MR imaging of the pediatric airway.

The mainstays of initial evaluation of the airway in infants and children are chest radiography and esophagography. Magnetic resonance (MR) imaging is frequently used next to diagnose specific abnormalities and obviates angiocardiography. MR imaging usually allows distinction between a double aortic arch and a right aortic arch with an aberrant left subclavian artery. In cases of pulmonary artery sling, MR imaging enables full evaluation of the vascular anatomy and may also demonstrate the tracheobronchial anomalies. MR imaging may aid in diagnosis of innominate artery compression syndrome by demonstrating the extent of the tracheal luminal narrowing, the tracheal configuration, the structure causing the compression, and the size of the thymus. Finally, MR imaging usually allows distinction of long-segment tracheal stenosis from tracheomalacia and is especially helpful in cases of isolated stenosis. Three-dimensional reconstructions are also useful in assessing relationships between vascular structures and the adjacent trachea.