Retrospective cohort analysis of early post treatment follow-up MRI biomarkers of collateral status associated with long-term outcomes in large vessel occlusion acute ischemic stroke.

BACKGROUND AND PURPOSE: FLAIR hyperintense vessels (FHV) on MRI, quantified using the NIH-FHV score (NFS), is associated with altered hemodynamics in acute ischemic stroke (AIS). We aimed to evaluate the long-term prognostic significance of post-treatment NFS in patients with anterior circulation large vessel occlusion (AIS-LVO). MATERIALS AND METHODS: We retrospectively analyzed 279 AIS-LVO patients with in-hospital follow-up MRI. NFS were evaluated and correlated with modified Rankin Score at 90-days (mRS-90) ≤ 2 as a long-term clinical outcome. Spearman correlation and logistic regression models were generated. A bidirectional algorithm based on Akike criteria was used to select clinical and imaging covariates in the final model. Analyses were repeated in all patients who underwent mechanical thrombectomy (MT) and a successfully reperfused subgroup (mTICI ≥2b). RESULTS: NFS was observed in 39% of the cases examined. All cohorts retained NFS as a significant predictor of unfavorable mRS 90, All treatment (OR 0.724, p < 0.01), All MT (OR 0.595, P < 0.01) and MT2b (OR 0.624, P = 0.02). All treatment multivariable regression model with NFS demonstrated an AUC of 0.867 compared to the covariates alone of 0.850, statistically significant by the Delong test, p = 0.047. CONCLUSIONS: NFS on post-treatment MRI is a robust imaging biomarker of persistent perfusion deficits and associated with decreased likelihood of successful long-term outcomes even after successful reperfusion.