Radiological difference between new sputum-positive and sputum-negative pulmonary tuberculosis.

Abstract

Introduction:The current guidelines for the diagnosis of pulmonary tuberculosis (PTB) are based primarily on the demonstration of acid-fast bacilli (AFB) on sputum microscopy and chest radiograph. Knowing various radiological manifestations and their association with sputum microscopy findings can allow for early diagnosis and early initiation of treatment.Aims:This study was performed to compare the chest radiograph features seen in sputum-positive and sputum-negative tuberculosis patients, respectively.Materials and Methods:It was a prospective observational study, which included 147 consecutive patients newly diagnosed and treated as PTB between Jan 2018 and July 2018. Chest X-ray was reviewed by 2 independent radiologists and the findings were compared between sputum-positive and sputum-negative PTB cases. The obtained data were analyzed by statistics using SPSS version 15 for Windows (SPSS Inc., Chicago, IL) and χ2 test and Student t test were used for statistical analysis. P values < 0.05 were considered statistically significant.Results:Out of a total of 147 patients, 38 (25 males and 13 females, mean age 35.23 ± 18.40) were sputum positive and 109 (77 males and 32 females, mean age 36.07 ± 18.15) were sputum negative. The frequency of patchy consolidation (78.94% vs 49.54%) and cavitation (36.84% vs 15.59%) was significantly higher in sputum-positive PTB (P < 0.05). Radiological lesions like nodular shadow (10.09% vs 2.63%), cystic lesion (13.76% vs 5.26%), fibrosis (12.84% vs 7.89%), miliary shadows (2.75% vs 2.63%), and pleural effusion (1.83% vs 0%) were seen more commonly with sputum-negative PTB but the difference was not statistically significant for any of these features. Sputum-positive PTB tends to occur more commonly on the left side (47.36%) compared with sputum-negative PTB (27.52%) (P < 0.05). 34.21% and 35.77% of the chest X-ray lesions were bilateral in sputum-positive and sputum-negative PTB, respectively.Conclusion:Patchy infiltration and cavitation on chest X-ray are seen more frequently in sputum-positive cases of PTB compared with sputum-negative cases.