Computerized tomography in intracranial metastases.

Two-hundred consecutive patients with suspected metastatic carcinoma and signs of cerebral dysfunction were evaluated by computerized tomography (CT). In ten patients, CT defined a nonneoplastic disorder, whereas in 190, CT defined a metastatic neoplasm. In 70 of these patients, the lesion was solitary; in 120, the lesions were multiple. In 52 patients, plain scan showed a solitary lesion, but multiple lesions were seen after contrast scan. In nine patients, the abnormality was seen only on postcontrast scan. One hundred lesions were of low density and 87 showed enhancement; 81 were of high density, usually surrounded by a low-density rim, and 78 were enhanced. There were no characteristic CT patterns of specific systemic carcinomas, but epidermoid carcinoma frequently appeared as a low-density lesion with a thin peripheral enhancing rim, and adenocarcinoma appeared as a dense, homogeneous, round, enhancing nodule. After treatment, enhancement was the most reliable sign of residual or recurrent tumor.