Ground-Glass Opacity and Black Bronchus Sign

Abstract

Ground-glass opacity (GGO) is a nonspecific finding which represents a hazy area of increased attenuation in the lung (↑) with preservation of bronchial and vascular margins. It may be caused by normal expiration, partial collapse of alveoli, increased capillary blood volume, partial filling of air spaces, or interstitial thickening. In patients with acute clinical symptoms, the presence of GGO reflects an active disease (e.g., pneumonia, edema, diffuse alveolar damage). In most patients with chronic symptoms, GGO also indicates active and potentially treatable stages of a long-lasting pathologic process (e.g., interstitial pneumonia, hypersensitivity pneumonitis, and sarcoidosis). GGO may also be found in patients with bronchoalveolar carcinoma that assumes dynamic control or morphological verification.

Ground-glass opacity (GGO) is a nonspecific finding which represents a hazy area of increased attenuation in the lung (↑) with preservation of bronchial and vascular margins. It may be caused by normal expiration, partial collapse of alveoli, increased capillary blood volume, partial filling of air spaces, or interstitial thickening. In patients with acute clinical symptoms, the presence of GGO reflects an active disease (e.g., pneumonia, edema, diffuse alveolar damage). In most patients with chronic symptoms, GGO also indicates active and potentially treatable stages of a long-lasting pathologic process (e.g., interstitial pneumonia, hypersensitivity pneumonitis, and sarcoidosis). GGO may also be found in patients with bronchoalveolar carcinoma that assumes dynamic control or morphological verification.

The bronchi filled with air are markedly seen against GGO unlike normal pulmonary tissue – the “black bronchus” sign (∆).