Faculty Bibliography

StarVIBE is a 3D gradient-echo sequence with a radial, stack-of-stars acquisition having spatial resolution and tissue contrast. With newer sequences, it is important to be familiar with sequence tissue contrasts and appearance of anatomical variants. We evaluated 450 patients utilizing this sequence; 35 patients demonstrated fluffy "cotton wool" enhancement at the internal auditory canal fundus without clear pathology. We favor this represents anatomic neurovascular enhancement that StarVIBE is sensitive to and is a touch-me-not finding.

Background Vasospasm is a treatable cause of deterioration following aneurysmal subarachnoid hemorrhage. Cerebral computed tomography perfusion mean transit times have been proposed as a predictor of vasospasm but suffer from well-known technical limitations. We evaluated fully automated, thresholded time-to-maxima of the tissue residue function (T

OBJECTIVE:Perfusion imaging identifies anterior circulation stroke patients who respond favorably to endovascular thrombectomy (ET), but its role in basilar occlusion (BAO) is unknown. We hypothesized that BAO patients with limited regions of severe hypoperfusion (Time-to-maximum [Tmax] delay >10 seconds) would have a favorable response to ET compared to patients with more extensive regions involved. METHODS:We performed a multicenter retrospective cohort study of BAO patients with perfusion imaging prior to ET. We pre-specified a Critical Area Perfusion Score (CAPS; 0-6 points), which quantified severe hypoperfusion (Tmax >10s) in cerebellum (1 point/hemisphere), pons (2 points), midbrain and/or thalamus (2 points). Patients were dichotomized into favorable (CAPS≤3) and unfavorable (CAPS>3) groups. The primary outcome was a favorable functional outcome 90-days after ET (modified Rankin Scale [mRS] 0-3). RESULTS:103 patients were included. CAPS≤3 patients (87%) had a lower median NIHSS (12.5 [IQR 7-22]) compared to CAPS>3 patients (13%) (23 [IQR 19-36]; p=0.01). Reperfusion was achieved in 84% of all patients with no difference between CAPS groups (p=0.42). 64% of reperfused CAPS≤3 patients had a favorable outcome compared to 8% of non-reperfused CAPS≤3 patients (OR=21.0 [95% CI 2.6-170]; p<0.001). No CAPS>3 patients had a favorable outcome, regardless of reperfusion. In a multivariable regression analysis, CAPS≤3 was a robust independent predictor of favorable outcome after adjustment for reperfusion, age, and pre-ET NIHSS (OR 39.25 [95% CI 1.34->999)]; p=0.04). INTERPRETATION/CONCLUSIONS:BAO patients with limited regions of severe hypoperfusion had a favorable response to reperfusion following ET. However, patients with more extensive regions of hypoperfusion in critical brain regions did not benefit from endovascular reperfusion. This article is protected by copyright. All rights reserved.

The purpose of this study was to assess spatially remote effects of hemodynamic impairment on functional network topology contralateral to unilateral anterior circulation steno-occlusive disease (SOD) using resting-state blood oxygen level-dependent (BOLD) imaging, and to investigate the relationships between network connectivity and cerebrovascular reactivity (CVR), a measure of hemodynamic stress. Twenty patients with unilateral, chronic anterior circulation SOD and 20 age-matched healthy controls underwent resting-state BOLD imaging. Five-minute standardized baseline BOLD acquisition was followed by acetazolamide infusion to measure CVR. The BOLD baseline was used to analyze network connectivity contralateral to the diseased hemispheres of SOD patients. Compared to healthy controls, reduced network degree (z-score = -1.158 ± 1.217, P < 0.001, false discovery rate (FDR) corrected), local efficiency (z-score = -1.213 ± 1.120, P < 0.001, FDR corrected), global efficiency (z-score = -1.346 ± 1.119, P < 0.001, FDR corrected), and enhanced modularity (z-score = 1.000 ± 1.205, P = 0.002, FDR corrected) were observed in the contralateral, normal hemispheres of SOD patients. Network degree (P = 0.089, FDR corrected; P = 0.027, uncorrected) and nodal efficiency (P = 0.089, FDR corrected; P = 0.045, uncorrected) showed a trend toward a positive association with CVR. The results indicate remote abnormalities in functional connectivity contralateral to the diseased hemispheres in patients with unilateral SOD, despite the absence of macrovascular disease or demonstrable hemodynamic impairment. The clinical impact of remote functional disruptions requires dedicated investigation but may portend far reaching consequence for even putatively unilateral cerebrovascular disease.

Stroke poses an immense public health burden and remains among the primary causes of death and disability worldwide. Emergent therapy is often precluded by late or indeterminate times of onset before initial clinical presentation. Rapid, mobile, safe and low-cost stroke detection technology remains a deeply unmet clinical need. Past studies have explored the use of microwave and other small form-factor strategies for rapid stroke detection; however, widespread clinical adoption remains unrealized. Here, we investigated the use of microwave scattering perturbations from ultra wide-band antenna arrays to learn dielectric signatures of disease. Two deep neural networks (DNNs) were used for: (1) stroke detection ("classification network"), and (2) characterization of the hemorrhage location and size ("discrimination network"). Dielectric signatures were learned on a simulated cohort of 666 hemorrhagic stroke and control subjects using 2D stochastic head models. The classification network yielded a stratified K-fold stroke detection accuracy > 94% with an AUC of 0.996, while the discrimination network resulted in a mean squared error of < 0.004 cm and < 0.02 cm, for the stroke localization and size estimation, respectively. We report a novel approach to intelligent diagnostics using microwave wide-band scattering information thus circumventing conventional image-formation.

BACKGROUND AND PURPOSE/OBJECTIVE:delays in patients with large vessel occlusion evaluated between 6 and 16 hours from last known normal. METHODS:6 or 10 s volume-baseline core volume). We stratified the cohort into 4 categories based on treatment modality and Thrombolysis in Cerebral Infarction (TICI score; untreated, TICI 0-2a, TICI 2b, and TICI3) and calculated penumbral consumption rates in each category. RESULTS:=0.92). CONCLUSIONS:>6-s mismatch volume may remain viable in untreated patients at 24 hours.