CT evaluation of traumatic diaphragmatic injury: a large retrospective cohort study of blunt and penetrating trauma.

PURPOSE: To evaluate the diagnostic performance and interobserver agreement of CT signs for traumatic diaphragmatic injury (TDI) in a large surgically confirmed cohort, stratified by blunt and penetrating mechanisms.

METHODS

This retrospective study included 106 patients with surgically confirmed TDI (38 blunt, 68 penetrating) who underwent preoperative multidetector CT between 2010 and 2022 at a level 1 trauma center. A matched control group comprised 107 patients with surgically confirmed intact diaphragms. Two blinded radiologists independently reviewed randomized CT examinations, assessing predefined direct and indirect signs: diaphragm discontinuity, intrathoracic herniation, focal thickening, dependent viscera, collar sign, and trajectory of injury (penetrating only). Interobserver agreement was measured with kappa statistics, and logistic regression identified independent predictors of TDI.

RESULTS

In blunt trauma, diaphragm discontinuity and intrathoracic herniation were the most sensitive signs (65–77%). In penetrating trauma, the trajectory sign demonstrated the highest sensitivity (89–91%), followed by diaphragm discontinuity and focal thickening (39–61%). Radiologists’ overall impression yielded sensitivities of 76–82% for blunt and 82–87% for penetrating trauma. Interobserver agreement was substantial (κ = 0.61–0.80).

CONCLUSION

Diaphragm discontinuity and intrathoracic herniation are key predictors of blunt TDI, whereas trajectory and focal thickening are most predictive in penetrating trauma. Recognition of mechanism-specific CT predictors may improve timely diagnosis and reduce morbidity from delayed repair.