The results obtained from contrast-enhanced MRI in 21 patients with masses in the pineal region are reported. The use of gadolinium-DTPA results in intensive contrast uptake by the tumour; this produces better definition of the tumour and more exact delineation from neighbouring structures. This is of importance in judging resectability and in choosing the operative approach. During chemotherapy or radiotherapy, it provides reliable demonstration of the success of treatment and accurately demonstrates the size of the tumour and the presence of necrosis. On the other hand, histologic classification of pineal tumours is possible only occasionally.