Lateral image from an esophagram (above left) shows a posterior indentation on the esophagus which was persistent. Coronal CT with contrast of the chest (above right) with 3D reconstructions (below) show a right-sided aortic arch with an aberrant left subclavian artery that originated from a Kommerell diverticulum and that courses behind the esophagus. The ductus arteriosus was noted to extend from the Kommerell diverticulum and completed the vascular ring.