Side view 2D angiogram of the thoraco-abdominal aorta and iliac junction (left and right) and the frontal 3D CT angiogram of a 63-year-old male patient. The scan shows the presence of an aneurysm of the ascending aorta. An aneurysm is a blood-filled dilation in a blood vessel wall. If left untreated, the blood vessel can rupture. Risk factors for aneurysm include smoking, high blood pressure, infection and atherosclerosis (hardening of the arteries).