Associations between Fluid-Attenuated Inversion Recovery vessel hyperintensities and Alberta Stroke Programme Early CT Score and clinical outcomes in stroke patients with unknown time of onset: a sub-analysis from a randomized controlled trial

Background and Aims FLAIR vessel hyperintensities (FVH)-Alberta Stroke Program Early CT Score (ASPECTS) is an imaging marker but its clinical implications remain unclear. We estimated the correlation between FVH-ASPECTS and clinical outcomes in patients with wake-up stroke or unknown time of stroke onset. Methods The THrombolysis for Acute Wake-up and Unclear-onset Strokes with Alteplase at 0.6 mg/kg (THAWS) trial was a multicenter, randomized controlled trial conducted at 40 sites in Japan between 2014 and 2018. Patients with unknown stroke onset and DWI-FLAIR mismatch were randomly assigned to receive either intravenous alteplase (0.6 mg/kg) or standard medical treatment. FVH-ASPECTS, a semiquantitative scoring system assessing FVH prominence in the seven cortical ASPECTS regions, was evaluated for its association with favorable outcomes (modified Rankin Scale 0–2 at 90 days). The optimal FVH-ASPECTS threshold was determined using ROC analysis and its correlation with favorable outcomes was assessed. Results Among 131 patients (mean age, 76±13 years; 42% women), 71 received alteplase and 60 did not. Median NIHSS score was 7 (IQR 4–13), and median FVH-ASPECTS was 4 (IQR 2–4). ROC analysis identified FVH-ASPECTS 3 or more as predictive of favorable outcomes (sensitivity 80%, specificity 51%, AUC 0.717). A significant correlation was observed between FVH-ASPECTS 3 or more and favorable outcomes (adjusted OR 4.50, 95% CI 1.89–10.75; p<0.001). Conclusions FVH-ASPECTS could offer an indicator for achieving favorable clinical outcomes among stroke patients with unknown time of onset, with a threshold of 3 or more.