Stuart E. Mirvis MD, Presenter: Nothing to Disclose

1) Differentiate between true traumatic aortic injuries and anatomic variants that mimic aortic injury. 2) Learn the spectrum of aortic injuries and how their management is influenced by the type and extent of pathology. 3) Use various CT – angiographic features of aortic aneurysms of different etiologies and prognosis. 4) Recognize the signs of impending or current aortic aneurysm rupture.

This lecture describes the spectrum of true and false aortic aneurysms. Traumatic aortic pseudoaneurysm usually occurs from high-speed deceleration. Both frontal and side vehicle impact can produce the injury indicating shearing as the major mechanism. Individuals who sustain complete transections usually die at the trauma scene. The exact number of people with aortic injury surviving to reach medical care is actually not known since some injuries are never diagnosed. The chest radiograph is sensitive to the presence of an abnormal mediastinal contour periaortic hemorrhage and pseudoaneurysm, but is very non-specific with many studies appearing abnormal for non-trauma reasons. While many Emergency Departments obtain chest radiographs on all major blunt trauma patients, many are now obtaining screening total body MDCT studies initially. Contrast-enhanced MDCT has extremely high sensitivity for detection of aortic injury. Injuries vary from intimal flaps, intramural hematoma, contour abnormalities, and various sized pseudoaneurysms. All but very minor injuries are associated with periaortic blood. In about 15% of patients hematoma extends to the diaphragmatic crura and may be first noted on abdominal CT. Also, large pseudoaneurysms may compress the aortic lumen enough to decrease downstream pressure producing a small aortic caliber. For the past several years stent-grafts have successfully replaced open surgery for injury management with few complications. Complications that do occur include migration, collapse, inadequate coverage and endoleak. Most true aneurysms of the aorta result from atherosclerosis. Other etiologies include mycotic, cystic medial necrosis, Marfan syndrome, or a genetic predisposition such as a connective tissue disorder. MDCT signs of aneurysm rupture include contrast extravasation, adjacent high attenuation hemorrhage, “draped aorta” sign over the vertebral bodies, and a cresent of high-attenuation contrast within a mural thrombus. At

Mirvis, S, Traumatic Aortic Injuries.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/11000650.html