Traumatic Aortic Injury (TAI)

Fig.1: Portable chest radiograph shows widening of the superior mediastinum (two-sided arrow), deviation of the NG tube (arrowheads) and trachea to the right.
Fig.2: Axial CT with IV contrast shows a large periaortic hematoma (stars) displacing the NG tube (arrowhead) to the right.
Fig.3: Axial CT at the level below the arch demonstrates a pseudoaneurysm (red arrow) anterior to the true lumen (red arrowhead). Hematoma (stars) and NG tube (yellow arrowhead)

Radiographic Findings

• Widening of superior mediastinum (subjective 'eyeball' estimation)
• Blurring of aortic contour
• Deviation of nasogastric tube to the right
• Normal - not common but x-ray can be normal if there is no or minimal periaortic hematoma (Normal chest radiograph does not exclude TAI in a trauma patient with suspicious mechanism)
  

CT Findings

• Direct signs: Pseudoaneurysm, intimal flap, irregularity of aortic wall, pseudocoarctation, thrombus with in the wall
• Indirect sign: Periaortic hematoma (not isolated anterior mediastinal hematoma)

Do We Need Aortography?

• Studies of MDCT (16- and 64-MDCT) showed accuracy of near 100% using surgery or follow-up CT as standard references
• When a direct sign is present, TAI can be diagnosed confidently without aortography
• Aortography can be reserved for equivocal cases, evaluation of aortic branch vessels and endovascular therapy
  

Reference:
1. Kaewlai, et al. MDCT of blunt thoracic trauma. Radiographics 2008 (October)
2. Steenburg, et al. Acute traumatic thoracic aortic injuries: experience with 64-MDCT. AJR 2008 (November)