Ten patients with encephalitis disseminata and 10 patients with cerebral ischemia underwent computed tomography and magnetic resonance imaging examinations. The results before and after the application of contrast media were compared. It is shown that T1-weighted MRI images, even after application of gadolinium-DTPA, are of little value for differential diagnosis of these diseases. In contrast, T2-weighted images did support the diagnosis of an acute stage of encephalitis disseminata versus acute ischemia. This was also true for lesions that had not been adequately depicted by computed tomography.