N-isopropyl-p-[¹²³I]iodoamphetamineとSPECTによる断層脳血流画像の臨床的有用性　^81mKr画像との比較検討

抄録

Local cerebral blood flow in 28 patients (aged from 13 to 71) with cerebrovascular disorders was studied 37 times by single photon emission computed tomography (SPECT) using N-isopropyl-p-[¹²³I] iodoamphetamine (IMP), and compared with findings of X-ray computed tomography (CT) and ^81mKr (Kr) perfusion images. There were three patients with occlusion of the internal carotid artery, two with stenosis of the internal carotid artery, six with occlusion of the middle cerebral artery, five with occlusion of the bilateral vertebral arteries, five with moyamoya disease, two with aortitis syndrome, and five with cerebral arteriovenous malformation. Examinations were performed using a rotating gamma camera with dual heads in both SPECT-IMP and SPECT-Kr. In the IMP study, both SPECT and planar images were obtained 30 and 120 minutes after intravenous injection of IMP. SPECT-Kr was performed by continuous infusion into the ascending aorta of ^81mKr generated by an ⁸¹Rb-^81mKr generator. Sampling time was about 20 minutes in 22 examinations and about 10 minutes in 15 examinations by SPECT-IMP, and about 4 minutes in all the examinations by SPECT-Kr. SPECT-IMP images 30 minutes after injection showed low perfusion area in all but four examinations in three patients: one patient with transient ischemic attack alone and two patients with aortitis syndrome. In 26 of the 33 examinations, SPECT-IMP images 30 minutes after injection revealed more extensive or obvious low perfusion areas than the low density lesions in X-ray CT, and low perfusion even in the areas without low density lesions. In all of the 33 examinations, low perfusion areas shown in SPECT-IMP images 30 minutes after injection became obscure after 120 minutes. In respect to representation of local cerebral blood flow, SPECT-IMP images 30 minutes after injection seemed to be better than after 120 minutes. In 26 of the 33 examinations, low perfusion areas in SPECT-Kr images were more extensive and obvious than in SPECT-IMP images. However, SPECT-IMP images seemed to show a more definite anatomy than SPECT-Kr images. The nidus of a cerebral arteriovenous malformation was shown to be a low perfusion area in SPECT-IMP images, but appeared as a high perfusion area in SPECT-Kr images. It is likely that SPECT-Kr images showed mainly intravascular flow of the nidus. In comparison with SPECT-Kr, SPELT-IMP was considered to be an easy and noninvasive three dimensional study of local cerebral blood flow.