Abstract:

Objective To analyze the similarities and differences of CT signs of cavity due to Mycobacterium kansasii lung disease and pulmonary tuberculosis. Methods A retrospective study was conducted, 45 patients with cavity due to Mycobacterium kansasii lung disease diagnosed by clinical and laboratory examinations of Suzhou Fifth People's Hospital from January 2018 to June 2020 were selected as the observation group; 50 patients with cavity due to pulmonary tuberculosis of the same period were selected as the control group. The image signs, such as number of cavities in the lungs, the extent of pulmonary lobes involved, the distribution location, shape, size, wall thickness, internal and external wall smoothing, contents and surrounding structures, of the two groups were compared and analyzed. Results A total of 60 cavities appeared in 45 patients in the observation group, and there were 75 cavities appeared in 50 patients in the control group. The proportion of patients with 3 or more cavities in the observation group was significantly lower than that of the control group (2.2% (1/45) vs. 14.0% (7/50), χ ²=4.26, P=0.039). In the observation group, the proportions of cavities in the upper lobe of the right lung and in the outer zone were both significantly higher than those in the control group (70.0% (42/60) vs. 36.0% (27/75), χ ²=15.42, P=0.000; 91.7% (55/60) vs. 58.7% (44/75), χ ²=18.56, P=0.000); the proportion of irregular voids was significantly higher than that in the control group ((25.0% (15/60) vs. 2.7% (2/75), χ ²=15.11, P=0.000). The cavity wall thickness of the observation group was significantly lower than that of the control group (M(Q₁,Q₃), 2.3 (0.9, 8.3) mm vs.3.6 (1.0,10.8) mm, U=-4.34, P=0.000). In the observation group, the smoothing ratio of the inner wall of the cavity was significantly lower than that of the control group (85.0% (51/60) vs. 96.0% (72/75), χ ²=4.98, P=0.026), and the ratio of smoothing the outer wall was more than that of the control group (85.0% (51/60) vs. 57.3% (43/75), χ ²=12.07, P=0.001), the incidence of satellite foci around the cavity was significantly lower than that in the control group (38.3% (23/60) vs. 70.7% (53/75), χ ²=14.16, P=0.000); the incidence of pleural thickening adjacent to the cavity was significantly higher than that in the control group (91.7% (55/60) vs. 69.3% (52/75), χ ²=10.11, P=0.001). Conclusion There were differences in CT signs between the cavity lesions of Mycobacterium kansasii lung disease and the cavities of tuberculosis, which could provide a basis for clinical diagnosis.

Key words: Mycobacterium kansasii, Mycobacterium tuberculosis, Lung diseases, Tomography, spiral computed, Comparative study