Pulmonary Sling

Etiology: left pulmonary artery arises from posterior right pulmonary artery
Imaging: left pulmonary artery traverses mediastinum from right to left coursing between trachea and esophagus, this can lead to fluid + air trapping of lung
UGI: posterior indentation on trachea + anterior indentation on esophagus
Clinical: can have associated right lung abnormalities (atelectasis / hypoplasia) and ring sling complex – tracheal ring cartilage + tracheal stenosis

Radiology Cases of Pulmonary Sling

UGI of pulmonary sling — AP (above) and lateral (below) images from an upper GI exam shows right sided and anterior indentations on the esophagus.

Angiogram of pulmonary sling — AP image from a pulmonary angiogram shows the left pulmonary artery arising from the right pulmonary artery.

CT of pulmonary sling causing tracheal stenosis — Axial CT with contrast of the chest shows the left pulmonary artery arising from the right pulmonary artery and then coursing posterior to the trachea and anterior to the esophagus, causing focal narrowing of the trachea at this level.