Traumatic aortic injury: an imaging review.

Traumatic aortic injury (TAI) is a major cause of fatality in high speed deceleration injuries. It accounts for 10-20% of fatalities in blunt chest trauma. These injuries are usually related to high-speed motor vehicle and motorcycle collisions, pedestrian-motor vehicle collisions, and falls. Only 10-20% of patients who suffer TAI survive the initial injury and reach the emergency department. If left untreated, 30% die within 6 h, 40-50% die within 24 h, and 90% die within 4 months. A chronic pseudoaneurysm will develop in 2-5% of patients whose injury is not diagnosed. It is imperative, therefore, that these injuries are detected promptly and accurately. Symptoms and physical examination findings are nonspecific. External evidence of chest wall injury is present in 7-90% of cases, so that in up to 30% of the cases no apparent chest injury is identified on physical examination. Chest radiographs are very sensitive in detecting mediastinal hemorrhage, but have a low positive predictive value for aortic injury. The positive predictive value for chest radiography ranges between 5% and 20% for TAI. Aortography has been considered the gold standard for many years in the evaluation of TAI, but is time-consuming, labor- and resource-intensive, and invasive. Because of the shortcomings of physical examination and these more traditional imaging examinations, computed tomography (CT) has become increasingly utilized as a screening and diagnostic tool. Recent investigations have documented its high sensitivity and specificity in the detection of TAI. This article reviews the recent investigations of imaging evaluation of TAI, with a focus on helical CT.