HRCT Chest Findings in Smear-Negative Presumptive Active Pulmonary Tuberculosis Cases: A Cross-Sectional Study in Tertiary Center

Abstract

Background:

Tuberculosis (TB), a leading global infectious killer caused by Mycobacterium tuberculosis, significantly impacts public health, especially in regions like Nepal where a large portion of the population harbors latent infection. Diagnosing pulmonary TB, particularly in sputum smear-negative cases, presents a challenge due to low bacterial loads. This study aims to evaluate high-resolution computed tomography (HRCT) findings in sputum smear-negative presumptive pulmonary tuberculosis (SNPT) cases, utilizing the Xpert MTB/RIF assay as the microbiological benchmark for bacteriological confirmation and comparing these with clinically diagnosed instances.

Methods:

This cross-sectional study included 71 patients diagnosed with new onset SNPT between December 2021 and December 2022. Demographic, clinical, and HRCT data were recorded and analyzed using Microsoft Excel and SPSS. HRCT findings were assessed, and the Xpert MTB/RIF test results were noted. Statistical analysis used the Fisher’s Exact test to determine significant associations, with a p-value <0.05 considered significant.

Results:

Among the 71 patients, centrilobular nodules, lymphadenopathy, consolidations, and tree-in-bud patterns were the predominant HRCT features. Bacteriologically confirmed SNPT cases exhibited a higher prevalence of centrilobular nodules, tree-in-bud patterns, and macronodules compared to clinically diagnosed cases. The apical, posterior, and superior segments were the most commonly affected lung segments. HRCT diagnostic criteria, combining multiple features, effectively ranked TB risk, with higher ranks correlating with bacteriologically confirmed cases.

Conclusion:

HRCT plays a pivotal role in diagnosing SNPT, revealing critical markers like centrilobular nodules and tree-in-bud patterns, especially in bacteriologically confirmed cases. Despite limitations, this study highlights HRCT’s diagnostic value, advocating for its broader application in TB-endemic regions to improve diagnostic accuracy and patient management.