Comparison of PET measurement of local brain glucose metabolism and CAT measurement of brain atrophy in chronic schizophrenia and depression

Using [18F]fluorodeoxyglucose and positron emission tomography (PET), the authors examined the regional brain glucose metabolism of six patients with chronic schizophrenia, six patients with chronic depression, and 12 normal control subjects. Three schizophrenic and four depressive patients had CAT scans that showed enlarged ventricles (ventricle-brain ratios higher than 9.0) and widened sylvian fissures. The PET scans of the schizophrenic and depressed patients did not differ significantly from those of the age-matched controls, and a previously reported metabolic "hypofrontality" was not confirmed. The patients with enlarged ventricles and widened sylvian fissures tended to have lower global metabolism.