The utility of diagnostic tests for pituitary adenoma was compared in 12 patients. Endocrine and radiologic studies were always abnormal, even when neuro-ophthalmologic tests were normal. In most cases, both tomography of the sella turcica and CT scan revealed a mass in the region of the sella turcica. For more precise definition of suprasellar extension of the mass, metrizamide CT cisternography or tomographic pneumoencephalography with metrizamide provided similar details, although CT cisternography was much more easily done. Angiography provides a means to exclude an aneurysm or vascular malformation, a vascular tumor, or an aberrant course of the internal carotid artery.