FLAIR distal hyperintense vessels as a marker of perfusion-diffusion mismatch in acute stroke

Background and purpose: Distal hyperintense vessels (DHV) on MRI FLAIR sequences in acute brain ischemia are thought to represent leptomeningeal collateral flow. We hypothesized that DHV are more common in acute stroke patients with perfusion-diffusion weighted mismatch (PDM) than in those without.

Methods: We performed a retrospective study of consecutive anterior circulation stroke patients who underwent multimodal MRI within 8 hours of onset. We correlated DHV occurrence with the presence or absence of PDM, and analyzed DHV correlates when angiography was available.

Results: Twenty-one patients with PDM and 28 without were included. On univariate analysis, there was no significant difference regarding demographic variables between the two groups, with the exception of a higher frequency of atrial fibrillation (33% vs. 7%; P = .02) and intravenous tissue plasminogen activator use (57% vs 25%; P = .03) in the PDM patients. The PDM group more commonly had DHV (85% vs 25%; P < .001). On multivariate analysis, DHV presence (odds ratio, 6.01; 95% confidence-interval, 1.08-33.29; P = .04) and vessel occlusion site (odds ratio, 3.17; 95% confidence-interval, 1.21-8.31; P = .01) were the only variables independently associated with PDM. Conventional angiography was useful correlating DHV presence and collateral flow in a subset of patients.

Conclusions: DHV may be a surrogate marker for PDM in patients with hyperacute ischemic stroke.