Tomographic assessment of regional cerebral perfusion using intravenous I-123 HIPDM and a rotating gamma camera.

The feasibility of assessing regional cerebral perfusion using the new brain imaging agent N,N,N'-trimethyl-N'-(2)-hydroxy-3-methyl-5-(123I) iodobenzyl)-1,3-propanediamine 2 HCl (I-123 HIPDM) and single photon emission computed tomography (SPECT) was evaluated in normal subjects and patients with cerebrovascular disorders. Following intravenous injection, I-123 HIPDM was rapidly extracted from the circulating blood by the brain (6.7%) and other organs. Its intracerebral distribution, as tomographically assessed by SPECT with a rotating gamma camera, reflected the distribution of blood flow within brain structures (gray and white matter, basal ganglia, etc.). Asymptomatic patients with history of transient ischemic attacks or minor stroke and angiographic evidence of internal carotid artery occlusion showed large cortical areas of reduced I-123 HIPDM distribution with normal or slightly positive CT. After extracranial-intracranial bypass surgery, reperfusion could be shown in previously ischemic areas. This study indicates the clinical usefulness of using I-123 HIPDM and gamma camera SPECT for the functional evaluation of brain disorders.