The computed tomography mucous bronchogram sign

Area of Science:

• Radiology
• Pulmonary Medicine
• Medical Imaging

Background:

• Mucous secretions in the bronchial tree can appear as low-density, branching structures on computed tomography (CT), mimicking air bronchograms.
• These findings, termed mucous bronchograms, are often associated with mucoid impaction of bronchi, frequently caused by obstructing lesions like bronchogenic carcinoma or impaired mucociliary transport.

Purpose of the Study:

• To describe the CT findings of mucous bronchograms.
• To differentiate mucous bronchograms from other causes of bronchial abnormalities on CT.
• To assess the utility of thin-section CT in diagnosing the underlying cause of mucous bronchograms.

Main Methods:

• Review of CT scans demonstrating mucous bronchograms.
• Analysis of thin-section CT (5 mm) findings.
• Correlation with clinical and pathological data where available.

Main Results:

• Mucous bronchograms are treelike, low-density structures within consolidated or collapsed lung parenchyma.
• Thin-section CT is effective in identifying the presence or absence of an obstructing tumor.
• Mucous impaction and impaired mucociliary transport are common causes.
• Central bronchial mucus can occasionally lead to a false-positive diagnosis of an obstructing tumor.
• Mucous bronchograms within a thoracic mass indicate consolidated or collapsed lung tissue, distinguishing it from pleural disease.

Conclusions:

• Mucous bronchograms are a recognizable CT finding with specific differential diagnoses.
• Thin-section CT is crucial for accurate assessment and differentiation from obstructing tumors.
• Understanding mucous bronchograms aids in the diagnosis of various pulmonary conditions and mass characterization.