Thoracic aortic aneurysms (TAAs) can be broadly divided into true aneurysms and false aneurysms (pseudoaneurysms). True aneurysms contain all three layers of the aortic wall (intima, media, and adventitia), whereas false aneurysms have fewer than three layers and are contained by the adventitia or periadventitial tissues. Multidetector computed tomographic (CT) angiography allows the comprehensive evaluation of TAAs in terms of morphologic features and extent, presence of thrombus, relationship to adjacent structures and branches, and signs of impending or acute rupture, and is routinely used in this setting. Knowledge of the causes, significance, imaging appearances, and potential complications of both common and uncommon aortic aneurysms, as well as of the normal postoperative appearance of the thoracic aorta, is essential for prompt and accurate diagnosis. Supplemental material available at http://radiographics.rsnajnls.org/cgi/content/full/29/2/537/DC1.
(c) RSNA, 2009.