Hematogenous dissemination to the brain occurs frequently with bronchogenic carcinoma ( BGCA ). Advocates of computed tomographic (CT) scanning have proposed the use of CT scanning of the brain as a screening procedure to exclude metastasis. To establish CT's appropriate role, we have retrospectively reviewed patients who had CT scanning of the brain during the initial staging and evaluation of BGCA . Clinical factors indicative of metastatic disease, both organ-specific and nonorgan -specific, were extracted from the history, physical, and laboratory data. Eighty-nine patients were studied. Sixteen patients had abnormal CT scans of the brain (18 percent). Only nine of the 16 had evidence of central nervous system (CNS) disease on history or physical examination. All 16 patients had strong clinical indications of disseminated disease. With completely normal clinical examinations, no abnormal CT scans were identified. Among patients with three or more clinical abnormalities present, an abnormal CT scan occurred in 37.5 percent (12 of 32). The clinical examination is a sensitive indicator of metastatic CNS disease as identified by the CT scan. Both organ-specific and nonorgan -specific findings are important indicators of CNS metastatis .