Traumatic Pseudoaneurysm of the Descending Thoracic Aorta
A 39-year-old man presented with complaints of chest pain, dyspnea, and cough after a long-distance flight. He gave a history of having been involved in a major traffic accident 20 years ago in which he was run over by a truck, which resulted in extensive musculoskeletal injuries that necessitated several operations. He had been experiencing intermittent chest pain and dyspnea for 2 years. At the emergency department, a large upper-mediastinal mass was found on chest radiography (Figure, panel A). CT showed a large thoracic aortic aneurysm, and the patient was referred for cardiovascular MRI before surgery. This revealed a large aneurysm arising from the descending thoracic aorta distal to the origin of the left subclavian artery that measured 10 by 12 cm and traversed ≈10 cm of the proximal descending thoracic aorta. The aneurysm compressed on the left pulmonary artery and displaced the trachea to the right (Figure, panel B). Gradient echo cine imaging showed swirling blood within the cavity of the thin-walled aneurysm (Movie I). Contrast-enhanced magnetic resonance angiography was performed, and data postprocessing and reconstruction showed that the major arch vessels were uninvolved (Figure, panels C and D). The rest of the cardiovascular examination was normal. A chronic traumatic pseudoaneurysm was diagnosed, which involved the upper descending thoracic aorta, a common site for traumatic aortic transection. At surgery, a true transection of the descending aorta was found, with the 2 ends separated by the pseudoaneurysm. This was excised, and a Gelseal graft was used to bridge the transected ends. Histology of the aneurysm wall showed hyaline fibrous tissue, focal perivascular chronic inflammation, and large numbers of plasma cells, features that are in keeping with a pseudoaneurysm. The patient recovered fully and has remained asymptomatic 1 year after the surgical repair.
Cardiovascular MRI is the noninvasive investigation of choice for evaluation of aortic true and false aneurysms. 3D gadolinium-enhanced magnetic resonance angiography provides volumetric data for multiple reconstruction techniques, such as surface rendering (Movie II) and maximum-intensity projections, that afford detailed examination of the aneurysm and its relationship to other structures. In addition, cardiovascular MRI is able to provide useful preoperative information about cardiac anatomy and function in a single study.
The online-only Data Supplement, which contains two supplemental movies, can be found at http://circ.ahajournals.org/cgi/content/ full/112/15/e260/DC1.