The patient was then scanned with dynamic contrast administration, with an oesophageal boogie in situ (to better delineate the oesophagus).
CTA of the chest obtained with a boogie (light-yellow cylinder) in oesophagus (trachea anterior to it not seen) demonstrates a mirror image aortic arch with aberrant left subclavian artery (order of vessel origin from the aortic arch: left CCA, right CCA, right subclavian, left subclavian) which passes behind the oesophagus creating an incomplete ring.