Abstract W P4: Prediction of Antegrade Flow Using FLAIR and GRE in Hyperacute Stroke

Background: Recanalization of an occluded vessel has been shown to improve clinical outcomes in hyperacute ischemic strokes. Presence of antegrade flow across the occluded vessel has been regarded as one of predictors of successful recanalization after endovascular treatment. We aimed to predict antegrade flow non-invasively using FLAIR and GRE images. Methods: We collected patients who had acute ischemic stroke within 6 hours from onset and 50 patients who underwent endovascular treatment were included. All patients had ICA or MCA steno-occlusion. FLAIR hyperintense vessels(FHVs) were defined as linear or curved hyperintensity were observed on FLAIR. Dark intensity on GRE(GRE vein) and sulcal effacement(SE) were also assessed. We divided patients into 2 groups according to FHV, GRE vein and SE: (1) Group 1 = patients with insular FHVs(M2 and/or M3 of MCA) and distal SE or GRE vein(beyond M4 area); 2) Group 2 = patients who not allocated into group 1. We evaluated angiographic findings and clinical outcome. Results: Of 50 patients, 25(50.0%) patients had insular FHVs and distal SE or GRE veins. Antegrade flow on DSA were more frequently observed in group 1(22 [88%] vs. 5 [20%], p<0.001). Group 1 showed more successful recanalization than group 2 (22[88%] vs. 12[50%], p=0.004). Clinical outcomes were also better in group 1. Early neurological improvement(ENI; ΔNIHSS at 24 hours≥8 or NIHSS at 24 hours≤2) and favorable outcome at 3 months(mRS 0-2) were more frequently seen(ENI, 13[52.0%] vs. 2[9.1%], p=0.002; favorable outcome, 19[79.2%] vs. 3[12.0%], p<0.001). Nine patients in group 1 showed diffusion lesions in the insular area (i.e. FHV (+) within the infarct). We performed subgroup analysis. Diffusion volume was not different (52.1[6.4-95.9] vs. 62.2±6.9mL, p=0.492). Antegrade flow and successful recanalization were more common in FHV(+) within the infarct group and clinical outcome was also better. Conclusion: FLAIR-GRE sign (insular FHVs with distal SE or GRE vein) may be a marker for antegrade flow in hyperacute stroke. FLAIR-GRE sign is associated with higher recanalization rates and good clinical outcome.