CT lung examination is the most important method to diagnose pulmonary fibrosis and interstitial lung disease. The respiratory physician will make a reasonable diagnosis based on the CT lung manifestations, combined with medical history, physical examination, pulmonary function tests, and other laboratory results. For the diagnosis of pulmonary fibrosis and interstitial lung disease, the best CT examination of the lungs is high-resolution CT, which is generally available in large hospitals. High-resolution CT can visualize the details of lesions, especially for some common imaging manifestations of interstitial lung disease, such as honeycomb lung, ground glass shadow, and fine nodular shadow, which can be shown more clearly. An experienced respiratory physician can basically make a general judgment on the diagnosis based on high-resolution CT of the lung, combined with clinical manifestations. Although they are all pulmonary fibrosis, there are differences in the CT presentation of different types of pulmonary fibrosis, or different causes of pulmonary fibrosis. These differences are not always noticed by radiologists and often require a differential diagnosis after seeing the patient by a respiratory physician. It is important to emphasize that in the case of pulmonary fibrosis and interstitial lung disease, the CT findings reported by the radiologist are not necessarily the diagnosis of the disease. That is, radiologists will give a specific description of the abnormalities they see based on the CT presentation and will give an imaging diagnosis that is different from the clinical diagnosis of the disease. For example, sometimes a radiology report will say “interstitial lung changes”, a term that is very broad and does not necessarily indicate interstitial lung disease, but perhaps a lung infection or other problem. This requires a comprehensive assessment of the CT findings by the respiratory physician after seeing the patient. I have personally had the experience of patients who come in with similar CT reports, and after looking at the CT films and asking if there are any symptoms or abnormalities on examination, it is not difficult to determine that some of them are not pulmonary fibrosis or interstitial lung disease. In conclusion, pulmonary fibrosis and interstitial lung disease are collective terms for many diseases, and the diagnosis is more complicated. High-resolution CT of the lungs is an indispensable test for the diagnosis of these diseases, but CT results alone do not allow a correct diagnosis to be made. A definitive diagnosis of pulmonary fibrosis and interstitial lung disease also requires a respiratory physician to do so after integrating the clinical manifestations and other necessary test results.