Multiple hyperdense foci in the upper lobe of the left lung may be associated with lung inflammation, tuberculosis, lung tumors, and the immune system. High density shadows in the upper lobe of the left lung are mostly due to inflammation of the lungs, including acute and chronic inflammation. If the inflammation is acute, the patient will have more obvious respiratory symptoms, such as fever, cough and sputum. If the inflammation is chronic, the fever may not be as pronounced. In tuberculosis, the upper lobe of the left lung will have a high density shadow, and calcified foci can be seen on CT. At this time, it is necessary to distinguish between the infected stage and the stable stage, and to determine whether and how to treat according to the different stages of the onset of tuberculosis. Elderly patients with high density shadows in the upper lobe of the left lung may be related to lung tumors. Enhanced CT examination of the chest is needed to assist in the diagnosis, and puncture biopsy of the high-density shadow in the upper lobe of the left lung is needed to clarify the diagnosis if necessary. Some immune system diseases, such as rheumatic pneumonia and connective tissue disease, may cause inflammatory reaction and edema in lung tissue, which manifests as multiple patchy high-density foci. If you find multiple high-density foci in the upper lobe of the left lung, you should consult a doctor in time and take treatment under the doctor’s guidance. Pay attention to personal hygiene, maintain a regular routine, quit smoking and drinking, and avoid overwork.