Imaging description

Aortic transection is the most severe form of traumatic aortic injury. In the majority of cases, aortic transection involves all three layers of the aortic wall and results in such rapid exsanguination that the injury is fatal before the patient can present for imaging. Those transections which are seen at imaging consist of contained aortic rupture due to disruption of the intima and media with preservation of the adventitia. Direct CT signs of aortic transection include pseudoaneurysm or contained rupture, abrupt aortic caliber change, irregular aortic contour, or intimal flap (Figures 46.1–46.4). Visualization of frank contrast extravasation is rare. The most common indirect sign is mediastinal hematoma. Aortic injury is most common at the aortic root, the ligamentum arteriosum, and the diaphragm, as the relative fixation of the aorta at these sites creates vulnerability to the shear forces generated in blunt trauma [1, 2].