The purpose of this study was to describe the 16-slice detector spiral computer tomography (SCT) technique and imaging features of aortic aneurysms. We analyzed 21 patients documented aortic aneurysms, that underwent unenhanced and contrast-enhanced spiral CT with a 16-slice scanner (Sensation 16), and three-dimensional reconstructions were performed for CT scan images. The results showed that: (1) Aortic dissection (11 cases), included the true and false lumen (11 cases, 100%), intimal flaps (11 cases, 100%), intimal tear (9 cases, 81.8%) and thrombosed false lumen (5 cases, 45.5%); (2) Intramural hematoma, unenhanced CT depicted crescent-shaped areas with high attenuation extending along the walls of the aorta, no definable intimal flap, while contrast-enhanced CT showed no enhancement of attenuation in the crescent-shaped areas; (3) True aortic aneurysms (7 cases), CT revealed the size, range, thrombosis and calcification of all aneurysms; (4) Pseudoaneurysms (2 cases), the enhanced part of the inhomogeneous masses beside the aorta connected with the aorta shown on contrast-enhanced CT. Therefore, 16-slice detector SCT axial and three-dimensional images can exactly reveal the pathological and anatomical features of aortic aneurysms, and provide detailed imaging information for clinical therapy.