Angiographic evaluation of the ductus diverticulum.

The aortic isthmus in adults has a variable appearance on thoracic aortograms. Its configuration may show a concavity, a straightening or slight convexity, or a discrete focal bulge. The latter finding represents a ductus diverticulum and, in review of 103 aortograms, was found present in 9% of patients. At times a prominent ductus diverticulum may resemble, and be mistaken for, a traumatic pseudoaneurysm of the aortic isthmus. A traumatic pseudoaneurysm may be distinguished from a ductus diverticulum on aortography by demonstration of an intimal flap and/or delayed clearance of contrast material on subtracted films. However, a ductus diverticulum will exhibit neither of these features.