Normal Distribution of Regional Cerebral Blood Flow Measured by Dynamic Single-Photon Emission Tomography

Abstract

Summary: Regional CBF (rCBF) was measured quanti tatively using the inert-gas washout technique with xenon-133 and single-photon emission computed tomog raphy. Tomographic data were reconstructed by filtered back projection, and flow was calculated according to the double-integral method, Ninety-seven subjects ranging in age from 20 to 59 years received a single examination; eight of these received a second examination within 1 h of the first; seven others received a second examination separated from the first by 1-10 days. Transverse-section images were obtained at 2, 6, and 10 cm above and par allel to the canthomeatal line (CML). Cortical gray matter flows were obtained from 12 brain regions in the slice 6The measurement of regional CBF (rCBF) in hu mans began with the pioneering work of Kety and Schmidt (1945) in which they employed the nitrous oxide method to measure mean hemispheric blood flow. A decade later, Lassen and lngvar (196 1) adapted this technique to the external detection of radioactive inert-gas tracers, namely 85Kr. By using multiple detectors, multiple brain regions could be examined for abnormalities in rCBF. Advances in tracer technology led to the widespread use of 1 33 Xe in place of 8 5Kr, while advances in detectors, col limation, and data analysis led to ever increasing number of probes (up to 254) and thus regions of brain subjected to rCBF analysis (Veall and Mallett, 1966; Obrist et aI., 1975; Risberg et aI., 1975; lngvar, 1976; Sveinsdottir et aI., 1977; Lassen et aI. , 1978). where there was no difference. Flow was higher in women than in men and declined mildly with age for both sexes (slope = -0.33 mllmin/lOO g/year; p < 0.05).

Quantification of regional cerebral blood flow with IMP-SPECT. Reproducibility and clinical relevance of flow values.

“…Using the xenon-133 inhalation technique, Gur et al 30 and Shaw et al 31 observed significantly higher values in women than in men. In the subjects investigated by Devous et al, 21 females of different ages had higher hCBF and rCBF values than age-matched males; significant differences were found in the 20-29-and the 30-39-year-old groups. Yoshii et al 32 reported significantly higher CMRglu in young and elderly females than males.…”

“…20 Devous et al 21 found a mean±SD gray matter blood flow of 71 ±12 ml/100 g/min using xenon-133 SPECT. Our calculated mean (67-68 ml/100 g/min) and standard deviations of gray matter blood flow closely resemble those obtained with established three-dimensional techniques.…”

Gender Differences in Human Brain: A Review

“…Increased level of Glc spectra was detected in female orbital frontal cortex [115]. Functional brain imaging studies (single-photon emission tomography and positron emission tomography (PET)) indicate sex differences in brain metabolism, particularly in global and regional cerebral blood flow and glucose consumption [75,[118][119][120][121][122][123][124]. Cognitive activity resulted in increased flow of blood to the cerebral hemispheres.…”

Age‐related cerebral perfusion changes in the parietal and temporal lobes measured by pulsed arterial spin labeling

“…Finally, the T1-weighted structural images were spatially normalized and the same transformations were applied to the CBF maps. During this process, CBF maps got interpolated to a voxel size of 2 Â 2 Â 2 mm 3 . The normalized CBF maps were smoothed with an isotropic 12-mm full width at half-maximum Gaussian kernel to normalize the distribution of perfusion data as required within the framework of the subsequent statistical analyses and inference.…”

“…However, its role in healthy ageing is not well understood. Early investigations of age-related CBF changes using positron emission tomography (PET) or single photon emission computed tomography (SPECT) found a general decline of CBF in whole brain or grey matter (GM) (3,4). More recent PET-based studies explored CBF in selected regions of interest (5,6) and stressed the confounding influence of partial volume effects (7,8) due to atrophy in the ageing brain.…”