Brain Stem Diffusion-Weighted Imaging Lesion Score: A Potential Marker of Outcome in Acute Basilar Artery Occlusion

BACKGROUND AND PURPOSE: The benefit of recanalization in basilar artery occlusion (BAO) has been established. The baseline extent of brain stem damage may also influence the outcome. We investigated whether a baseline diffusion-weighted imaging (DWI) score may provide additional prognostic value in BAO. MATERIALS AND METHODS: We analyzed baseline clinical and DWI parameters in consecutive patients treated with endovascular procedures for acute BAO. Brain stem DWI lesions were assessed by using a semiquantitative score based on arterial territory segmentation. Outcome at 3 months was dichotomized according to the modified Rankin Scale (mRS) as favorable (mRS, 0-2) or unfavorable (mRS, 3-6). Spearman rank correlation tests assessed the correlation between DWI and clinical variables. Univariate and multivariate logistic regression analyses were used to identify clinical and MR imaging predictors of outcome. RESULTS: Twenty-nine patients were included. The brain stem DWI score (median, 3; range, 0-14) was correlated with the baseline National Institutes of Health Stroke Scale (NIHSS) score and the presence and length of coma (r = 0.67, 0.49, and 0.53, respectively; P < .01). Recanalization was achieved in 76%. A higher baseline NIHSS score (P = .02) and brain stem DWI score (P = .03), a lower Glasgow Coma Scale score (P = .04), and the presence of coma (P = .05) were associated with poor outcome in univariate analysis. Multivariate analysis showed that the brain stem DWI score was the only independent baseline predictor for clinical outcome (P = .026). CONCLUSIONS: Baseline brain stem DWI lesion score is an independent marker of outcome in BAO.