The computed tomography mucous bronchogram sign

Abstract

Mucous secretions filling the bronchial tree may be identified on computed tomography (CT) as low-density, treelike branching structures within consolidated or collapsed lungs similar to air bronchograms. These mucous bronchograms may occur from mucoid impaction of the bronchi distal to an obstructing lesion of the bronchus, most notably bronchogenic carcinoma, and from conditions that cause impaired mucociliary transport. In most cases, thin-section CT (5 mm) will demonstrate the presence or absence of an obstructing tumor involving the bronchus and will allow a correct assessment as to the cause of the mucous bronchograms; however, on occasion mucus within the central bronchi may result in a false-positive CT diagnosis of obstructing tumor. The demonstration of mucous bronchograms within a thoracic mass indicates that the mass is consolidated or collapsed pulmonary tissue and allows distinction from pleural disease.