Abstract:

Objective To explore the difference of CT manifestations between non-tuberculosis mycobacterium (NTM) lung disease patients with diabetes mellitus (DM) and those without DM,in order to improve the differential diagnosis of these two diseases. Methods A retrospective analysis of CT findings of 59 patients with NTM lung disease with DM (group A) and 59 patients with NTM lung disease without DM (group B) who were confirmed by clinical and laboratory tests in Guangzhou Chest Hospital from January to December 2018. The distribution of lesions and CT findings were compared between these two groups.SPSS 21.0 software was used for statistical analysis. χ² test or continuous correction χ² test were used for categorical data, statistical significance was set at P<0.05. Results (1) Lesion distribution: The incidence of lesions located in ≥3 lobes in group A (83.05%, 49/59) was higher than that in group B (66.10%, 39/59), the difference was statistically significant (χ²=4.470, P=0.035). (2) CT manifestations:The incidence of nodule and tree bud sign in group B were 88.14% (52/59) and 71.19% (42/59) respectively,higher than those in group A (67.80% (40/59), 52.54% (31/59)),differences were statistically significant (χ²=7.104, 4.346; P=0.008, 0.037).The incidence of solid shadow, cavity shadow, globular/lumpy shadow and honeycombing shadow in group A were 35.59% (21/59), 67.80% (40/59), 38.98% (23/59) and 25.42% (15/59) respectively, which were higher than those in group B (13.56%(8/59),49.15%(29/59),11.86%(7/59),3.39%(2/59)),differences were statistically significant (χ²=7.726,4.223,8.139,11.614;P=0.005,0.040,0.004,0.001).(3) Cavity lesions: The incidence of thick walled cavity in group A (55.93%, 33/59) was higher than that in group B (20.34%, 12/59), the incidence of thin walled cavity in group B (38.98%, 23/59) was higher than that in group A (22.03%, 13/59),these differences were both statistically significant (χ²=15.841, 3.997; P=0.000, 0.046). Cavities located in ≥3 lobes or the number of cavities ≥3 in group A accounted for 59.32% (35/59) and 57.63% (34/59) respectively, which were significantly higher than those in group B (28.81% (17/59) and 35.59% (21/59)), differences were statistically significant (χ²=11.140, 5.755; P=0.001,0.016). Conclusion Chest CT scan for patients with NTM lung disease with DM is more likely to show lesions with wide distribution, solid shadows, thick walled cavities, globular/lumpy shadows and honeycombing shadows;thin walled cavity, nodule and tree bud sign are more likely to be seen in patients without DM.Those CT manifestations are helpful for differential diagnosis.

Key words: Lung diseases, Mycobacterium infections,atypical, Diabetes mellitus, Comorbidity, Diagnostic imaging, Comparative study, Diagnosis,differential