Carotid-cavernous fistula. Demonstration of asymptomatic vascular "steal"

Abnormal distribution of cerebral vascular flow was studied in a patient who had a traumatic carotid-cavernous sinus fistula. Serial studies were performed using a method for determining relative cerebral vascular flow:99mtechnetium-diethylenetriamine pentaacetic acid (99mTc-DTPA) was injected intravenously and flow data were processed by a digital computer. Serial studies documented the occurrence of a vascular "steal" during temporary carotid occlusion; postoperative studies showed disappearance of the steal and obliteration of thiling arterial structures and capillary filling in the brain, and in demonstrating alteration in the cerebral circulation.