Coloured 3D computed tomography (CT) scan of the heart of a child with a right aortic arch (RAA) anomaly. This is a rare congenital (present at birth) defect, where the arch of the body's main artery, the aorta, tracks to the right of the windpipe (trachea). An RAA is often harmless, but can cause blood vessels to contract around the trachea and oesophagus (gullet) causing breathing and swallowing difficulties.