Regional cerebral blood flow in normal individuals aged 40, 75 and 88 years studied by Tc-99(m)-d,l-HMPAO SPET

Age-related changes in cerebral blood flow (CBF) were examined with [Tc-99( m)]-d,l-hexamethylpropylene amine oxime (HMPAO), using a single photon emis sion tomography (SPET) gamma camera system equipped with a high resolution collimator, in 33 normal individuals in three age groups: 40 years old (n = 11), 75 years old (n = 9) and 88 years old (n = 13). A standard activity o f 1000 MBq [Tc-99(m)]-d,l-HMPAO was administered. Regional CBF (rCBF) (rela tive to cerebellar counts) was quantified in 28 grey and white matter regio ns. The mean rCBF of all the regions was 0.80 (95% confidence interval [CI] 0.77-0.83) in 40 year olds, 0.77 (0.74-0.80) in 75 year olds and 0.76 (0.7 3-0.78) in 88 year olds, rCBF in the hippocampus, angular and cingular gyri , and frontal association and motor cortices was 5-10% lower in the 75 and 88 year olds than in the middle-aged subjects (P < 0.05). The annual reduct ion in rCBF was 0.10% between the ages of 40 and 75 years and 0.13% between the ages of 75 and 88 years. The reduction in rCBF in the hippocampus rose from 0.14% between the ages of 40 and 75 years to 0.33% between the ages o f 75 and 88 years. The mean rCBF in all 33 individuals showed no sex-relate d differences. ((C) 2001 Lippincott Williams & Wilkins).