Studies on cerebral hemodynamics by single photon emission computerized tomography, 1

Cerebral blood flow (CBF) was studied in 47 normal volunteers between 25 and 82 years of age in the resting state by single photon emission computerized tomography (SPECT) with Xe-133 inhalation method. To investigate the reproducibiilty, 5 patients received the second SPECT examination within one hr after the first SPECT (Group I). Six other persons received it 7 to 26 days after the first SPECT (Group II). In addition, SPECT with N-isopropyl-p-I-123 iodoamphetamine (I-123 IMP) was performed in 5 patients for the comparison. Five transverse sections were assigned at 1, 3, 5, 7, and 9 cm above and parallel to the orbito-meatal line (OML). Cerebellar flows were obtained from a slice 1 cm above the OML (slice 1) and mean hemispheric flows were obtained from slices 3 cm (slice 2), 5 cm (slice 3), 7 cm (slice 4), and 9 cm (slice 5) above the OML. The mean CBF derived from slice 2 was significantly higher than that from slice 3, while the mean CBF from slices 4 and 5 was significantly lower. CBF values in the region of the cerebellum and white matter obtained from Xe-133 SPECT tended to be greater than I-123 IMP SPECT values. The right-sided regional CBF values were slightly higher than the left in the anterior and middle cerebral artery territories, whereas no asymmetries were obtained in the posterior cerebral artery territory, basal ganglia or the cerebellum. CBF showed significant negative correlation with advancing age and a reduction of CBF values with advancing age was greater in the middle cerebral artery territories bilaterally when compared with other regions. Both Groups I and II showed a good reproducibility, although the CBF values obtained in the second examination were slightly lower than that obtained in the first. (N.K.)