High resolution CT angiography in the direct diagnosis of cerebral aneurysms

By performing a rapid series of 1.5 mm slices, with high resolution CT angiography (angio-CT), after intravenous bolus injection of 100 ml of contrast medium, an image of the basal arteries similar to that of conventional angiography may be obtained. A consecutive series of 102 patients with suggested cerebral aneurysms were examined by angio-CT and, as a control, were also studied with selective four-vessel angiography and/or at autopsy. In 33 patients angiography or autopsy revealed no aneurysm; 69 patients were shown to have 76 aneurysms. The angio-CT was correctly negative in 30 patients (91%), falsely suggested in 2 (6%), and falsely positive in 1 patient (3%). Sixty-eight aneurysms (89%) of down to 3 mm in size were correctly demonstrated by angio-CT, 6 (8%) were correctly suggested, and 2 aneurysms (3%) escaped CT demonstration.