Posttreatment Follow-Up MR Imaging Biomarkers of Collateral Status Are Associated with Short-Term Outcomes in Large-Vessel Acute Ischemic Stroke

BACKGROUND AND PURPOSE: FLAIR hyperintense vessels (FHV), quantified using the National Institutes of Health (NIH)-FHV score (NFS), and the SWI brush sign (SBS) are MRI markers associated with hemodynamic impairment in acute ischemic stroke (AIS). We aimed to evaluate the prognostic significance of posttreatment NFS and SBS in patients with anterior circulation large-vessel occlusion (AIS-LVO), including those with successful reperfusion. MATERIALS AND METHODS: We retrospectively analyzed 273 patents with AIS-LVO with in-hospital follow-up MRI. NFS and SBS were evaluated and correlated with clinical outcomes including NIHSS shift (≥4-point improvement) and hemorrhagic transformation (HT). The Spearman correlation and logistic regression were performed, adjusting for clinical covariates. Analyses were repeated in the successfully reperfused subgroup of 181 cases (modified TICI [mTICI] ≥2b). RESULTS: FHV and the SBS were observed posttreatment in 38% and 20% of patients, respectively. NFS and SBS were positively correlated (ρ = 0.54, P < .01). NFS inversely correlated with NIHSS shift (ρ = –0.27, P < .01) and reperfusion grade (mTICI; ρ = –0.32, P < .01). NFS was independently associated with worse NIHSS shift (OR, 0.64; P < .01) and reduced odds of HT (OR, 0.76; P < .01). Among patients with successful reperfusion, 20% of mTICI 3 cases showed FHV. In this subgroup, NFS remained predictive of poor NIHSS shift (OR, 0.57; P = .01). SBS alone was not independently associated with outcomes. CONCLUSIONS: NFS on posttreatment MRI is a robust imaging biomarker of persistent perfusion deficits and early neurologic outcome, even after successful reperfusion. SBS may reflect complementary collateral dynamics but showed limited independent prognostic utility.