We utilized a novel MRI susceptibility method to quantify oxygen extraction fraction (OEF) in cortical vessels of 22 patients with acute stroke. The observed OEF ratio between affected and contralateral hemispheres depended on patient perfusion status, and tended to normalize (decrease) in follow-up scans on average 3 days later. Stroke cases with substantial perfusion-diffusion mismatch (indicative of potentially salvageable penumbra) showed the greatest OEF elevation (OEF ratio = 1.2 ± 0.1). Patients with large mismatch also showed an inverse relationship between OEF and relative cerebral blood flow (from dynamic susceptibility contrast), suggestive of mechanisms to maintain tissue oxygen metabolism even in ischemic tissue.
This abstract and the presentation materials are available to members only; a login is required.