Computed tomography (CT) scan of the abdomen of a 65 year old male patient with an abdominal aortic aneurysm. The aorta (white, down centre) is the body's main artery, it carries blood from the heart to the rest of the body. An aneurysm is a blood-filled dilation in a blood vessel caused by a weakened vessel wall. If left untreated aneurysms rupture and are often fatal. Treatment is by strengthening the aorta wall with a mesh stent. This patient has already had a stent (bright white tube at centre right) fitted to a weakened left renal artery.