Imaging a boa constrictor--the incomplete double aortic arch syndrome.

Incomplete double aortic arch is a rare anomaly resulting from atresia rather than complete involution in the distal left arch resulting in a non-patent fibrous cord between the left arch and descending thoracic aorta. This anatomic anomaly may cause symptomatic vascular rings, leading to stridor, wheezing, or dysphagia, requiring surgical transection of the fibrous cord. Herein, we describe an asymptomatic 59 year-old man presenting for contrast-enhanced CT angiography to assess cardiac anatomy prior to radiofrequency ablation, who was incidentally found to have an incomplete double aortic arch with hypoplasia of the left arch segment and an aortic diverticulum. Recognition of this abnormality by imaging is important to inform both corrective surgery in symptomatic patients, as well as assist in the planning of percutaneous coronary and vascular interventions.