Ground glass opacity

In radiology, ground glass opacity (GGO) is a nonspecific finding on computed tomography (CT) scans that indicates a partial filling of air spaces in the lungs by exudate or transudate, as well as interstitial thickening or partial collapse of lung alveoli.

The differential diagnosis of the many causes of GGO includes pulmonary edema, infections (including cytomegalovirus and Pneumocystis carinii pneumonia), various noninfectious interstitial lung diseases (such as hypersensitivity pneumonitis, Hamman-Rich syndrome), diffuse alveolar hemorrhage, and cryptogenic organizing pneumonia.

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