Abstract Number: Esoc2026a1879 Oxygen Extraction Fraction Imaging After Endovascular Treatment Correlates With Hypoperfusion and Functional Outcome in Lvo-Acute Ischemic Stroke

Abstract Background and aims The persistence of hypoperfusion areas in the brain on perfusion-weighted MRI is associated with functional outcome after endovascular treatment for large-vessel ischemic stroke. This study aimed to assess the value of measuring Oxygen Extraction Fraction (OEF) imaging after thrombectomy by evaluating its relationship with clinical outcome and hypoperfusion. Methods Single-center patients from the CHOICE trial assessing the value of post-thrombectomy IA rTPA in patients with large-vessel ischemic stroke who underwent successful endovascular treatment and had perfusion-weighted MRI within 48 hours were included (n=22). OEF and TMAX maps were derived from dynamic susceptibility contrast (DSC-MRI). Lesion ROIs defined on DSC-MRI were applied to extract OEF values and quantify hypoperfusion volume (Tmax6s). Volumes of tissue with elevated OEF were computed across intensity thresholds (0.00–1.00, step0.05). Associations with 90-day modified Rankin Scale (mRS) were assessed using Spearman correlation. ROC analysis evaluated the prediction of poor outcome (mRS 3–6). Results An OEF cutoff of 0.80 showed the strongest association with functional outcome among the tested OEF thresholds. The volume of tissue with OEF 0.80 was strongly correlated with hypoperfusion volume (Spearman’s ρ = 0.89, p 0.001). Both metrics demonstrated excellent discrimination for poor 90-day outcome, with an AUC of 0.91 for OEF 0.80 and 0.86 for Tmax6s (non-significant difference, Figure 1). Conclusions Elevated OEF identifies metabolically compromised tissue that closely corresponds to severe hypoperfusion and shows comparable prognostic performance for functional outcome. Conflict of interest Andrea Cabero-Arnold: nothing to disclose Figure 1 - belongs to Results