Air bronchogram – Mechanism, Causes
- Air bronchogram refers to the visualisation of air filled bronchus when the surrounding alveoli are opacified
Causes:
- Pulmonary consolidation
- Pulmonary oedema
- ARDS
- Hyaline membrane disease
- Alveolar cell carcinoma
- Alveolar proteinosis
- Sarcoidosis
- Lymphoma
Mechanism:
- Normally the lung fields are radioluscent and the bronchi are not separately visualised
- But in the above mentioned conditions, there is opacification of the alveoli due to various reasons (eg: fluid accumulation is pulmonary oedema)
- Due to this reason, the bronchi stands out as radioluscent in contrast to the adjacent alveoli that are radio opaque
- Visualisation of air bronchogram helps in identifying the underlying pathology
