The cause of consolidation shadow in the left upper lung field is inflammatory lesion in the lung, which is commonly seen in lobar pneumonia. The consolidation shadow in the left lung is found through imaging examinations such as X-ray chest radiography, CT, or MRI, revealing inflammatory lesions in the lung, which are typically characteristic of lobar pneumonia. This is mostly due to the infection of the lung by Streptococcus pneumoniae, causing inflammatory changes in the lung. The main lesions involve the lung segment and the lung lobe, presenting as consolidation, congestion, and edema of the lung, with a large amount of inflammatory secretions exudated. Clinically, other symptoms may accompany, such as sudden high fever that does not subside, chills, fear of cold, chest pain, chest tightness, cough, and coughing up large amounts of rusty sputum. Clinically, penicillin is the preferred antibiotic for treatment, which can completely cure the disease within one week, and the consolidation shadow in the lung will disappear. There are many causes of lung consolidation, and the liquid sources causing lung consolidation mainly include three types: ① excessive secretion of airway mucosal epithelium, mainly seen in infections caused by bacteria, viruses, and fungi; ② increased leakage of capillary serum, seen in pulmonary edema caused by elevated pulmonary venous pressure during left heart failure, with edema spreading gradually from the hilum to the periphery of the lung, presenting as a butterfly-shaped distribution; ③ aspiration of liquid, which can be caused by drowning or accidental aspiration into the lungs due to vomiting. Examination of Consolidation Shadow in the Left Upper Lung Field (1) Morphology and Echogenicity of Consolidation Lung The morphology and echogenicity of consolidation lung vary depending on the underlying cause: obstructive lung consolidation (atelectasis) is often accompanied by pleural effusion, with high echogenicity predominating, and the morphology is basically similar to the corresponding lung lobe or segment; inflammatory exudative lung consolidation is predominantly low echogenicity or isoechogenicity, and its morphology can be irregular. (2) Air- or Liquid-Containing Tubular Structures in Consolidation Lung The branch-like arrangement of air- or liquid-containing tubular structures within the consolidation lung is the most important feature for the two-dimensional ultrasonographic diagnosis of lung consolidation. (3) Blood Flow Signals and Blood Flow Spectrum The lung is one of the organs with rich blood supply in the human body, and blood circulation still exists in the consolidated lung. Detection of blood flow signals by ultrasonography is a sensitive and reliable basis for distinguishing lung consolidation from pleural effusion using color Doppler ultrasonography. (4) Internal Masses Ultrasonographic detection of mass-like structures within the consolidated lung is of great value for the etiological diagnosis of lung consolidation. Literature reports indicate that color Doppler ultrasonography has high value in judging the benignity and malignancy of space-occupying lesions, and can even be comparable to CT examination.
