Contralateral Hemispheric Cerebral Blood Flow Measured With Arterial Spin Labeling Can Predict Outcome in Acute Stroke.

Background and Purpose- Imaging is frequently used to select acute stroke patients for intra-arterial therapy. Quantitative cerebral blood flow can be measured noninvasively with arterial spin labeling magnetic resonance imaging. Cerebral blood flow levels in the contralateral (unaffected) hemisphere may affect capacity for collateral flow and patient outcome. The goal of this study was to determine whether higher contralateral cerebral blood flow (cCBF) in acute stroke identifies patients with better 90-day functional outcome. Methods- Patients were part of the prospective, multicenter iCAS study (Imaging Collaterals in Acute Stroke) between 2013 and 2017. Consecutive patients were enrolled after being diagnosed with anterior circulation acute ischemic stroke. Inclusion criteria were ischemic anterior circulation stroke, baseline National Institutes of Health Stroke Scale score ≥1, prestroke modified Rankin Scale score ≤2, onset-to-imaging time <24 hours, with imaging including diffusion-weighted imaging and arterial spin labeling. Patients were dichotomized into high and low cCBF groups based on median cCBF. Outcomes were assessed by day-1 and day-5 National Institutes of Health Stroke Scale; and day-30 and day-90 modified Rankin Scale. Multivariable logistic regression was used to test whether cCBF predicted good neurological outcome (modified Rankin Scale score, 0-2) at 90 days. Results- Seventy-seven patients (41 women) met the inclusion criteria with median (interquartile range) age of 66 (55-76) yrs, onset-to-imaging time of 4.8 (3.6-7.7) hours, and baseline National Institutes of Health Stroke Scale score of 13 (9-20). Median cCBF was 38.9 (31.2-44.5) mL per 100 g/min. Higher cCBF predicted good outcome at day 90 (odds ratio, 4.6 [95% CI, 1.4-14.7]; P=0.01), after controlling for baseline National Institutes of Health Stroke Scale, diffusion-weighted imaging lesion volume, and intra-arterial therapy. Conclusions- Higher quantitative cCBF at baseline is a significant predictor of good neurological outcome at day 90. cCBF levels may inform decisions regarding stroke triage, treatment of acute stroke, and general outcome prognosis. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT02225730

Anatomical predictors of gastrostomy tube placement after large vessel occlusion ischemic stroke

Dysphagia is a common neurologic deficit following ischemic stroke. As a result, patients often require percutaneous endoscopic gastrostomy (PEG) tube placement for safe maintenance of sufficient caloric intake. Right hemispheric strokes have previously been associated with post-stroke dysphagia. We examined whether topographic location of post-large vessel occlusion (LVO) stroke MR diffusion-weighted imaging (DWI) lesions associated with the need for placement of PEG tube. A retrospective registry of 898 patients evaluated for acute treatment of suspected LVO stroke was used. Sixty-five patients underwent post-stroke PEG placement, and 65 additional patients were selected as propensity matches based on age, baseline NIH Stroke Scale score, and recanalization status. Binary masks of 24–72-h post-stroke DWI lesions were co-registered to standard template space. Voxel-based lesion symptom mapping (V2.55), rewritten to perform logistic regression at each voxel, was used to generate statistical maps of lesion contribution to PEG placement. Results: Uncorrected t-statistic maps demonstrated voxels in the right frontal, parietal, and temporal regions were associated with post-stroke PEG placement. Upon controlling for age and/or recanalization status, lesions in the right parietal lobe were associated with need for PEG. After controlling for lesion volume, this association weakened. After controlling for all variables, there were no topographical regions associated with PEG placement. There does not appear to be any topographic region on post-stroke diffusion MRI that is significantly associated with need for PEG placement in patients with LVO stroke after controlling for age, recanalization status, and lesion size

StrokeCog-15 Is an Efficient Neuropsychological Battery to Screen for Cognitive Impairment in Chronic Stroke

BACKGROUND:Poststroke cognitive impairment can significantly impact functional outcomes and quality of life. While comprehensive neuropsychological evaluations are valuable in characterizing this impairment, their time-intensive nature is not always feasible. Thus, we set out to develop a brief cognitive battery that is sensitive to poststroke cognitive impairment.METHODS:Neuropsychological testing was completed in a validation sample of 126 participants with chronic ischemic stroke (median days since stroke, 337 [interquartile range, 235–1057]) as part of StrokeCog, a prospective observational cohort study. This comprehensive 60-minute cognitive battery contained 9 tests covering 5 cognitive domains. A partial least square regression analysis informed the selection of a brief, 15-minute battery of 4 tests (StrokeCog-15) covering 4 cognitive domains: language, memory, working memory, and processing speed/executive functioning. We then compared StrokeCog-15 with Montreal Cognitive Assessment and an established 30-minute battery in its ability to detect cognitive impairment as identified by the comprehensive battery. Finally, we assessed the utility of StrokeCog-15 in an external validation sample of 61 participants (median days since stroke, 210 [interquartile range, 193–230]) enrolled in the parallel Stroke-IMPaCT study.RESULTS:Cognitive impairment was common, occurring in 50% (n=61) and 66% (n=40) of the 2 cohorts. Deficits occurred most frequently in the memory and processing speed/executive functioning domains. In the derivation sample, StrokeCog-15 demonstrated high sensitivity (0.97) and adequate specificity (0.78) in detecting cognitive impairment on the comprehensive battery, outperforming both Montreal Cognitive Assessment (sensitivity, 0.77; specificity, 0.73) and the 30-minute battery (sensitivity, 0.97; specificity, 0.35). StrokeCog-15 similarly demonstrated high sensitivity (0.93) and adequate specificity (0.67) in the validation sample.CONCLUSIONS:A brief 15-minute battery of tests has high sensitivity to detect cognitive impairment as identified on a longer neuropsychological test battery. StrokeCog-15 assesses multiple cognitive domains commonly impacted by stroke and represents an efficient yet effective means to identify chronic poststroke cognitive impairment