Tracheobronchography in the evaluation of anomalous left pulmonary artery.

In three patients the diagnosis of an anomalous left pulmonary artery was confirmed when tracheobronchography demonstrated a discrete extrinsic impression on the proximal right bronchus. The diagnosis was unsuspected clinically in one patient with a hyperlucent left lung on conventional chest radiographs. In the other two patients there was a suspicion of a pulmonary sling, but findings on plain chest or airway radiographs were atypical. The tracheobronchogram can be a valuable procedure for diagnosing a pulmonary sling, detecting additional developmental anomalies of the bronchi, and predicting the post-operative clinical course.