21 patients with clinical and CT diagnoses of intracranial tumor were studied by MRI (NMR) prior to and after administration of intravenous Gadolinium-DTPA. Resultant MRI images were compared with corresponding CT sections with respect to lesion detection, contrast enhancement, tumor delineation and visualization of perifocal edema. All intracranial lesions shown on CT were identified on MRI. Contrast enhancement in MRI images was achieved in 19 out of 21 patients, as it was also with CT. In these cases improved differentiation between tumor, perifocal edema and adjacent brain structures were obtained. In most cases sufficient visualization of perifocal edema in MRI required T2 weighted images (SE 1600/70) in addition to spin echo scans routinely performed prior to and after contrast medium (SE 400/30 or 800/30). No side effects were encountered following administration of Gadolinium-DTPA. The good tolerance and the efficacy justifies the use of Gadolinium-DTPA for contrast enhanced MRI imaging.