Left mediastinal width and mediastinal width ratio are better radiographic criteria than general mediastinal width for predicting blunt aortic injury.

BACKGROUND

General mediastinal width, left mediastinal width, and mediastinal width ratio were compared as radiographic predictors of aortic injury.

METHODS

A retrospective study investigated the chest radiographs of 51 patients admitted to a level 1 trauma center during a 6-year period for a thorough survey of aortic injury. Mediastinal width (MW >/= 8 cm), left mediastinal width (LMW >/= 6 cm), mediastinal width ratio (MWR >/= 0.60), and a combination of LMW and MWR were compared as predictors of aortic injury. The cutoff points were predetermined by receiver-operator-curve to accommodate 100% sensitivity for each criterion.

RESULTS

Of the 51 patients, 21 had aortic injuries and 30 had normal imaging studies. All criteria had 100% negative predictive value. The specificities and positive predictive values, respectively, were 13.3% and 44.7% (MW), 40.0% and 53.8% (LMW), 43.3% and 55.3% (MWR), and 66.7% and 67.7% (combined LMW and MWR). The positive likelihood ratio of aortic injury was 3.00 when LMW was 6 cm or more and MWR was 0.60 or more.

CONCLUSIONS

Both an LMW of 6 cm or more and an MWR of 0.60 or more are better radiographic criteria than an MW of 8 cm or more for predicting blunt aortic injury. Trauma patients with positive test results based on the combined LMW and MWR criteria should proceed immediately to aortography or helical computed tomography.