From the Guidelines
An air bronchogram is a radiographic sign where air-filled bronchi are made visible by the opacification of surrounding alveoli, typically in the context of pulmonary consolidation, as seen in conditions like organising pneumonia [ 1 ].
Characteristics of Air Bronchogram
- It is characterized by the visualization of air-filled bronchi against a background of opaque alveoli on chest radiographs or computed tomography scans.
- This phenomenon occurs when alveoli are filled with fluid, exudate, or other material, allowing the air-filled bronchi to stand out.
- The presence of an air bronchogram is often indicative of conditions such as pneumonia, pulmonary edema, or acute respiratory distress syndrome.
Clinical Significance
- The air bronchogram sign may guide diagnostic and therapeutic approaches, including the administration of antibiotics or supportive care measures like oxygen therapy and mechanical ventilation.
- In the context of organising pneumonia, air bronchograms are typically seen in subpleural locations and may appear migratory on serial imaging [ 1 ].
- Air bronchograms are an important radiographic feature that can aid in the diagnosis and management of various pulmonary conditions, highlighting the need for careful interpretation of chest imaging studies.
From the Research
Definition of Air Bronchogram
- An air bronchogram is a radiologic sign that refers to the appearance of air-filled bronchi made visible by the opacification of surrounding alveoli 2, 3, 4.
- It is typically seen in cases of alveolar consolidation, such as pneumonia or atelectasis, where the air-filled bronchi stand out against the opaque lung tissue 2, 3.
Types of Air Bronchograms
- Proximal air bronchograms: air is visible only to the level of the main bronchus, bronchus intermedius, or lobar bronchi 3.
- Intermediate air bronchograms: air is visible down to the segmental bronchi 3.
- Distal air bronchograms: air is visible down to the subsegmental bronchi or beyond 3.
- Dynamic air bronchograms: a sign of pneumonia, characterized by a dynamic pattern of air bronchograms on lung ultrasound 2.
- Static air bronchograms: more commonly seen in resorptive atelectasis, but can also be present in pneumonia 2.
Clinical Significance
- The presence of an air bronchogram can help distinguish between different types of lung diseases, such as pneumonia and atelectasis 2, 3.
- The type and location of the air bronchogram can provide information about the extent and nature of the lung disease 3.
- The air bronchogram can also be used to guide treatment, such as the need for fibreoptic bronchoscopy or chest physiotherapy 3.