Diaschisis and acetazolamide reactivity in brainstem infarction.

Regional cerebral blood flows (rCBF) were studied in 6 patients with lateral medullary infarction and 4 patients with pontine infarction, using stable xenon computed tomography method. In lateral medullary infarction, the rCBF and acetazolamide reactivity were decreased in the ipsilateral cerebellum and the rCBF was decreased with normal acetazolamide reactivity in the contralateral frontal lobe in one patient accompanying ipsilateral cerebellar infarction. rCBF was decreased with normal acetazolamide reactivity in the cerebellum in 3 patients, and both rCBF and acetazolamide reactivity were decreased in the whole brain in 2 patients. In pontine infarction, rCBF was decreased in ipsilateral frontal lobe and contralateral cerebellum in one patient, rCBF was decreased in the cerebellum with normal acetazolamide reactivity in the other patients. The hypoperfusion with normal acetazolamide reactivity was considered to be due to diaschisis. The rCBF decrease in the remote areas in patients with brainstem infarction was considered to be due to diaschisis or underlying arteriosclerosis.