Abstract:

Objective To compare the CT signs of different types of drug-resistant pulmonary tuberculosis (PTB) and drug-sensitive PTB (DS-PTB), and to improve the CT diagnosis and differential diagnosis of drug-resis-tant PTB.Methods The clinical and CT scan data of 116 drug-resistant PTB patients admitted to Beijing Chest Hospital from January 1, 2016 to October 31, 2017 were collected for retrospective analysis. There were 26 untreated patients and 90 retreated patients. Also, by the stratified sampling method at a ratio of 1∶4, 31 patients with DS-PTB admitted to this hospital at the same period were selected using random number table method. The 147 cases with drug-resistant TB were divided into 4 groups according to the results of drug sensitivity test (DST), that were multidrug-resistant PTB (MDR-PTB) group (39 cases), extensively drug-resistant PTB (XDR-PTB) group (31 cases), other drug-resistant PTB (DR-PTB) group (46 cases including 41 with mono-resistant PTB (MR-PTB) and 5 with poly-resistant tuberculosis (PDR-PTB)), and DS-PTB group (31 cases). All patients underwent chest CT non-contrast enhanced scan and thin layer reconstruction with a layer thickness of 1.25 mm. The distribution of lung lesions, CT signs and incidence of cavity in patients of different groups were statistically analyzed.Results Contrast analysis of CT findings of the 147 patients showed that the lesions in drug-resistant PTB patients was extensively distributed. The rates of patients with lesions involving three or more lobes were 84.6% (33/39) in the MDR-PTB group, 83.9% (26/31) in the XDR-PTB group, and 91.3% (42/46) in the DR-PTB group, which were higher than that in the DS-PTB group (51.6%, 16/31); the differences were statistically significant (χ ²=8.96, P=0.003; χ ²=7.38, P=0.007; χ ²=15.70, P<0.001). In addition, the lesions were more likely to involve the uncommon sites of TB infection (such as anterior superior lobe and lower lobe basal segment) (94.9% (37/39) in the MDR-PTB group, 87.1% (27/31) in the XDR-PTB group, 95.7% (44/46) in the DR-PTB group, and 51.6% (16/31) in the DS-PTB group; compared with the DS-PTB group, the rates in the MDR-PTB, XDR-PTB, and DR-PTB were statistically higher (χ ²=17.58, P<0.001; χ ²=9.18, P=0.002; χ ²=20.88, P<0.001). However, there was no significant difference in the number and location of lesions among the three drug-resistant PTB groups (MDR-PTB vs XDR-PTB group, MDR-PTB vs DR-PTB group, XDR-PTB vs DR-PTB group: χ ² values were 0.00, 0.38, 0.40 and 0.53, 0.00, 0.88, respectively; P values were 1.000, 0.538, 0.526 and 0.248, 1.000, 0.347, respectively). Contrast analysis of CT signs showed that the incidences of nodules in the lungs and bronchial wall thickening in patients with different types of drug-resistant PTB were 100.0% (39/39) and 87.2% (34/39) in the MDR-PTB group, 100.0% (31/31) and 87.1% (27/31) in the XDR-PTB group, and 100.0% (46/46) and 84.8% (39/46) in the DR-PTB group, respectively, which were significantly higher than that in the DS-PTB group (80.6% (25/31) and 48.4% (15/31)); the differences were statistically significant (χ ²=5.97, P=0.015; χ ²=4.61, P=0.032; χ ²=7.15, P=0.007 and χ ²=12.38, P<0.001; χ ²=10.63, P=0.001; χ ²=11.71, P=0.001). However, there was no significant difference in the incidence of bronchial wall thickness among different drug-resistant PTB groups (MDR-PTB vs XDR-PTB group, XDR-PTB vs DR-PTB group, MDR-PTB vs DR-PTB group: χ ² values were 0.00, 0.00, and 0.10; P values were 1.000, 1.000, and 0.752, respectively). As for the comparison on cavity formation in nodules and consolidations, the incidences in the XDR-PTB and DR-PTB groups were 87.1% (27/31) and 87.0% (40/46), significantly higher than that in the DS-PTB group (58.1%, 18/31); the differences were statistically significant (χ ²=6.57, P=0.010, χ ²=8.32, P=0.004). However, there was no significant difference among different drug-resistant PTB groups (MDR-PTB vs XDR-PTB group, XDR-PTB vs DR-PTB group, MDR-PTB vs DR-PTB group:χ ² values were 1.18, 0.00, and 1.46; P values were 0.277, 1.000, and 0.227, respectively. Conclusion CT signs have diagnostic and differential diagnostic value for drug-resistant and drug-sensitive PTB, but it has no obvious value in identifying different drug-resistant types.

Key words: Tuberculosis, pulmonary, Tuberculosis, multidrug-resistant, Diagnosis, differential, Tomography, X-ray computed, Data interpretation, statistical