CT assessment of tracheobronchial anomaly in left pulmonary artery sling

The left pulmonary artery sling (LPAS) is a rare vascular anomaly where the left pulmonary artery arises from the right pulmonary artery, passes over the right bronchus, and goes posteriorly between the trachea and esophagus. The LPAS is frequently associated with cardiac and non-cardiac defects including tracheobronchial abnormalities.

To evaluate the utility of multislice CT (MSCT) and helical CT (HCT) in diagnosing and defining the tracheobronchial anomaly and anatomic relationships between the trachea and aberrant left pulmonary artery.

MSCT or HCT was performed in 27 children to determine the tracheobronchial anatomy and identify tracheobronchial stenosis. Eighteen children underwent surgery.

According to the Wells classification of LPAS, which includes two main types and two subtypes, there were eight cases of type 1A, five cases of type 1B, six cases of type 2A and eight cases of type 2B in this group. Twenty-four of the 27 children had substantial tracheobronchial stenosis. Four died before surgery; the 18 had reanastomosis of the left pulmonary artery. Five children also had tracheoplasty; three died after surgery.

CT, especially MSCT, is an ideal modality for simultaneously identifying aberrant left pulmonary artery and any associated tracheobronchial anomaly. The Wells classification is useful for operative planning.