CT images of blunt tracheal injury. Abnormal low density area adjacent to the trachea and emphysema

This study retrospectively examined the characteristics of computed tomography (CT) findings in patients with tracheal injuries. The clinical records, including bronchofiberscopic and CT findings, of patients with cervical subcutaneous emphysema; deep cervical emphysema or mediastinal emphysema, as revealed by a plane chest x-ray examination; or deep cervical emphysema, as revealed by a plane lateral neck x-ray examination were examined. All patients had been examined at our institution within the last 4 years. The CT images obtained in these cases were evaluated with regard to the presence of emphysema adjacent to the trachea, irregularities and discontinuities of the tracheal wall, abnormal low density areas (LDA) adjacent to the trachea, and the relative locations of the above findings. Sixteen patients were enrolled in the study. Tracheal injuries were diagnosed by bronchoscopy in 5 cases and not detected in the remaining 11 cases. CT images obtained in all 5 cases with tracheal injuries revealed an irregular and discontinuous tracheal wall, abnormal LDAs adjacent to the irregular and discontinuous regions, and massive emphysema adjacent to the abnormal LDAs. In the 11 cases without tracheal injury, the CT examinations revealed massive emphysema adjacent to the trachea, in 8 patients (73%), an irregular and discontinuous tracheal wall in 5 patients (45%), and abnormal LDAs in 2 patients (18%). These abnormal LDAs, however, were not adjacent to the irregularity and discontinuous regions of the tracheal wall. Irregularities and discontinuities in the tracheal wall, abnormal LDAs adjacent to these irregular and discontinuous regions, and massive emphysema adjacent to the abnormal LDAs are useful CT findings indicating the presence of a tracheal injury. (author)