PURPOSE: The angiographic demonstration of absent cerebral blood flow is presently considered to be the most reliable method of confirming brain death. The purpose of this study is to determine whether CT angiography (CTA) with spiral CT can rapidly and specifically establish a diagnosis of brain death. MATERIALS AND METHODS: A total of fifteen CT angiograms (brain death, n=9;severe coma, n=6 within 24 hours of the study) were obtained prospectively in 12 patients with an established clinical diagnosis; Two patients underwent repeated CTA. Twenty seconds after beginning the injection of contrast media (100 mL at a rate of 3 mL/sec), CT scanning (30 -second continuous exposure and 60 -mm length) was performed with a table speed of 2 mm/sec and a section thickness of 2 mm. For each case, the presence or absence of opacification of inter-nal carotid arteries (ICA), vertebral and basilar arteries (VBA), anterior cerebral arteries (ACA), middle cerebral arteries (MCA), posterior cerebral arteries (PCA), distal branches of cerebral arteries, and superficial temporal arteries (STA) was ascertained. RESULTS: Except in one clinically brain-dead patient, whose EEG was difficult to interpret due to excessive arti-facts, the distal branches of cerebral arteries did not opacify. STA, on the other hand, was always visible on both sides. In all brain-dead patients but three, the ICA and proximal ACA, MCA, or PCA escaped visualiza-tion. In the remaining three cases with large skull defect or skull fracture, however, CT angiography showed faint opacification of the ICA and proximal segments of cerebral arteries. Cerebral arterial flow was preserved in all six patients in whom there was no clinical evidence of brain death. CONCLUSION: CTA may be used as a confirmatory test for the determination of brain death.