Aortic ductus diverticulum is a developmental outpouching of the thoracic aorta which may be mistaken for an acute aortic injury.
It is usually seen at the anteromedial aspect of the aorta at site of the aortic isthmus, where the ligamentum arteriosum attaches. It is also the site of the majority (~90%) of post-traumatic aortic injuries as the ligamentum arteriosum is one of the points to which the thoracic aorta is tethered; therefore, differentiation of ductus diverticulum from traumatic pseudoaneurysm is vitally important.
In contrast to an aortic pseudoaneurysm, which usually forms sharp margins with the aorta, ductus diverticulum usually appears as a smooth focal bulge with gentle obtuse angles with the aortic wall.
Ductus diverticula are divided into:
- smooth gentle shoulders
- 33% newborns
- 9% adults
- sharper with a shorter and steeper superior slope
- aortic pseudoaneurysm / aortic arch pseudoaneurysm
- minimal aortic injury
- aortic spindle - circumferential dilatation just distal to the isthmus
For differentiating features, see aortic pseudoaneursym versus ductus diverticulum.