Value of plain chest film in predicting traumatic aortic rupture.

Plain chest film performed after blunt chest trauma showed blurring of the left pulmonary hilum in 53% of cases of traumatic aortic rupture (Group A, n = 15), and in no cases with negative aortography (Group B, n = 10). This sign can be explained by diffusion of mediastinal hemorrhage through the peri-bronchovascular connective tissue; the close relationship between aortic isthmus, the side of most frequent rupture, and the left pulmonary hilum is the anatomical basis for this asymmetrical finding. Review of all radiological alterations of the plain chest film shows a statistically significant difference between groups A and B only for mediastinal widening and aortic knob alterations (p less than 0.05). A combination of some findings due to aortic injury (mediastinal widening, aortic knob alterations, shift of trachea and left main bronchus, left apical cap, left hilar blurring, obscuring of descending aorta) was typical of aortic rupture when four or more signs were found (33%); these findings were absent only in patients with negative aortogram (8%). In the remaining cases (60%), the plain chest film showed two or three of these signs in both groups, making it impossible to differentiate between patients with and without aortic injury.