History: male involved in high speed motor vehicle accident with chest pain.
This is a good example of a ductus diverticulum, or ductus bump. A ductus diverticulum is a focal smooth outpouching of the aortic wall at the aortic isthmus where the obliterated ductus arteriosus (the ligamentum arteriosum) is attached to the aorta. The ductus diverticulum is a normal finding and is present in approximately 9% of adults on aortograms. It is a mimicker of post-traumatic pseudoaneurysms which classically happen in high speed motor vehicle accidents. The differential diagnosis for this appearance includes a ductus diverticulum, a psuedoaneurysm, ulcerated atherosclerotic plaque, a diverticulum of Kommerell, and a true atherosclerotic aneurysm.
An excellent article explaining aortic wall abnormalities can be found here.
Thanks to Justin Tan, M.D. for this great example of a ductus diverticulum.