The differential diagnosis of the many causes of GGO includes pulmonary edema, infections (including severe acute respiratory syndrome coronavirus 2,[2] cytomegalovirus and Pneumocystis jirovecii pneumonia), various noninfectious interstitial lung diseases (such as hypersensitivity pneumonitis, Hamman-Rich syndrome), diffuse alveolar hemorrhage, cryptogenic organizing pneumonia, and pulmonary contusion.[3]