Current Concepts in Imaging Evaluation of Penetrating Transmediastinal Injury

Abstract

Penetrating transmediastinal injuries (TMIs) are injuries that traverse the mediastinum. These injuries are most commonly caused by firearms and knives. The investigation and management algorithms for TMI have undergone changes in recent years due to increasing evidence that computed tomography (CT) in useful in the evaluation of hemodynamically stable TMI patients. Initial investigation of TMI patients depends on the question of hemodynamic stability. In unstable patients, imaging (if any) should be limited to bedside radiography and focused ultrasonography. In hemodynamically stable patients in whom a mediastinal trajectory of injury is suspected, the primary imaging modality after radiography should be multidetector CT. CT is invaluable in the assessment of TMI due to its capacity to depict the injury track as well as demonstrate both direct and indirect signs of organ injury. On the basis of the suspected trajectory and specific findings, radiologists can play an essential role in determining future patient management and investigations for each mediastinal organ, thereby expediting appropriate investigation and treatment and avoiding unnecessary and sometimes invasive tests or surgery. The authors provide an up-to-date and evidence-based approach for the management of hemodynamically unstable and stable patients with suspected TMI, discuss management algorithms and CT protocols, and highlight common and uncommon imaging findings and diagnostic pitfalls associated with vascular, cardiac, esophageal, tracheobronchial, pleural, and pulmonary injuries. Online supplemental material is available for this article.

Imaging of penetrating thoracic trauma in a large Nordic trauma center

“…The use of intravenous contrast media is crucial to evaluate vessel and organ injury and active bleeding. CTA is the imaging method of choice in all penetrating trauma to rule out vascular injury (7,9,10,24). In this cohort, the standard protocol including arterial phase was rarely used.…”

“…The penetrating instrument and the force of impact differ greatly between firearm injuries and stabbings resulting in vast trauma energy variation. Extent of injury also depends on the affected tissue type (9–11).…”

Radiologic findings of thoracic trauma

“…They have been reported in 0.2%–8% of patients with blunt chest trauma. 1 , 9 , 13 – 15 Esophageal injury is extremely rare, because the esophagus is well protected in the mediastinum. Most esophageal injuries occur from penetrating chest traumas with a prevalence of 1%–1.6%.…”

Multidetector CT for Penetrating Torso Trauma: State of the Art

“…Wound trajectory in proximity to the esophagus or trachea is the primary indication for performing endoscopy, bronchoscopy, and esophagram, and these modalities can be obviated if the wound trajectory clearly avoids the aerodigestive tract (38,75). CT has a sensitivity of nearly 100% and specificity of 97.5% for injuries of the thoracic aerodigestive tract (85,86). Scans are considered inconclusive if there is mediastinal hematoma, pneumomediastinum, and cervical softtissue emphysema, and may strongly suggest injury if the track crosses or is proximal to vital structures (73) (Fig 4).…”