CT and microbiologic follow-up in primary multidrug-resistant pulmonary tuberculosis

Background: Little attention has been paid to the initial and follow-up computed tomography (CT) features in primary multi-drug resistant tuberculosis (pMDR-TB) setting. Purpose: To describe serial CT findings and clinical course of pMDR-TB with antibiotic treatment. Material and Methods: For the last 10 years, 340 MDR-TB patients were managed in a tertiary referral hospital. Among them, we included 44 (27 men, 17 women; mean age, 40 years; age range, 20-81 years) pMDR-TB patients; 37 treated with chemotherapy only and seven treated with medical therapy plus surgery. CT findings were evaluated regarding tree-in-bud sign, acinar nodule, peribronchial, segmental or lobar consolidation and cavity, and their extent. Sputum negative conversion rates and serial CT scores were assessed. To compare changes in disease extent between initial and follow-up CT studies, paired t-test was performed. Results: Two most frequent patterns of lung abnormality were tree-in-bud sign (37 of 44, 84.1%) and acinar nodule (41 of 44, 93.2%). Among 37 patients treated with chemotherapy only, 36 showed negative sputum conversion within 3 months after second-line drug commencement, maintained for > 12 months. The other seven undergoing surgery during medical treatment showed excellent outcome with negative conversion achieved within one month after surgery and maintained for > 12 months. CT scores showed significant decrease on serial CT studies (P<0.001) in all. Conclusion: In pMDR-TB, two most frequent abnormal CT patterns are tree-in-bud sign and acinar nodule. In 98% of patients, negative sputum conversion is achieved, and CT score also shows decrease in extent after TB chemotherapy.