This patient is a young adult with chronic cough and some wheeze. This plain film shows some patchy, partly cystic shadowing in the right upper zone. There are subtle changes in the mediastinum- the lower trachea is not clearly seen. What do you think of the left upper mediastinum?
A coronal reconstruction of a high resolution CT shows bronchiectasis in the right upper zone, and an oddly positioned right upper lobe bronchus.
The 3D reconstruction of the central airways shows an anomalous right upper lobe bronchus (pre-eparterial bronchus, or bronchus suis). Below this there is severe stenosis of the trachea down to the carina.
The axial cut through this area shows a left pulmonary artery sling. The abberant left pulmonary artery arises from the base of the right and passes between the trachea and oesophagus to the left lung. This condition usually causes pressure on the trachea or left main bronchus, and often presents with stridor in the neonatal period.
As for the left upper mediastinum, it did look straight on the plain film and this coronal recon shows an incidental persistent left superior vena cava.