Abstract:

Objective To discuss the CT imaging features of Mycobacterium avium intracellulare complex (MAC) lung disease and Mycobacterium chelonei and abscessus lung disease combined with bronchiectasis, and to improve the differential diagnosis of two diseases. Methods A retrospective analysis of the CT imaging data of 25 cases of MAC lung disease combined with bronchiectasis (Group A) and 26 cases of Mycobacterium chelonei and abscessus lung disease combined with bronchiectasis (Group B). All cases were treated in outpatient or inpatient and were diagnosed clinically in Guangzhou Chest Hospital from January 2017 to December 2017. CT imaging data of patients who were initial diagnosis or had not received anti-NTM treatment were collected. The CT findings and complications of the two groups were compared and analyzed, including bronchiectasis (CT classification, distribution), lung lesions (micronodule, tree in bud, nodules, consolidation, etc.), and cavities (type, distribution). Results There were bronchiectasis, micronodule, tree in bud and thin-walled cavities in two groups. The rates of bronchiectasis in the left lower lobe, micronodules in the left lower lobe, pulmonary consolidation in the right upper lobe and lung volume reduction of Mycobacterium chelonei and abscessus lung disease were 57.69% (15/26), 84.62% (22/26), and 61.54% (16/26) respectively, which was higher than that in MAC lung disease (28.00% (7/25), 56.00% (14/25), 32.00% (8/25)). There was significant statistical differences (χ ²=4.58, 5.03, 4.46, P=0.032, 0.025, 0.035). The cystic bronchiectasis (50.00%, 13/26) was common in Mycobacterium chelonei and abscessus lung disease and columnar bronchiectasis (52.00%, 13/25) often occurs in MAC lung disease. There was significant statistical differences (χ ²=7.69, 6.63, P=0.006, 0.010). Conclusion The incidence of bronchiectasis in left lower lobe, micronodule in left lower lobe and lung volume reduction in Mycobacterium chelonei and abscessus lung disease is higher than that in MAC lung disease. The cystic bronchiectasis often occurs in Mycobacterium chelonei and abscessus lung disease and columnar bronchiectasis is common in MAC lung disease. All these CT manifestations are meaningful for their differential diagnosis.

Key words: Lung diseases, Mycobacterium avium-intracellulare infection, Mycobacterium chelonae, Tomography,X-ray computed, Diagnostic imaging, Comparative study