Cerebral infarction is a ischemic syndrome of specific vessels, depends not only on the site of the occlusion but on previous brain damage, collateral circulation, and variation of the region supplied by a particular artery, including aberrations in the circle of Willis.

SPECT of regional cerebral blood flow was performed using ^99mTc-HMPAO uptake in 27patients with brain infarcts during the acute and subacute period(Onset to Days 33).

All patients had normal brain CT prior to SPECT. Twenty five of 27 patients had abnormal ^99mTc-HMPAOfCBF SPECT. Twenty-four had unilateral involvement and the other one had bilateral involvements. Sixty-eight percents of the defects were found in the left cerebral hemisphere, according to the distribution of the lesions(total number:39 lesions), fifteen were in the frontal, thirteen in the pariental, and the remainders were elsewhere. Twenty(74 percents) had a significant correlation between clinical signs and scan lesion site.

Brain SPECT has been used efficiently in the evaluation of cerebral infarcts and ischemia without evidence of brain CT lesions, brain SPECT allows us to look accurately and effectively at the functional abnormalities resulting from small structural defects.