Radiographic manifestations of congenital anomalies affecting the airway

Abstract

Congenital anomalies of the airway are generally uncommon, but a vast array of possibilities exists. Some present life-threatening emergencies at birth, and others go undiagnosed for years. Clinical symptoms are often nonspecific, and radiographic evaluation is frequently requested to localize and characterize the lesion before endoscopy, surgery, or medical management. The most common intrinsic congenital anomalies causing airway compromise in infants include choanal atresia, mandibular hypoplasia, laryngomalacia, vocal cord paralysis, and congenital subglottic stenosis. The radiologist must be on the alert for unsuspected additional anomalies involving the airway, lungs, and esophagus, which occur with relative frequency. Numerous extrinsic congenital masses of the head, neck, and mediastinum may compromise the airway. Hemangiomas, lymphangiomas, and teratomas are more likely to be noted at birth, whereas branchial cleft cysts, thyroglossal duct anomalies, and dermoid cysts frequently present later. Mass location and radiographic characteristics usually allow accurate preoperative diagnosis. Intracranial involvement by nasal or nasopharyngeal masses, intrathoracic involvement by lower neck mass, and intraspinal involvement by posterior neck mass must always be sought for radiographically. Persistence of respiratory symptoms after removal of such masses is not uncommon because tracheal deformity and laxity may take months or years to resolve. Recent advances in cine CT and MR imaging promise to improve imaging of the airway in general and in the pediatric population in particular. Significant limitations in imaging of the pediatric larynx remain. As a result, endoscopy continues to be the primary diagnostic tool for airway anomalies of this region.