Evaluation of tracheobronchial angles on computed tomography in patients with pneumomediastinum

Purpose: To investigate tracheobronchial diameters and tracheobronchial bifurcation angles on computed tomography (CT) in patients with pneumomediastinum.Materials and methods: CT scans of 63 patients with pneumomediastinum (PP) and 63 patients with normal CT findings (PN) were retrospectively evaluated in the Radiology Archives of our hospital. In PP, the extent of mediastinal air on CT images was visually classified into three grades. Thoracic anteroposterior distance (TAPD) and transverse thoracic distance (TTD), anteroposterior (AP) diameters of the trachea and bronchi, tracheal length (TL), right main bronchus angle (RMBA), left main bronchus angle (LMBA), subcarinal angle (SCA), and interbronchial angle (IBA) were measured on CT images in all patients. All measurements were compared between patients with and without pneumomediastinum.Results: A significant sex-related difference was observed in thoracic AP diameter and left main bronchus diameter in the PN group. Among PP, 22.2% (n=14) were grade 1, 30.2% (n=19) were grade 2, and 47.6% (n=30) were grade 3.Tracheal length and left main bronchus diameter were higher in PN patients compared to PP patients. The mean SCA was 75.06±23.40° in the PP group and was significantly greater than in the PN group (p=0.001). LMBA was significantly higher in the PN group compared with the PP group (p=0.003).Conclusion: Individuals with a narrower LMBA, shorter tracheal length, larger thoracic AP diameter, and wider SCA may be at greater risk of developing pneumomediastinum in the setting of barotrauma.