Background: Collateral grade on cerebral angiography has great predictive significance for patient outcome, which is important to determine indication for endovascular therapy in acute ischemic stroke (AIS). Distal hyperintense vessels (DHV) on fluid-attenuated inversion recovery imaging (FLAIR) is a noninvasive and useful imaging marker that reflects leptomeningeal collateral flow. We investigated whether DHV in patients with AIS was associated with collaterals grade on cerebral angiography and clinical outcome after endovascular therapy.
Methods: We retrospectively reviewed patients with AIS who had internal carotid artery or middle cerebral artery occlusion in three comprehensive stroke centers from August 2011 to July 2015. We selected those who underwent FLAIR sequence before endovascular therapy. Presence of DHV was evaluated using a previously-published method. Collateral grades on pre-treatment cerebral angiography were assessed with the American Society of Interventional and Therapeutic Neuroradiology Collateral Grading System on angiography (grade 0-4). We analyzed the relationship between DHV and patient characteristics, collateral flow grade, and good clinical outcomes (modified Rankin Scale [mRS] of 0-2 at 90 days).
Results: A total of 38 patients (aged 71.7 ± 10.3 years; men, 71%; NIHSS score, 20 ± 6; median DWI-ASPECTS, 8) were included. DHV was detected in 29 patients (76%). Presence of DHV was significantly related to better collateral flow grade on angiography (2.5 vs. 1.3, p = 0.006), lower NIHSS score on day 7 (median, 7.8 vs. 16.3, p = 0.034), and higher rate of mRS 0-2 at 90 days (69% vs. 11%, p = 0.005), but was not related to DWI-ASPECTS (p = 0.819) or Thrombolysis in Cerebral Infraction (TICI) 2b/3 reperfusion rate (p = 0.128). In multivariate analysis, both presence of DHV (OR, 17.7; p = 0.013) and TICI 2b/3 reperfusion (OR, 21.3; p = 0.002) were independent predictors of mRS 0-2 at 90 days.
Conclusions: DHV on FLAIR is a marker of collateral flow status and might predict better clinical outcomes in patients with AIS. Using FLAIR sequence for evaluation of collateral status might be useful to select candidates for endovascular therapy.