Right Sided Aortic Arch with Type C Aortic Arch Interruption: CT Angiography Findings

A 4-year old boy with a history of poor feeding, dyspnea and irritability while feeding that started since infancy, was referred to our center. Long-term examination of the disorder was started by echocardiography since he was one-month old and was performed when he was 2 years old. Although in all those evaluations, right sided aortic arch (RSAA) and increased right ventricle (RV) and pulmonary artery (PA) pressures were noticed, the definite diagnosis was not reached at that occasion. The patient was referred to our radiographic center and preceeded to undergo CT angiography with multislice spiral thin section scans plus maximum intensity projection (MIP), multiplanar reconstruction (MPR) and volume rendering techniques. The computed tomography (CT) angiographic findings revealed type C aortic arch interruption with right sided aortic arch which is a very rare condition and only one similar case has been previously reported in the literature. Interestingly, almost all types of right sided aortic arch interruptions reported so far were of type B. The reason why our case is type C could be explained from an embryologic point of view. Explanation of this case could be helpful and attractive since echocardiographic and angiographic findings were not definitive enough for final diagnosis of this case. The symptoms intensified after repairing the patient's ventricular septal defect (VSD); however, definite diagnosis was obtained by CT angiography. What makes this case report more important is that the authors believe that diagnostic methods in developed countries are able to diagnose this congenital heart disease sooner in neonatal or even in prenatal periods, resulting in a lower incidence of presentation of similar cases in childhood.