Case report: aneurysm of an aberrant right subclavian artery diagnosed with MR imaging.

An aberrant right subclavian artery (ARSCA), also known as arteria lusoria, is the most common congenital anomaly of the aortic arch, with a reported prevalence ranging from 0.4 to 2%. The ARSCA arises as the last branch of the aortic arch and crosses the mediastinum from left to right indenting the oesophagus posteriorly. Aneurysms of this aberrant vessel, whether or not arising from a Kommerell's diverticulum, are rare. A 79-year-old woman is presented, in whom a partly thrombosed aneurysm of an ARSCA was diagnosed with magnetic resonance (MR) imaging.