Hyperdense shadows in the lower lobes of both lungs are caused by diseases such as nodules, inflammation, hemorrhage, tuberculosis, and tumors. Normal lung tissue is blackish and hypodense, but when the gas in normal lung tissue is replaced by solid or liquid material due to a lesion, it appears whitish and dense. The lesions are commonly found in nodules, inflammation, tuberculosis and tumors, etc. If the lungs are infected, there will be high-density patchy shadows, and there will be cough, sputum, fever and other symptoms. If the high-density shadow occurs in the dorsal segment of the lower lobe, it suggests that there is a possibility of tuberculosis, and sputum tuberculin test is often done to make diagnosis, and if the high-density shadow is in the form of a mass, then it is possible to be lung cancer, and the gold standard is pathologic biopsy. The gold standard is pathological biopsy. It is recommended to consult a professional doctor in a regular hospital in time, and carry out relevant examination and targeted treatment.