In patients with novel coronavirus pneumonia, the lung CT mainly shows multiple small patchy shadows and interstitial changes in the early stage, which are obvious in the outer lung bands. Because of the high number of interstitial areas in the outer zone, they develop into multiple ground glass and infiltrative shadows in both lungs, and a small number of solid lung changes can occur, with less pleural effusion. Depending on the severity of the patient, novel coronavirus pneumonia is classified into mild, common, severe or critical forms. The corresponding pulmonary CT manifestations are as follows: 1) in mild patients, CT generally has no pneumonia manifestations; 2) in general type patients, there are generally bilateral subpleural patchy images, and some of them can progress to solid lesions; 3) in severe patients, the extent of lesions progresses faster and more widely, with solid lesions predominating and bronchial images appearing; 4) in critically ill patients, CT can show diffuse changes in both lungs, or even complete solid lesions. Critical illness does not lie in the extent of lesions, its main thing is that there will be diffuse solid changes in both lungs in the short term or further aggravation at a faster rate, which is a typical symptom of novel coronavirus pneumonia. Content source: Dr. Yurei