Faculty Bibliography

BACKGROUND:Age and infarct volume are among the most powerful predictors of outcome after large vessel occlusion acute strokes (LVOS). OBJECTIVE:To study the impact of age-adjusted final infarct volume (FIV) on functional outcomes. METHODS:Review of a prospectively collected thrombectomy database at a tertiary care center between September 2010 and February 2018. Consecutive patients with anterior circulation LVOS who achieved full reperfusion (modified Thrombolysis in Cerebral Infarction 3) were categorized into four age groups: (G1) <60 years, (G2) 60-69, (G3) 70-79, (G4) ≥80 years. The Youden Index was used to identify the optimal FIV cut-off point for good outcome (modified Rankin Scale score 0-2) discrimination in each group and the overall population. The predictive ability of these specific thresholds was evaluated using binary logistic regressions and compared with the non-age-adjusted cut-off point. RESULTS:516 patients were analyzed (G1: n=171, G2: n=130, G3: n=103, G4: n=112). Patients with poor outcome had a larger FIV in each group (p<0.01 for all). The target FIV cut-off point decreased with increased age: G1: 45.7 mL (sensitivity 56%, specificity 80%); G2: 30.4 mL (sensitivity 63%, specificity 75%); G3: 20.2 mL (sensitivity 76%, specificity 65%); G4: 16.9 mL (sensitivity 68%, specificity 70%). The non-age-adjusted cut-off point was 19.2 mL (sensitivity 70%, specificity 59%).In multivariate analysis, adjusting for confounders including age and FIV, achieving a FIV less than the age-adjusted threshold was an independent predictor of good outcome (aOR=2.72, 95% CI 1.41 to 5.24, p<0.001). In contrast, a similar model including the non-age-adjusted target cut-off point failed to reveal an association with good outcome (aOR=1.72, 95% CI 0.93 to 3.19, p<0.085). Furthermore, the latter model had a weaker outcome predictive ability as assessed by the Akaike information criterion (409 vs 403). CONCLUSIONS:Age-adjusted infarct volume represents a strong outcome discriminator beyond age and infarct volume in isolation and might help to refine patient selection and improve outcome prognostication in stroke thrombectomy.

OBJECTIVES/OBJECTIVE:To assess whether MR fingerprinting (MRF)-based relaxation properties exhibit cross-sectional and prospective correlations with patient outcome and compare the results with those from DTI. METHODS:from MRF were compared in 12 gray and white matter regions with Mann-Whitney tests. Bivariate associations between MR measures and outcome were assessed using the Spearman correlation and logistic regression. RESULTS:, accounted for five of the six MR measures with the highest utility for identification of non-recovered patients at timepoint 2 (AUC > 0.80). CONCLUSION/CONCLUSIONS:, FA, and ADC for predicting 3-month outcome after mTBI. KEY POINTS/CONCLUSIONS:, and FA.

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.