Relative efficacy of computed tomography and radionuclide scan in the diagnosis of organic brain syndrome.

Computerized tomography (CT) scan and radionuclide (Rn) scan findings on 77 psychiatric patients were compared to evaluate the relative efficacy of these two procedures in the diagnosis on intracranial disease. CT scan detected significant abnormalities in 23 patients (29.9%) while the Rn scan was positive in only five patients (6.5%). This is almost a fivefold difference in the detection rate of abnormalities between the CT and RN scan. Thirty-four of the 77 patients were diagnosed with organice brain syndrome (OBS) according to the criteria by Feighner et al. CT scan exclusively determined the contributing causes in 20 (58.8%) of these patients. In contrast, none of the Rn studies could exclusively contribute to a diagnosis of OBS. It is concluded that the routine use of both diagnostic procedures hardly seems justifiable in terms of patient benefit and increased cost.