Left pulmonary artery sling: Diagnosis and delineation of associated tracheobronchial anomalies with MR

Background. The left pulmonary artery sling anomaly (SLPA) has generated controversy about its diagnosis, imaging and management particularly with regard to associated tracheobronchial anomalies. Objective. To evaluate the role of MR imaging in defining airway and vascular relationships in SLPA. Materials and methods. Retrospective review of the imaging and clinical records of three children with SLPA who underwent MRI including three dimensional image reconstruction. MR was compared and correlated with other imaging methods: plain chest radiographs (3); bronchoscopy (3); barium esophagram (1); echocardiography (2); cineangiography (2). Results. MRI was vastly superior to other methods for clearly depicting airway and vascular anatomy and interrelationships. Good quality imaging and safe sedation was easily achieved in young infants. MR also provided accurate noninvasive evaluation of the reconstructed pulmonary artery and airway postoperatively. Conclusion. MR is capable of differentiating the two subtypes of SLPA. Specific delineation of vascular and airway anatomy and spatial relationships is essential for surgical management: reimplantation of LPA in type I and both LPA reimplantation and airway reconstruction in type II because of associated long segment airway stenosis.