Faculty Bibliography

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

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:High-resolution vessel wall MRI (VWI) is increasingly used to characterize intramural disorders of the intracranial vasculature unseen by conventional arteriography. OBJECTIVE:To evaluate the use of VWI for surveillance of flow diverter (FD) treated aneurysms. MATERIALS AND METHODS/METHODS:Retrospective study of 28 aneurysms (in 21 patients) treated with a FD (mean 57 years; 14 female). All examinations included VWI and a contemporaneously obtained digital subtraction angiogram. Multiplanar pre- and post-gadolinium 3D, variable flip-angle T1 black-blood VWI was obtained using delay alternating nutation for tailored excitation (DANTE) at 3T. 3D time-of-flight MR angiography (MRA) was also carried out. Images were assessed for in-stent stenosis, aneurysm occlusion, presence and pattern/distribution of aneurysmal or parent vessel gadolinium enhancement. RESULTS:The VWI-MRI was performed on average at 361±259 days after the intervention. Follow-up DSA was performed at 338±254 days postintervention. Good or excellent black-blood angiographic quality was recorded in 22/28 (79%) pre-contrast and 21/28 (75%) post-contrast VWI, with no cases excluded for image quality. Aneurysm enhancement was noted in 24/28 (85.7%) aneurysms, including in 79% of angiographically occluded aneurysms and 100% of angiographically non-occluded aneurysms. Enhancement of the stented parent-vessel wall occurred significantly more often when aneurysm enhancement was present (92% vs 33%, p=0.049). CONCLUSION/CONCLUSIONS:Advanced VWI produces excellent depiction of FD-treated aneurysms, with robust evaluation of the parent vessel and aneurysm wall to an extent not achievable with conventional MRI/MRA. Gadolinium enhancement may, however, continue even after enduring catheter angiographic occlusion, confounding interpretation, and requiring cognizance of this potentially prolonged effect in such patients.

BACKGROUND:The association between race and ethnicity and microvascular disease in patients with intracerebral hemorrhage (ICH) is unclear. We hypothesized that social determinants of health (SDOHs) mediate the relationship between race and ethnicity and severity of white matter hyperintensities (WMHs) and microbleeds in patients with ICH. METHODS:We performed a retrospective observational cohort study of patients with ICH at two tertiary care hospitals between 2013 and 2020 who underwent magnetic resonance imaging of the brain. Magnetic resonance imaging scans were evaluated for the presence of microbleeds and WMH severity (defined by the Fazekas scale; moderate to severe WMH defined as Fazekas scores 3-6). We assessed for associations between sex, race and ethnicity, employment status, median household income, education level, insurance status, and imaging biomarkers of microvascular disease. A mediation analysis was used to investigate the influence of SDOHs on the associations between race and imaging features. We assessed the relationship of all variables with discharge outcomes. RESULTS:We identified 233 patients (mean age 62 [SD 16]; 48% female) with ICH. Of these, 19% were Black non-Hispanic, 32% had a high school education or less, 21% required an interpreter, 11% were unemployed, and 6% were uninsured. Moderate to severe WMH, identified in 114 (50%) patients, was associated with age, Black non-Hispanic race and ethnicity, highest level of education, insurance status, and history of hypertension, hyperlipidemia, or diabetes (p < 0.05). In the mediation analysis, the proportion of the association between Black non-Hispanic race and ethnicity and the Fazekas score that was mediated by highest level of education was 65%. Microbleeds, present in 130 (57%) patients, was associated with age, highest level of education, and history of diabetes or hypertension (p < 0.05). Age, highest level of education, insurance status, and employment status were associated with discharge modified Rankin Scale scores of 3-6, but race and ethnicity was not. CONCLUSIONS:The association between Black non-Hispanic race and ethnicity and moderate to severe WMH lost significance after we adjusted for highest level of education, suggesting that SDOHs may mediate the association between race and ethnicity and microvascular disease.

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.

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.

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.