Differences in pulmonary nodular consolidation and pulmonary cavity among drug-sensitive, rifampicin-resistant and multi-drug resistant tuberculosis patients: a computerized tomography study with history length matched cases.

Background: There have been concerns that literature described radiological feature differences between drug-sensitive pulmonary tuberculosis (DS-PTB) and multidrug-resistant (MDR)-PTB were confounded by that MDR-PTB cases tend to have a longer history. Using history length matched DS-PTB and MDR-PTB cases from a well-defined urban region in Dalian, we retrospectively analysed the CT feature differences of these paired cases with a focus on pulmonary nodular (PN) consolidation and pulmonary cavity (PC).

Methods: There were 33 consecutive MDR-PTB cases [inclusive of rifampicin-resistant (RR) cases, 27 males and 6 females, mean age: 49.2 years], with 19 cases had a history of <1 month and 8 and 6 cases had a history of 1-6 and >6 months respectively. To pair the MDR-PTB cases with history length, matched 33 cases of DS-PTB patients (21 males and 12 females, mean age: 56.5 years) were included. All patients were new PTB without HIV infection. The first CT exams prior to treatment were analysed.

Results: Compared with DS cases, MDR cases had a much higher prevalence of PN (75.76% 45.45%) and a higher number of PN per positive case for PN (6.2 1.53). For the cases >1 month history, MDR-PTB had a higher number of PC per positive case than that of DS-PTB cases (7.18 2.36). To differentiate DS-PTB from MDR-PTB, receiver operating characteristic (ROC) analysis showed a cutoff PN number of ≥3 had 48.5% sensitivity and 93.9% specificity, and a cutoff PC number of ≥4 had 39.4% sensitivity and 84.9% specificity. The lung field distribution of all lesions tended to be wider for MDR-PTB cases. MDR-PTB cases appeared to be associated with a faster progression in the absence of treatment.

Conclusions: MDR-TB is likely intrinsically more invasive than DS-TB. Multiple PN and Multiple PC are promising signs for the suspicion of MDR-PTB on chest imaging.