During a three-year period, fifty patients were evaluated for the possibility of dissecting aortic aneurysm using high-resolution computed tomography (CT). The diagnosis of dissection was made if two contrast-medium-filled channels were identified within the aortic lumen. Eighteen patients were diagnosed with CT as having dissecting aortic aneurysms. Eight patients were evaluated postoperatively and five of these patients had persistence of the double channel. Twenty-four patients had no evidence on CT of aortic dissection. Follow-up was obtained in all patients. There were no known false-negative diagnoses and one false-positive diagnosis. High-resolution CT offers an accurate, noninvasive means to evaluate patients for suspected dissecting aortic aneurysms.