Double aortic arch has been classified as type 1 (both arches patent) and type 2 (one arch atretic). The atretic arch is almost invariably the left. Type 2 double arches may be subclassified according to the position of the atresia. Subtype 1 the atretic segment is between ductus arteriosus and descending aorta; subtype 2 it is between left subclavian artery and ductus arteriosus; subtype 3 it is between left common carotid artery and left subclavian artery; and subtype 4 the atresia is between ascending aorta and left common carotid artery. In subtype 3 it is common for the left subclavian artery to arise from a diverticulum. The diverticulum has the same embryologic origin as that originally described by Burckhard Kommerell, and may reasonably be referred to as a Kommerell’s diverticulum.

Double aortic arch is an important vascular ring anomaly, as the arches and atretic ligamentous cords surround and potentially compress the trachea and oesophagus. A clue as to the presence of double arch on barium swallow is the presence of focal oesophageal narrowing in both the AP and transverse directions.

Patient #1: MR images demonstrates a double aortic arch

A double aortic arch may be observed through multiple diagnostic techniques:

• MRI
• CT

Cardiology