94 subjects, 64 with cerebral ischemia of varying severity and outcome, and 30 controls were studied with technetium-99m hexamethyl propylenamino oxime single photon emission computed tomography in order to evaluate the suitability of this technique in the assessment of cerebral ischemia. Decreased uptake corresponding to the side of clinical symptomatology and/or to CT lesion was found in 93 % of the patients with complete stroke and in 28% of the patients with transient ischemic attack. This procedure can be a useful tool in the routine examination of ischemic patients, although the mechanism underlying brain uptake is far from being completely understood and the possible quantitative evaluation of regional cerebral blood flow is worthy of further assessment.