Scientific Session 13 — Chest ImagingWednesday, May 3, 2017
2382. Single Center Review of Our Experience of Minimal Aortic Injury Using CT Angiography
Goodman W*, Parker M, Powell T, Edelstein M, Khangura R. Virginia Commonwealth University, Richmond, VA
Address correspondence to W. Goodman (email@example.com)
Objective: MDCT provides exquisite spatial resolution of the aorta not previously seen. Consequently, subtle acute traumatic aortic injuries (ATAIs) are increasingly encountered. Minimal aorta injury (MAI) describes a subset of ATAI characterized by localized intimal tears or intramural hematoma without external contour changes. As opposed to contained posttraumatic pseudoaneurysms or full-thickness ATAI, most MAIs have more favorable outcomes if conservatively managed with short-term sequential CT angiography (CTA) and blood pressure control. We present various CTA appearances of MAI and the natural history of this ATAI subset at our institution.
Materials and Methods: After obtaining institutional review board approval, we retrospectively reviewed 8686 blunt trauma chest CTA examinations performed from July 2012 to August 2016. MAI was defined as localized intimal tear or tears < 1 cm or intramural hematoma without external wall changes. Thirty-one patients met these criteria. CTA was performed on one of three CT scanners: Definition Flash, AS+FasCare, or 64 Fast Care (all Siemens Healthcare). Patients received 80–150 mL of iohexol 300–350 mg I/mL injected via a minimum 18-gauge IV at 4.0 mL/s with a 30-mL normal saline chaser and triggering at a 150-HU threshold. Two-millimeter-wide images were reconstructed every 1.0 mm and reformatted in axial, coronal, sagittal, and sagittal oblique planes. After-hours examinations are preliminarily read by residents in their third to fifth postgraduate years, but all examinations are formally read by emergency or cardiothoracic imaging staff with results conveyed to the trauma team. MAIs were assessed with repeat CTA in 24–48 hours. Recommendations were made to reimage stable injuries in 7 days, 30 days, and 6 months. Unstable injuries were aggressively managed. Electronic health records were used to document imaging follow-up times, clinical management, and patient outcome.
Results: Twenty MAI patients were male (mean age, 43.4 years; range, 25–61 years); 11 were female (mean age, 52.1 years; range, 24–89 years). Mechanistic factors included motor vehicle crashes (n = 20), motorcycle crashes (n = 5), driver (n = 18), passenger (n = 3), rollover (n = 6), ejection (n = 3), restrained (n = 8), unrestrained (n = 12), and other (n = 6). Conservative management included antihypertensives, anticoagulants, or both. Mean time to follow-up CTA was 3.26 days (range, 6 hours–13 days). One patient died before repeat imaging and another was lost to follow-up. On sequential imaging 29 patients showed stable or healed MAI including one patient with multifocal MAI with follow-up CTA at 1, 3, and 13 days after initial injury. No MAI injuries progressed. Three patients had died at the time of this review; two from nonsurvivable acute neurologic trauma and one from chronic neurologic injury. The mean time of clinical follow-up was 6 weeks (range, 0.6–20 weeks).
Conclusion: Our series mirrors results and findings reported elsewhere regarding imaging characteristics and short-term natural history of MAI. Although often clinically occult, MAI is a distinct pattern of ATAI. Given the favorable outcome with conservative management, radiologists must know how to differentiate MAI from other subtypes of ATAI mandating more aggressive management.