The oxygen consumption by brain tissue can be measured with oxygen extraction fraction (OEF), a potential indicator of the occurrence of stroke. A single shot asymmetric spin echo (ASE) EPI sequence was implemented for OEF measurement in stroke patients. Increased OEF corresponded with the decrease blood flow in the ischemic brain region, as reported in the previous literature. ASE EPI showed the potential to provide quantitative OEF maps with good brain coverage and without the need of gas challenges. The measurement of OEF may provide a better assessment of viable brain stroke after a stroke attack for potential treatment.