A ground glass shadow refers specifically to the imaging of both lungs on CT, indicating that it is a mild diffuse shadow. In general, this symptom is seen mainly in inflammatory and non-infectious inflammatory diseases of the lungs. Infectious inflammation is commonly seen in general viral, bacterial, and Mycobacterium tuberculosis infections, as well as in allergic pneumonia, such as eosinophilic pneumonia and alveolar protein deposition. Also common in interstitial lung diseases, such as idiopathic interstitial pulmonary fibrosis, and more malignant infectious diseases, such as neocoronavirus pneumonia and atypical pneumonia, can also present with such shadows.