Imaging description

In double aortic arch, the ascending aorta divides into left and right arches (Figure 48.1). Usually, both arches are patent; in a minority of cases, a portion of the smaller arch is atretic. The left arch is generally in a normal position relative to mediastinal structures, passing anterior and to the left of the trachea and esophagus. The right arch usually extends further cephalad than the left arch, and it passes to the right and posterior to the trachea and esophagus. In 70–80% of cases the right arch is larger [1–3]. A subclavian and a common carotid artery arise from each arch. The two arches combine in the upper chest to form the descending aorta, which usually lies in a normal position to the left of the spine [1–4].

Importance

Double aortic arch is the most common complete vascular ring. The two arches encircle the trachea and esophagus, which can result in tracheal or esophageal narrowing. Associated congenital intracardiac defects are rare [1–4].