Bihemispheric decreases of regional cerebral blood flow in dementia: Correlation with age‐matched normal controls

Regional cerebral blood flow (rCBF) was measured by the xenon 133 inhalation method in 20 patients with senile and presenile dementia, and values were compared with flow data obtained in a series of 44 age‐matched normal controls. The rCBF was reduced in patients with both presenile and senile dementia, and the degree of decrease exceeded the age‐related rCBF decline in normal subjects. Similar rCBF reductions were observed in the left and right cerebral hemispheres and in general were homogeneously distributed in the various areas. The rCBF reductions in normal aging and in dementia may be associated with similar underlying cerebral morphological changes. Our findings suggest that the greater rCBF decreases in dementia compared with the values in age‐matched controls may quantitatively reflect more severe pathological alterations in the brains of patients with intellectual deterioration.