- False positive due to expiration / flexion
- Nasopharynx (tonsillar enlargement [adenoid, lingual, palatine], choanal atresia, juvenile nasopharangeal angiofibroma)
- Posterior oropharynx (micrognathia with posterior placement of tongue, macroglossia, epidermal inclusion cyst of tongue, thyroglossal duct cyst, ectopic thyroid)
- Larynx / Trachea (intrinsic to airway) [laryngomalacia, congenital cyst of airway, papilloma, tracheal granuloma, subglottic hemangioma, chronic airway foreign body]
- Neck (extrinsic to airway) [lymphatic malformation, hemangioma, lymphoma [Hodgkin, Non-Hodgkin], esophageal foreign body]
Approach to the differential diagnosis of chronic upper airway obstruction:
- Beware of false positive due to expiration / flexion
- Nasopharynx
- Tonsillar enlargement – make the tonsils part of your normal scan
- Choanal atresia – presents with hypoxia with feeding
- Juvenile nasopharangeal angiofibroma – presents with epistaxis
- Posterior oropharynx
- Micrognathia with posterior placement of tongue
- Macroglossia
- Inclusion cyst of tongue
- Thyroglossal duct cyst – midline neck cyst that moves with tongue protrusion + swallowing on US
- Ectopic thyroid – confirmation is via nuclear medicine scan
- Larynx / Trachea (intrinsic to airway)
- Laryngomalacia – can be diagnosed with airway fluoroscopy
- Congenital cyst of airway
- Papilloma – suspect with lesions that are multiple + associated with cystic chest lesions
- Granuloma – requires history of longstanding endotracheal intubation
- Hemangioma – concurrent skin hemangioma makes the diagnosis
- Chronic airway foreign body – 90% of airway foreign bodies are radiolucent
- Neck (extrinsic to airway)
- Lymphatic malformation – transpatial mass that is micro- or macrocystic and not very vascular
- Hemangioma – solid mass that is hypervascular
- Lymphoma – lymphadenopathy can surround, shift, compress trachea
- Esophageal foreign bodies can cause surrounding edema leading to tracheal narrowing
Pediatric Imaging 