Patterns of cerebral glucose utilization in depression, multiple infarct dementia, and Alzheimer's disease.

Patterns of local cerebral glucose utilization were determined in moderately to severely disabled patients with D (N = 7), MID (N = 6), and AD (N = 6), and in normal controls (N = 6), using positron emission tomography with the 18F-fluorodeoxyglucose method. Average global metabolic rate was decreased 30% in patients with AD, but overlap among the other groups reduced the discriminant value of this measure. In depressed patients, the cerebral metabolic pattern was normal, except for evidence of hypometabolic zone in the posterior-inferior frontal cortex which was of marginal statistical significance. In MID, focal metabolic defects were scattered throughout the brain and exceeded the extent of infarction. In AD, metabolism was markedly reduced in cortex, especially parietal cortex, but relatively preserved in caudate, thalamus, anterior cingulate gyrus, pre- and post-central gyrus, and calcarine occipital cortex, a pattern duplicating the degree and location of pathological and neurochemical alterations characteristic of this disorder.