Archived case 202 · May 5-May 12, 2016
45 y/o male MVC. Assess for acute traumatic aortic injury
Do you see any subtle signs of trauma to the aorta?
Contrast enhanced CT images of the aorta reveal a small mural irregularity along the medial surface of the proximal descending portion. This area has somewhat of a tubular shape which appears to taper down as it extends outward. There is no surrounding inflammatory stranding or periaortic fluid. No dissection flap is identified. Answer Diagnosis: Branch vessel (right 3rd intercostal) infundibulum mimicking acute traumatic aortic injury.
Branch vessel (right 3rd intercostal) infundibulum mimicking acute traumatic aortic injury
Discussion: Acute traumatic aortic injury (ATAI) is a life threatening and often a life-ending event. It can result from either blunt or penetrating trauma: blunt trauma is more common and is typically a result of a motor vehicle collision or crush injury while gunshot or stab wounds can result in penetration injury.
Approximately 80% of patients with ATAI die at the scene of the trauma. In those who make it to hospital, clinical diagnosis is difficult. The signs and symptoms are non-specific and distracting injuries are often present. Clinical suspicion is usually based on mechanism and severity of the injury, the hemodynamic status of the patient and/or the presence of related injuries. The diagnosis ultimately relies on appropriate imaging.
Approximately 90% of ATAI occurs at the aortic isthmus, located between the left subclavian artery origin and the ligamentum arteriosum. Direct signs of ATAI include intraluminal filling defects, mural irregularity, pseudoaneurysm, and active extravasation.
Several entities can mimic ATAI and include a ductus diverticulum, noncalcified atherosclerotic plaque and, as in our case, a branch vessel infundibulum. Any of these may occur near the aortic isthmus and can be a challenging diagnosis in the setting of trauma.
The classic location for an infundibulum mimicking ATAI is the origin of the right third intercostal artery. They are typically smooth and conically shaped. If the vessel can be tracked into the intercostal space, the diagnosis is confirmed. Pseudoaneurysms or mural injuries are often irregularly shaped with sharp angles and may have surrounding fluid or stranding, both of which suggest an acute injury.
Additional reading:
1. “Lumps” and “Bumps” That Mimic Acute Aortic and Brachiocephalic Vessel Injury. RG Fisher et al. Radiographics 1997; 17:825-834
2. Acute Traumatic Aortic Injury: Imaging Evaluation and Management. SD Steenburg et al. Radiology September 2008 Vol 248, Issue 3
Original case written by its authors at Virginia Commonwealth University and published at this address as part of a weekly teaching collection. Reproduced here as an archive.