The fate of hypoxic tissue on F-18-fluoromisonidazole positron emission tomography after ischemic stroke

We studied 24 patients up to 51 hours after ischemic stroke using F-18-fluo romisonidazole positron emission tomography to determine the fate of hypoxi c tissue likely to represent the ischemic penumbra. Areas of hypoxic tissue were detected on positron emission tomography in 15 patients, and computed tomography was available in 12 patients, allowing comparison with the infa rct volume to determine the proportions of the hypoxic tissue volume that i nfarcted and survived, The proportion of patients with hypoxic tissue and t he amount of hypoxic tissue detected declined with time, On average, 45% of the total hypoxic tissue volume survived and 55% infarcted. Up to 68% (mea n, 17.5%) of the infarct volume was initially hypoxic Most of the tissue "i nitially affected" proceeded to infarction, We correlated hypoxic tissue vo lumes with neurological and functional outcome assessed using the National Institutes of Health Stroke Scale, Barthel Index, and Rankin Score. Initial stroke severity correlated significantly with the "initially affected" vol ume, neurological deterioration during the first week after stroke with the proportion of the "initially affected" volume that infarcted, and function al outcome with the infarct volume. Significant reductions in the size of t he infarct and improved clinical outcomes might be achieved if hypoxic tiss ue can be rescued.