Regional cerebral blood flow measured with N-isopropyl-p- [123i] lodoamphetamine and its redistribution in ischemic cerebrovascular disease

Abstract

Background and Purpose: The relation between the redistribution phenomenon and regional cerebral blood flow and its clinical significance were investigated in stroke patients. Methods: Single-photon emission computed tomography studies using N-isopropyl-p-[123I] iodoamphetamine were performed on 16 patients (26 to 77 years old) with chronic infarction and 10 age-matched normal control subjects. Regional cerebral blood flow was quantitatively measured by a microsphere model, and the redistribution on delayed images was analyzed in ischemic lesions. Results: Supratentorial mean cerebral blood flow and the ratio of gray matter to white matter in normal subjects were 52.7±5.0 mL/100 g per minute and 2.34, respectively. Low-activity areas of ischemic lesions on early images were classified into two abnormal zones, an infarct area and a peri-infarct area. These regions were characterized by regional blood flow averaging 9 to 20 mL/100 g per minute and 22 to 41 mL/100 g per minute, respectively. Redistribution, which was minimally present in the infarct area, was markedly enhanced in the peri-infarct area. After bypass surgery, we observed a significant increase of blood flow (+22%) in the peri-infarct area. Conclusions: The data indicate that the redistribution phenomenon depends on the maintenance of a minimal blood flow that would sustain cellular function and that this phenomenon is useful to evaluate bypass surgery in patients with chronic infarction. © 1993, Stroke. All rights reserved.