Normal chest CT image can see the patient’s two sides of the thorax is symmetrical, rib alignment is normal, both sides of the lungs of the lung texture alignment is normal, no obvious abnormal density shadow, the mediastinum position, size is normal, both sides of the rib-diaphragm angle is smooth and sharp, there is no other abnormal density shadow. Normal chest image can see whether the patient has lung disease, pleural disease, and also can probably indicate whether there is a problem in the mediastinum. Chest CT is the imaging method of choice for lung disease because of its high density resolution, so most lung diseases can be detected by chest CT.