Indeterminate CT angiography in blunt thoracic trauma: is CT angiography enough?

The primary objective of our study was to determine whether catheter angiography is needed to exclude aortic and intrathoracic great vessel injury when CT angiography (CTA) findings are indeterminate (mediastinal hematoma without direct evidence of aortic or intrathoracic great vessel injury). The secondary objective was to devise a classification scheme for mediastinal hematomas.

This study is a retrospective analysis of patients presenting with blunt trauma over 4.5 years at a level 1 trauma center. Indeterminate CTA findings in patients with blunt injury were identified through a database search of imaging reports. CTA findings and final outcomes, including catheter angiography and clinicopathologic records, were reviewed independently by blinded observers.

One hundred seven patients (age range, 11-88 years) met the inclusion criteria. Seventy-two (age range, 15-88 years) had a reference standard of subsequent catheter angiography, and 35 subjects (age range, 11-87 years) did not undergo catheter angiography and therefore had a reference standard of clinicopathologic review. No subjects with isolated mediastinal hematoma on CTA had aortic or intrathoracic great vessel injury, for a positive predictive value of 0% (95% CI, 0-0.028). Using our proposed classification scheme, we found a direct correlation between the percentage of cases that underwent catheter angiography and hematoma severity.

When CTA is indeterminate in blunt thoracic trauma, conventional angiography is unlikely to show an aortic or intrathoracic great vessel injury and may be unnecessary. A grading system for mediastinal hematomas could help triage patients to conventional angiography when further imaging is desired.