Association between MR-derived oxygen extraction fraction and neurological improvement at 24-72 h after successful reperfusion.

Oxygen Extraction Fraction (OEF) reflects metabolic changes in cerebral tissue resulting from ischemia and serves as a biomarker of tissue viability in hyperacute stroke. This study evaluated the association between infarct OEF and neurological improvement in ischemic stroke patients following successful endovascular reperfusion therapy, defined by the modified Thrombolysis in Cerebral Infarction (mTICI) score. Infarct OEF index values were extracted from OEF maps using manually delineated infarct regions, 24-72 h post-reperfusion in fifty ischemic stroke patients. Multivariable linear regression analyses analysed the association between neurological improvement defined as improvement in the National Institutes of Health Stroke Scale (ΔNIHSS) and infarct OEF. Linear regression showed a non-significant association between infarct OEF index and ΔNIHSS (β = -0.369, 95 % CI = -3.265-2.526, p = 0.796), and a significant interaction of infarct OEF index and reperfusion status (β = 4.288, 95 %CI: 0.377-8.199, p = 0.033) with ΔNIHSS. A subgroup analysis of the patients with full angiographic reperfusion (mTICI 3) showed a significant association between infarct OEF index and ΔNIHSS (β = 4.937, 95 %CI: 0.188-9.685, p = 0.043). The results demonstrate that post-thrombectomy, OEF in conjunction with reperfusion status could be a surrogate marker of tissue viability in acute post-reperfusion period. Clinical trial registration number for Post-Reperfusion Pathophysiology in Acute Ischemic Stroke (PRAISE): ACTRN12624000629538.