A vascular aneurysm is a permanent, localized dilatation of a blood vessel at least 1 1/2 to 2 times the normal vessel diameter. The aorta is the most frequent site for aneurysms, with approximately 10% of aortic aneurysms located above the renal arteries in the thoracic segment. Thoracic aortic aneurysms (TAAs) are less common than abdominal aorta, however, detection of TAAs is increasing, perhaps due to an aging population, increased diagnostic capability or an increase in prevalence.