Compensatory emphysema is a normal physiological process, because the total area of the lung is reduced after partial removal of the lung, and in order to ensure the body’s oxygen needs, the other side of the lung will be compensated for the expansion, thus forming compensatory emphysema, which is generally asymptomatic. Generally, compensated emphysema is asymptomatic. However, if the lung loses this function, it is considered non-compensated emphysema. How is compensated emphysema diagnosed? Compensation is beneficial to the organism and can compensate for the lost function of the organ, but sometimes compensation can bring some unfavorable side effects to the organism, such as pulmonary atrophy or bronchial asthma, when compensatory emphysema can occur, when the alveolar cavity of the emphysema is over-inflated, the capillaries of the alveolar septum are compressed, the resistance to blood flow in the pulmonary circulation increases, and the burden on the right heart increases. In severe cases, it can also lead to pulmonary heart disease. Lower lobe atelectasis is a triangular dense shadow with the tip of the lower lung field on the upper side and the base on the lower side, and the hilum is shifted downward, sometimes the lower part of the hilum disappears. There is compensatory emphysema in the upper and middle lobes. Lower lobe opacification of the right lung is more clearly shown than the left because of the overlapping cardiac shadow on the left side, but it can be shown on oblique or overexposure films. In lateral position, the lower lobe opacification shows oblique fissure shifted posteriorly and inferiorly with high density in the lower lobe. Thickening of the two lower lung textures is seen on X-ray in patients with chronic bronchitis, which is a chronic non-specific inflammation of the trachea, bronchial mucosa and surrounding tissues due to infectious or non-infectious factors. Some patients have a history of acute respiratory infections such as acute bronchitis, influenza or pneumonia before the onset of symptoms, which develop into this disease due to prolonged treatment. The main symptoms are chronic cough, sputum and shortness of breath or wheezing. The symptoms are initially mild, but as the disease progresses, acute attacks become more frequent and more severe due to repeated respiratory infections, especially in winter. Hyperinflation of the lungs is commonly referred to as emphysema. Emphysema is a pathological condition in which the airways of the distal end bronchioles (respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli) become less elastic, hyperinflated, inflated and have increased lung volume or are accompanied by destruction of the airway walls. There are several types of emphysema according to their pathogenesis: senile emphysema, compensatory emphysema, interstitial emphysema, focal emphysema, paracentral emphysema, and obstructive emphysema. Pulmonary diffusion dysfunction, i.e. the size of the diffusion volume, depends on the difference in partial pressure of the gas on both sides of the membrane, diffusion area, distance, time, molecular weight of the gas and its solubility in the diffusion medium. Reduced diffusion function can be caused by emphysema and other lung tissue lesions, diffuse interstitial lung fibrosis, and other diseases. When pulmonary pathology produces diffusion dysfunction clinically, it is often accompanied by a significant ventilation/blood flow dysfunction, the consequences of which all lead to hypoxia.