Leukocyte infiltration in acute hemispheric ischemic stroke.

BACKGROUND AND PURPOSE The dynamics of leukocyte infiltration in human cerebral ischemia were studied using technetium-99m hexamethylpropyleneamine oxime (99mTc HMPAO)-labeled leukocyte brain single-photon emission computed tomography (SPECT). METHODS Twenty-two patients diagnosed as having hemispheric ischemic stroke were examined with 99mTc HMPAO brain SPECT for cerebral blood flow study and 99mTc HMPAO-labeled leukocyte brain SPECT for the study of leukocyte infiltration. Three patients with chronic hemispheric ischemic stroke received one examination. Nineteen patients with acute hemispheric ischemic stroke received their initial examination within the first after onset. Follow-up examinations were performed at intervals of 1-3 weeks whenever possible. RESULTS In patients with chronic hemispheric ischemic stroke, leukocyte infiltration was not seen in areas of perfusion defect. In patients with acute hemispheric ischemic stroke, leukocyte infiltration was seen in areas of perfusion defect during the acute stage, which persisted for no less than 5 weeks after onset and then declined. CONCLUSIONS A new method to study and monitor the process of leukocyte infiltration in acute cerebral ischemia using 99mTc HMPAO-labeled leukocyte brain SPECT is described. This method shows that leukocyte infiltration in acute hemispheric ischemic stroke is a dynamic process that persists for no less than 5 weeks and then declines.