FHV are linear serpentine hyperintensities on FLAIR MRI thought to occur from loss of normal endoluminal flow voids due to slow transit.  FHV has been previously associated with angiographic collaterals and may be associated with penumbra.  We compared presence of FHV to perfusion deficit on RAPID MRI using the FHV-ASPECTS score, previously shown to predict outcome in M1 occlusion post-thrombectomy. 

We retrospectively analyzed patients with M2 occlusion undergoing RAPID MRI from 2016-2018. We used the FHV-ASPECTs score to divide the MCA territory into 7 regions; one point was subtracted for each region containing FHV and scores ranged from 0-7.  FHV-ASPECTS score was applied to RAPID perfusion map (RAPID ASPECTs); one point was subtracted for every region containing Tmax >6.  We dichotomized FHV-ASPECTS into favorable (≤5) versus unfavorable (>5) as this cutoff has a sensitivity of 87.5% (95% CI 61.7-98.5%) and a specificity of 64.3% (95% CI 35.1-87.2%) for predicting mRS 0-2 at 90 days.   Cohen’s kappa was used to evaluate inter-rater reliability between FHV-ASPECTs score and RAPID ASPECTs score.  

49 MRIs were included.  FHV were present in 43 (87.8%) of MRIs and perfusion deficit in 38 (77.6%).  Median FHV-ASPECTS score was 4 (0-7) and median RAPID ASPECTs score was 4 (0-7).  40 (81.6%) had FHV ASPECTS ≤5 and 35 (71.4%) had RAPID ASPECTS ≤5.  Kappa for agreement between FHV ASPECTS ≤5 and RAPID ASPECTS ≤5 was nonsignificant at 0.39.