Imaging studies in evaluating children with stridor.

Stridor is a symptom of upper airway obstruction and may result from congenital or acquired causes. The diagnosis is usually clinical. If further investigation is necessary for differential diagnosis, endoscopy is the method of choice in most cases. Imaging studies are complementary to endoscopy. They allow evaluation of laryngeal and tracheobronchial pathology and extrinsic airway compressions due to tumors or vascular malformations and define a lesion's location, extent, and characteristics. They are helpful in cases of diagnostic doubt and when endoscopy is unavailable. It is essential to understand the anatomy and pathophysiology of the respiratory tract and to be aware of the indications and limitations of complementary examinations for proper diagnosis. The different imaging modalities available to evaluate stridor in pediatrics are described, and their advantages are discussed.