▶ CT angiography demonstrates two aortic arches: one arch (white arrow in Fig. 67.4a) is right of the trachea at the level of the manubrium and a second one is left of the trachea. Note the esophageal thickening at the same level (black arrow in Fig. 67.4a). The left arch is smaller and more inferior (Fig. 67.4b).
▶ Thick maximum-intensity projection shows the ring created by the two arches on one image (Fig. 67.2). Volume-rendered CT nicely illustrates each arch giving rise to ipsilateral common carotid and subclavian arteries (Fig. 67.3).
▶ Differential diagnosis consists of aortic arch anomalies and mainly includes double aortic arch, left aortic arch with aberrant right subclavian artery, and right aortic arch with aberrant left subclavian artery.
▶ Aortic arch anomalies can form vascular rings that cause tracheoesophageal compression. Double aortic arch is the most common vascular ring to cause symptoms. Most patients are asymptomatic, but if symptomatic, they present with dysphagia, stridor, and recurrent infections.
▶ In double aortic arch two arches are present; with the right-sided arch usually larger and more superior than the left-sided arch. Each arch gives rise to its ipsilateral subclavian and carotid arteries.
▶ The descending aorta is usually left-sided.
▶ The distal left-sided arch is occasionally atretic, resulting in a fibrous cord. This cord is usually not directly seen on CT or MR. Because it creates a tight ring, secondary signs, especially tracheal compression, clue the reader to its presence.
▶ The longstanding extrinsic compression of the central airways by the vascular ring can cause tracheobronchomalacia that may persist after surgical repair.
▶ Double aortic arch is not associated with an increased incidence of congenital heart disease.
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Türkvatan A, Büyükbayraktar FG, Olçer T, et al. Congenital anomalies of the aortic arch: evaluation with the use of multidetector computed tomography. Korean J Radiol. 2009 Mar-Apr;10(2):176-184.Find this resource: