Coloured computed tomography (CT) scan of the thoracic aorta of a 68-year-old female patient with cardiac failure. At centre, the ascending thoracic aorta is bulging, a condition known as an aneurysm. If left untreated, the blood vessel can rupture. Risk factors for aneurysm include smoking, high blood pressure, infection and atherosclerosis (hardening of the arteries). The scan also shows the presence of atherosclerotic plaques over the thoracic aorta.