The aorta is a main blood vessel in the chest and abdomen. An abdominal aortic aneurysm (AAA) is an abnormal enlargement of the aorta in the abdomen; it is often asymptomatic, meaning that it causes no symptoms. Monitoring the size and growth of the aneurysm is important because it is often fatal if the aneurysm ruptures. This is more likely in individuals with AAA that grows more than 2 mm per year. Treatment should be considered when an individual without symptoms has an AAA larger than 5.4 cm in men and 4.9 cm in women.
There are three imaging examinations that are usually appropriate for people without symptoms with AAA: ultrasound with aorta blood flow measurements (the most widely used test), CT angiography of abdomen and pelvis with intravenous contrast, and MR angiography of abdomen and pelvis with intravenous contrast. For people without symptoms in whom contrast should not be used, CT or MRI tests of the abdomen and pelvis may be appropriate.
For more information, see the Abdominal Aortic Aneurysm (AAA) page.