[Cerebral blood flow studies using N-isopropyl I-123 p-iodoamphetamine in cerebral ischemic lesions].

Eighteen patients were studied for cerebral blood perfusion abnormalities using N-isopropyl I-123 p-iodoamphetamine (IMP) and rotating dual gamma camera emission computed tomography (ECT). All were stroke patients, 10 with cerebral vasospasm after an aneurysmal rupture, 3 with an occlusion of the middle cerebral artery, 2 with an occlusion of the internal carotid artery (IC), one with an IC stenosis, one with Moyamoya disease and one with RIND. Four patients had extracranial-intracranial (EC-IC) bypass operations. In three of them, CBF studies were done before and after bypass surgery. An arterial line was placed in the left radial artery and connected to a Harvard pump. IMP (1.5-3 mCi) was injected into an arm vein while at the same time an arterial blood sample was withdrawn at a constant speed for 5 minutes. Scanning was started 35 minutes after IMP injection. After a scan, multiple transverse, coronal and sagittal section images were reconstructed with a minicomputer. We determined the values of regional CBF in the regions of interest using an image. Transmission computed tomography (CT) studies were performed on the same day. In eight patients, CBF study by 133Xe inhalation method (NOVO cerebrograph) was done. ECT showed diffuse low perfusion in two patients and focal low perfusion in 16 patients while CT showed abnormalities in 9 patients (50%). ECT abnormalities were more extensive than CT abnormalities. The values of rCBF in the superficial brain determined by ECT were similar to those examined by the inhalation method (ISI). Significant increase in rCBF was observed after the bypass operations.(ABSTRACT TRUNCATED AT 250 WORDS)