Tiruvarur medical centre, No 5, Javulikara street, Tiruvarur, Tamil Nadu-610001, India.

Images 2, 3 and videos 1, 2: The images and videos show abnormal three-vessel trachea view - aortic arch on the right side of the trachea and ductus arteriosus on the left side forming a U-shaped loop around the trachea.

Definition

Right aortic arch is defined as the aortic arch that crosses the right bronchus instead of the left one. In a case of the right aortic arch the ductus arteriosus passes either to the right or to the left of trachea to join the aortic arch.

Prenatal sonographic findings

Four chamber view of the heart:  descending thoracic aorta is more centrally in front of the spine; Three-vessel-trachea view: transverse aortic arch passes by the right side of trachea while pulmonary artery and ductus arteriosus are to the left of the trachea forming a U-loop around the trachea [U sign ] [1, 2]. In some cases, ductus arteriosus also passes on the right side of the trachea making a V-configuration with the right sided aortic arch.

Associated abnormalities

Trisomy 21 and 22q11 microdeletion should be ruled out in cases of the right aortic arch [2].

Prognosis

Right aortic arch with left ductus arteriosus may cause tracheal compression on rare occasions.

References

1. Achiron R, Rotstein Z, Heggesh J, et al. Anomalies of the fetal aortic arch: a novel sonographic approach to in-utero diagnosis. Ultrasound Obstet Gynecol 2002; 20:553–557.

2. Alfred Abuhamad Rabih Chaoui ,A practical guide to Fetal Echocardiography,Normal and Abnormal Hearts,Second edition 2010