Abstract: Objective To explore and compare the characteristics of CT imaging in nontuberculous mycobacterial (NTM) lung disease with secondary pulmonary tuberculosis. Methods From July 2009 to Dec 2012, 41 patients which were confirmed as nontuberculous mycobacterial lung disease admitted in Shanghai Pulmonary Hospital were enrolled as study group, and 41 patients with smear- or culture- positive secondary pulmonary tuberculosis were enrolled from 1026 patients admitted in the same hospital using systematic random sampling as control. The data of thin-section chest CT imaging were analyzed retrospectively. The patterns of lung lesions, including centrilobular nodules, large nodules, cavity, consolidation, bronchiectasis, distribution of lesions, were compared. Statistical comparisons were performed with the t-tests for univariate analysis, and a logistic regression method was used for multivariate analysis.  Results Based on univariate analysis, bronchiectasis ((95.1%, 39/41) vs (12.2%, 5/41), χ²=53.408, P<0.001) was more frequently seen in NTM patients. On the other hand, consolidation ((7.3%, 3/41) vs (31.7%,13/41), χ²=6.290, P=0.012) were more frequently seen in secondary pulmonary tuberculosis patients. A logistic regression analysis demonstrated that bronchiectasis was significant CT fin-dings associated with NTM (β=5.613, Waldχ²=22.717, P<0.001, OR=273.843, 95%CI=27.237-2753.221). Conclusion The thin section CT finding of NTM has certain characteristics which may be helpful to clinical diagnosis for NTM before bacteriological result.

Key words: Mycobacterium infactions, , nontuberculous, Tuberculosis, pulmonary/radiography, Tomography, X-ray computed