Metrizamide cisternography with both hypocycloid and computed tomography was performed on 23 patients with a sellar or a suprasellar lesion. The degree of an extrasellar tumour extension or the presence of an empty sella was detected precisely. The procedure was easy to perform and the side-effects were mild to moderate in most patients. When used carefully this diagnostic method provides valuable information when choosing the appropriate treatment for patients with sellar or parasellar lesions.