Background: Indications for computed tomographic (CT) and magnetic resonance (MR) scans of the brain in psychiatric patients are not clearly defined. This survey attempted to refine indications suggested by an earlier survey.
Method: All brain scans ordered in a psychiatric teaching hospital were surveyed over a period of approximately 23 months. A revised order sheet provided information about the assumed need for scanning as well as indicated those factors from the previous survey most likely to reveal pertinent information. Scan results were later correlated with this information.
Results: Of 68 scans reviewed, 40 were normal, 16 equivocal, and 12 were abnormal. Cognitive decline and/or confusion were indications for 30 scans; 7 were abnormal, all meriting a clinical diagnosis of Alzheimer dementia. Only 1 of 12 scans to investigate a history of head injury was abnormal. Only 2 of 11 scans based on a history of seizures were abnormal; all had other possible indications. In one patient a prior stroke was confirmed, and in another, active multiple sclerosis. Ten of the group of 12 abnormal scans were found in patients over the age of 40 years, emphasizing the influence of age.
Conclusion: Revised indications based on this second survey were as follow: (1) The importance of new or unexplained focal neurologic signs was confirmed; (2) Scans are useful for bolstering a clinical diagnosis of Alzheimer disease; (3) A first psychotic break or personality change after the age of 50 years will require investigation; (4) Cognitive decline in a patient with a prior history of functional psychosis is most likely part of the psychosis rather than a confounding organic disorder; (5) Isolated seizures of long duration or abnormal EEG without other clinical findings are seldom associated with abnormal scans.