Abstract
The authors studied age-related changes in brain volume and cerebral blood flow in neurologically normal subjects with and without risk factors for cerebral arteriosclerosis (hypertension, diabetes mellitus, ischemic heart disease, hyperlipidemia). Using computed tomography brain volume index (BVI; 100%×braun volume/cranial cavity volume) was calculated as an indicator of brain atrophy. Using xenon-133 inhalation method, initial slopw index (ISI) was calculated as an indicator of mean regional cerebral blood flow. The ISI was further corrected for brain atrophy and called cISI (cISI=ISI×BVI). In the subjecs with risk factors (7 men and 25 women), the BVI declined with age (BVI=105.8-0.181×age, r=0.601, p<0.001). While the ISI did not decline with age, the cISI declined with age (cISI=72.1-0.350×age, r=0.350, p<0.05) and was related to the BVI (BVI=87.2+0.137×cISI, r=0.454, p<0.01) in those subjects. In the subjects without risk factors (30 men and 27 women), the BVI declined with age (BVI=105.0-0.178×age, r=0.700, p<0.001). Both the ISI and cISI did not decline with age and the cISI was not related to the BVI.
