CT shows cords and nodular hyperdense shadows in the upper lobe of the left lung, which are usually not serious and mostly benign, and may be due to chronic inflammation and old tuberculous lesions. 1. Chronic inflammation: the cords and nodular hyperdense shadows seen in the left upper lung are generally suggestive of old lesions in the lungs, and in most cases are due to chronic inflammation. Inflammation persists, and lung tissues continue to be destroyed and repaired, resulting in the formation of high-density shadows, which are generally not serious. When coughing, coughing sputum, fever, or high-density shadows become larger, more timely to the hospital, the application of azithromycin and other anti-infective treatment. 2. Old tuberculosis foci: Adults usually have old tuberculosis, mainly striated shadow in the upper lobe of the lung. If CT suggests focal hyperdense shadow, it usually means that the tuberculosis is in a quiescent state, so there is no need to worry too much. If accompanied by low-grade fever, night sweats and other manifestations, and at the same time the image suggests that the scope of high-density shadow is enlarged, then we need to pay attention to it, and apply anti-tuberculosis drugs such as rifampicin under the guidance of the doctor. Therefore, if CT shows striated and nodular hyperdense shadows in the upper lobe of the left lung, it is usually not serious and may be chronic inflammation. In a few cases, the high density shadow is caused by old tuberculosis. If low-grade fever and night sweats occur, it is recommended to consult a doctor in time, and puncture biopsy is needed to clarify the nature if necessary.