Imaging description

A six-month-old girl was evaluated by her primary care physician for noisy breathing while feeding and failure to thrive. He ordered an upper gastrointestinal study which was normal except for an anterior impression on the mid esophagus (Fig. 24.1a). A chest radiograph (Fig. 24.1b) demonstrated cardiomediastinal shift to the right with a slightly small volume right lung; the lower trachea was poorly visualized. A CT angiogram was then obtained to evaluate for vascular abnormality or mediastinal mass. On the CTA a left pulmonary artery sling (LPAS) was identified as well as a right mid tracheal diverticulum and long segment lower tracheal stenosis with a rounded configuration suggesting complete cartilaginous rings (Fig. 24.1c–e).

Importance

A LPAS occurs when the left postbranchial pulmonary vessels connect with the right instead of the left sixth branchial arch with the aberrant vessel taking a course from right to left between the trachea and esophagus to reach the left hilum (Fig. 24.1c). This course tends to produce an anterior vascular impression on the esophagus (Fig. 24.1a), separating it from the trachea, whereas the anomalous vessels in vascular rings pass posterior to both trachea and esophagus.