Abstract

Background. Fluid-attenuated inversion recovery vascular hyperintensity (FVH) and FVH-diffusion weighted imaging (FVH-DWI) mismatch are widely studied in acute ischemic stroke (AIS), yet their clinical and prognostic significance remains unclear. This study aimed to evaluate the clinical value of FVH extent and FVH-DWI mismatch in identifying patients likely to benefit from individualized therapy. Methods. From December 2017 to January 2025, AIS patients with subtotal / total occlusion of the internal carotid artery orthe M1 segment of the middle cerebral artery were enrolled. The extent of FVH (FVH-area) was assessed semi-quantitatively using a modified Alberta Stroke Program Early CT Score. FVH-DWI status was dichotomized into FVH-DWI mismatch and non–FVH-DWI mismatch based on FLAIR and DWI sequences. Functional outcome was assessed using the 90-day modified Rankin Scale (mRS). Multivariable logistic regression was used to identify predictors of FVH-DWI mismatch. Associations of FVH-area and FVH-DWI mismatch with outcomes were analyzed, followed by subgroup analyses stratified by FVH-DWI status. The relationship between FVH-area and outcome was further assessed using Spearman correlation. Results. Among 238 patients, multivariable analysis identified larger FVH-area (adjusted OR 1.35, 95% CI 1.08-1.68; P=0.008), higher Tan score (adjusted OR 3.29, 95% CI 1.87-5.79; P<0.001), and cerebral infarct patterns (territorial infarcts: adjusted OR 3.98, 95% CI 1.55-10.22; P=0.004; border zone infarcts: adjusted OR 0.27, 95% CI 0.11-0.72; P=0.008) as independent factors associated with FVH-DWI mismatch. FVH-DWI mismatch was associated with good functional outcome. Stratified analysis revealed divergent relationships between FVH-area and outcomes across subgroups. In the FVH-DWI mismatch subgroup, larger FVH-area correlated with good outcomes (P<0.05), while smaller FVH-area did so in non–FVH-DWImismatch subgroup (P<0.05). Spearman correlation showed no significant association between FVH-area and mRS in the FVH-DWI mismatch group (ρ=-0.148, P=0.081), but a positive correlation in the non–FVH-DWI mismatch group (ρ=0.604, P<0.001). Conclusions. FVH-DWI mismatch serves as a composite imaging biomarker that integrates information on perfusion status and tissue viability. It reflects collateral circulation and predicts clinical outcomes. In contrast, FVH-area shows a context-dependent relationship, with no correlation in FVH-DWI mismatch but a positive correlation with poor outcomes in non–FVH-DWI mismatch. These findings necessitate a paradigm shift in evaluating FVH, from assessing its area alone to interpreting it within its specific pathophysiological context. Key Words Stroke, Fluid-attenuated inversion recovery vascular hyperintensity, Diffusion-weighted imaging, Modified Rankin Scale; Functional outcomes