CT films show cords and shadows in the lungs, suggesting that the patient has suffered from chronic infectious lung diseases in the past, especially bronchial infectious diseases. Of course, long-term smoking and dust exposure, such as masons, coal mines, chefs, barbers, tailors, chemical industry, etc., engaged in the above industries long-term inhalation of dust and accept foreign body stimulation, easy to lead to chronic inflammatory changes in the bronchial tube, the formation of fibrous cords, CT is easy to find this change. Patients without clinical symptoms, such as coughing, coughing up sputum, chest tightness, shortness of breath, etc., do not need special treatment. Patients who smoke need to be given smoking cessation, and patients who are exposed to dust are advised to avoid dust. Because long-term, repeated episodes, exposure to dust is likely to lead to chronic cough, to bring some impact on lung function. Cord shadows do not belong to cancer changes, if there is no clinical symptoms do not need special treatment, only need to carry out imaging dynamic review.