Noninvasive Regional Cerebral Blood Flow Measurements in Dementia

• Regional cerebral blood flow measured in patients with dementias (N = 60) using xenon Xe 133 inhalation was compared with measurements in healthy volunteers (N = 70). Volunteers were age-matched (N = 15); another group was younger. In normal aging, there is progressive, diffuse reduction of weight and flow of gray matter (F 1 ) but not of white matter. Therefore, age-matched control subjects are necessary in studies of dementia. In Alzheimer's disease (AD), F 1 shows bilateral and symmetrical reduction. The F 1 reduction correlated with atrophy estimated by computerized tomography, and duration and severity of dementia. In multi-infarct dementia (MID), bilateral hemispheric F 1 was patchily reduced. Cerebral vasodilator response to 5% carbon dioxide inhalation was reduced in patients with MID but was normal in patients with AD. Patients with Wernicke-Korsakoff's dementia showed normal values. Patients with dementia due to multiple sclerosis showed significant F 1 reduction compared with normal subjects. Standard behavioral activation in all patients with moderate to severe dementia failed to produce normal F 1 increases.