Traumatic Airway Injuries: Role of Imaging.

Airway Injuries are rare but often immediately life threatening. Incidence ranges from 0.5-2 % in blunt and 1-6 % in penetrating trauma. Upper airway injuries (UAI) are often clinically apparent and get shunted during the primary survey in the emergency department. Few UAI and majority of lower airway injuries (LAI) are occult on primary survey and need a high suspicion index. Clinically, the diagnosis of tracheobronchial injury is delayed in many patients because the airway column is maintained by the peribronchial tissue. Imaging in the form of MDCT, in conjunction with endoscopy, plays a role in delineating the exact site and extent of injury and ruling out associated vascular and esophageal injuries for definitive management of UAI. Chest radiographs and ultrasonography help raise suspicion of LAI by detection of pneumomediastinum, persistent pneumothorax and/or subcutaneous emphysema and should be followed up with multidetector computed tomography (MDCT) which is the mainstay of diagnosis. However, it requires careful evaluation of the airway tract and a thorough knowledge about the mechanism of trauma for detection of subtle injuries. Reconstructions in multiple planes and use of various post-processing techniques including minimum intensity projection (MinIP) images enhance the detection rate. The specific signs of LAI on CT include discontinuity in the tracheobronchial tree, focal intimal flap projecting in the lumen, focal soft tissue attached to the tracheal/bronchial wall, complete cut off of the bronchus/trachea and the fallen lung sign. We, hereby, illustrate the imaging spectrum of traumatic airway injuries in detail and discuss their management implications.