrhagic transformation but without translation into poor clinical outcomes. Our study findings support published results of baseline preintervention CBV as a predictor of outcomes in patients undergoing intra-arterial stroke therapies.

High-Risk Factors in Symptomatic Patients Undergoing Carotid Artery Stenting With Distal Protection: Buffalo Risk Assessment Scale (BRASS).

BACKGROUND Demographics and vascular anatomy may play an important role in predicting periprocedural complications in symptomatic patients undergoing carotid artery stenting (CAS). OBJECTIVE To predict factors associated with increased risk of complications in symptomatic patients undergoing CAS and to devise a CAS scoring system that predicts such complications in this patient population. METHODS A retrospective study was conducted that included patients who underwent CAS for symptomatic carotid stenosis during a 3-year period. Demographics and anatomic characteristics were subsequently correlated with 30-day outcome measures. RESULTS A total of 221 patients were included in the study. The cumulative rate of periprocedural complications was 7.2%, including stroke (3.2%), myocardial infarction (3.2%), and death (1.4%). Renal disease increased the risk of all complications. National Institutes of Health Stroke Scale score ≥10 at presentation, difficult femoral access, and diseased calcified aortic arch increased the risk of stroke and all complications. Type III aortic arch correlated with increased risk of stroke. Pseudo-occlusion and concentric calcification of the carotid artery increased the risk of myocardial infarction, death, and all complications. Carotid tortuosity and anatomy hostile to the deployment of distal protection devices increased the risk of stroke, myocardial infarction, death, and all complications. CONCLUSION Our results suggest that CAS should be avoided in patients with multiple anatomic risk factors. High presenting National Institutes of Health Stroke Scale score and renal disease also increase the complication risk. The CAS scoring system devised here is simple, reproducible, and clinically valuable in predicting complications risk in symptomatic patients undergoing CAS.

A Nonenhancing World Health Organization Grade II Intramedullary Spinal Ependymoma in the Conus: Case Illustration and Review of Imaging Characteristics

Spinal ependymomas comprise ~60% of all intramedullary tumors in adults. Ependymomas demonstrate distinct imaging features, such as central location within the spinal cord, symmetrical expansion, intra- and extratumoral cysts, hemosiderin caps, and strong enhancement on contrast-injected, T1-weighted magnetic resonance (MR) imaging. In adults, most ependymomas are myxopapillary, and in children, most are nonmyxopapillary. In general, nonmyxopapillary or classic ependymomas are hyperintense on T2- and hypointense on T1-weighted MR imaging, but whereas the signal intensity on T1 and T2 is variable, homogeneous contrast enhancement is usually a characteristic finding. Here, the authors provide an overview on spinal ependymomas with an emphasis on imaging characteristics and morphological background and present the case of a World Health Organization grade II ependymoma in the conus that did not enhance. Interestingly, the tumor contained a large hemorrhagic cyst. Just as hemorrhagic metastatic tumors may not enhance, a hemorrhagic ependymoma may likewise not enhance after administration of contrast agent. Thus, the differential diagnosis of a nonenhancing intramedullary lesion in the conus should include ependymoma, particularly if there is concomitant hemorrhage.

The Impact of Preoperative Angiographic Identification of the Artery of Adamkiewicz on Surgical Decision Making in Patients Undergoing Thoracolumbar Corpectomy.

Study Design. Retrospective study. Objective. To investigate the impact of spinal angiography on selection of surgical side in patients undergoing thoracolumbar corpectomy. Summary of Background Data. The artery of Adamkiewicz provides the major blood supply to the thoracolumbar spinal cord. Its location makes it vulnerable to injury during surgical procedures. Preoperative diagnostic spinal angiography is often used to determine the level and lateralization of the artery. Methods. Data were gathered regarding level and laterality of the Adamkiewicz artery in 34 patients who underwent lateral extracavitary approaches to the thoracolumbar spine, preceded by diagnostic spinal angiography for localization of that artery. Two experienced spine surgeons were retrospectively polled regarding ideal side of approach for each case. This was compared with the actual side that was selected after angiographic localization. Results. The artery was successfully identified in 71% of patients. The artery was most commonly located on the left side (83%) between T9 and L1 (83%). Diagnostic angiography seemed to have influenced surgical decision making in 54% of cases. In 21% of patients, there was no need to alter the side of approach. In the remaining 25%, the surgical plan was not altered on the basis of angiographic data, presumably due to anatomic limitations. No angiography- or surgery-related complications occurred in any of the patients. Conclusion. Preoperative spinal angiography seems to impact surgical decision making with regard to alteration of the side of approach in patients undergoing thoracolumbar corpectomy via lateral extracavitary approaches. Level of Evidence: 4

Frameless and Maskless Stereotactic Navigation with a Skull-Mounted Tracker

OBJECTIVE In this series, we present 3 cases that show the use of a skull-mounted tracker for image-guided navigation for anterior skull base surgery and ventricular catheter placement procedures. This system obviates fiducials or face masks during the surgical procedure itself and allows for the performance of facial incisions using the Weber-Ferguson approach. METHODS Our series presents the use of a novel intraoperative navigational system that uses a skull-mounted tracker to navigated anterior skull base surgery. RESULTS We present 3 cases using this new system: 1 anterior skull base tumor removal that was operated on without a facemask for navigation and 2 ventricular catheter placement procedures. CONCLUSIONS Intraoperative image-guided navigation has revolutionized neurosurgery. It undoubtedly increases the surgeons confidence and the perception of safety. Although fiducials and facial masks are the most widely used tools for intraoperative navigation, their use is associated with certain complications. This technique permits free movement of the head during surgery, which in turn facilitates the exposure of head and neck lesions and expedites the approach to ventricular catheter placement. Our case series shows the precision and ease of our technique, which is less time consuming and less cumbersome than the traditional frame-based stereotaxy. In addition, the skull-mounted tracker system allows improved anatomic localization and shorter operating time and avoids the complications associated with the use of rigid fixating head frames.