PURPOSE: To compare the usefulness of double-dose contrast-enhanced CT (DDCE-CT) and conventional contrast-enhanced CT (CCE-CT) in the detection of metastatic brain lesions. MATERIALS AND METHODS: Sixteen patients with brain metastases were evaluated with both CCE-CT and thinslice DDCE-CT. For CCE-CT, an initial injection of 100 ml contrast medium was given, and DDCE-CT with both 10-mm and 5-mm thickness was performed after the addition of an extra 100 ml of contrast medium. The numbers of metastatic lesions detected by CCE-CT and by DDCE-CT were compared, as were the findings of contrast-enhanced MRI (CE-MRI) and thin-slice DDCE-CT in seven patients who underwent both these procedures. RESULTS: Fourteen metastatic brain lesions were detected by CCE-CT, 22 by 10-mm-thickness DDCE-CT, and 36 by 5-mm thickness DDCE-CT. Thus, almost 2.6 times more lesions were detected by thin-slice DDCE-CT than by CCE-CT. Metastatic lesions were detected by 10-mm-thickness DDCE-CT in 16 patients and by CCECT in seven; in five, edema only was detected, while in four there were no detectable metastases. CCE-CT detected four lesions of less than 5 mm in diameter, while 10-mm-thickness DDCE-CT and 5-mm-thickness DDCE-CT detected seven and 18 lesions, respectively. Eleven lesions were detected by thin-slice DDCE-CT and 17 by CE-MRI in the seven patients who underwent both CE-MRI and DDCE-CT. The lesions detected only by CE-MRI were less than 5 mm in diameter and were discovered in the cerebellum or inferior temporal lobe. CONCLUSION: Thin-slice DDCE-CT was superior to CCE-CT in detecting metastatic brain lesions.