Evaluation of patients before transsphenoidal hypophysectomy for large intrasellar mass lesions has required bilateral internal carotid artery angiography. Using intravenous injection of contrast medium, a method has been developed to visualize the parasellar carotid arteries with rapid sequence sequential computed tomographic scanning. In 18 patients, the cavernous segments of the internal carotid arteries were well seen in 27 of 28 instances with technically complete examinations. The vascularity of the mass lesions and vascular encasement was also demonstrated.