December 6, 2008

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
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)

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