Abstract:

Objective: To investigate the ultrasound imaging features of subpleural pulmonary tuberculosis and bacterial pneumonia in a high-altitude environment. Methods: Using a retrospective research method, 47 patients diagnosed with subpleural pulmonary tuberculosis (pulmonary tuberculosis group) and 40 patients diagnosed with bacterial pneumonia (pneumonia group) at Yunnan Provincial Infectious Disease Hospital from January to December 2024 were selected as the study subjects. All patients underwent routine ultrasound examination to compare the ultrasound imaging features of the two groups, including lesion morphology (wedge-shaped, quasi circular, irregular), fragmentation sign (uneven local echoes with scattered bright spots), waterfall sign (layered hypoechoic area extending parallel to the pleural line, recording its extension range and clarity of layered structure), and liquefaction necrosis lesion (gas hyperechoic or “comet tail sign” visible inside the hypoechoic area). Results: In the pulmonary tuberculosis group, wedge-shaped lesions accounted for 61.7% (29/47), round lesions for 29.8% (14/47), and irregular lesions for 8.5% (4/47). In the pneumonia group, wedge-shaped lesions accounted for 62.5% (25/40), and round lesions for 37.5% (15/40). There was no statistically significant difference in lesion morphology between the two groups (Fisher’s precision probability test, P>0.05). The proportion of patients with fragmented signs in the pulmonary tuberculosis group was 29.8% (14/47), significantly lower than the 82.5% (33/40) in the pneumonia group, and the difference was statistically significant (χ²=14.490, P=0.001). The incidence of “waterfall sign” in the pulmonary tuberculosis group was 61.7% (29/47), significantly higher than the 27.5% (11/40) in the pneumonia group, and the difference was statistically significant (χ²=10.177, P=0.001). The incidence of liquefied necrosis lesions in the pulmonary tuberculosis group was 80.9% (38/47), significantly higher than the 25.0% (10/40) in the pneumonia group, and the difference was statistically significant (χ²=28.301, P=0.001). 68.1% (32/47) of the pulmonary tuberculosis group had peripheral blood flow signals, and there were no cases of central blood flow; in the pneumonia group, 77.5% (31/40) had peripheral blood flow signals, while 2.5% (1/40) had central blood flow signals, with no statistically significant difference (χ²=0.976, P=0.317). Conclusion: The ultrasound imaging of pulmonary tuberculosis in high-altitude environments is characterized by layered hypoechoic (waterfall sign) with strong gas echoes, while bacterial pneumonia is mainly characterized by fragmented signs and small liquefied lesions, with blood flow signals mainly distributed in the periphery.

Key words: Tuberculosis, pulmonary, Pneumonia, bacterial, Ultrasonography, Disease attributes, Comparative study