Changes of blood flow in the cerebral cortex after subcortical ischemic infarction.

The two-dimensional xenon-133 inhalation method was used to measure cortical blood flow in 16 patients with small subcortical ischemic infarcts and in 10 patients with larger cortical infarcts in the chronic phase of stroke. An abnormal hemispheric asymmetry of blood flow was seen, not only in patients with cortical infarcts, but also in those with subcortical infarcts. In the patients with subcortical infarcts, focal areas of reduced cortical blood flow were seen in the symptomatic hemisphere remote from the tissue destruction, usually including part of the noninfarcted frontoparietal cortex. The cortical dysfunction may have contributed to the clinical manifestations including aphasia, which was present in 14 of the 16 patients with subcortical lesions.