Ground-glass opacity (GGO) describes a finding on high-resolution computed tomography (HRCT) of the lungs in which there is hazy increased attenuation of the lung, with preservation of bronchial and vascular margins. This should not be confused with consolidation in which bronchovascular margins are obscured. The GGO is caused by partial filling of air space, interstitial thickening, partial collapse of alveoli, normal expiration, or increased capillary blood volume. Because GGO can represent either interstitial or alveolar processes, beyond the resolution of HRCT technique, the complete differential diagnosis is long.

Differential Diagnosis of Ground-Glass Opacity