Utility of rapid on-site evaluation during bronchoscopy in the diagnosis of pulmonary tuberculosis.

Abstract

Introduction：The diagnostic value of rapid on-site evaluation (ROSE) in bronchoscopy for lung tumors has been widely researched. However, the diagnostic efficacy of ROSE for pulmonary tuberculosis has not been extensively assessed yet. This study aimed to examine the value of ROSE in diagnosing pulmonary tuberculosis during bronchoscopy, and the relationship between ROSE cytology patterns and acid-fast bacilli (AFB) smears and mycobacterial cultures. Methods：A retrospective study was conducted at a single respiratory endoscopy centre, including 418 patients under clinical or radiological suspicion of having pulmonary tuberculosis who underwent bronchoscopy. In addition to the use of ROSE and definitive cytology, material obtained by aspiration/lavage or brushing was sent for AFB smear and mycobacterial culture. If histopathological examination was required, endobronchial biopsy (EBB), transbronchial lung biopsy (TBLB) and transbronchial needle aspiration (TBNA) were performed at the discretion of the clinician. A composite reference standard (CRS) was used as the diagnostic gold standard for this study. The diagnosis obtained by ROSE was compared with the final diagnosis. Results：Of the 418 patients studied, 282 (67.5%) were diagnosed on the basis of bronchoscopic findings, as follows: pulmonary tuberculosis, in 238 (84.4%); Non-tuberculosis (Non-TB) ，in 44 (15.6%). In 238 pulmonary tuberculosis patients, ROSE cytology showed granulomas without necrosis were observed in 107 cases, granulomas and necrosis in 51 cases, caseous necrosis only in 25 cases, and non-specific inflammation in 55 cases. For the diagnosis of tuberculosis according to CRS, ROSE showed the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) was 76.9%, 68.2%, 92.9% and 35.3%, respectively. The positivity rate for bacterial detection by acid-fast staining and culture at bronchoscopy was 51.7%. The cytological pattern showed a higher detection rate for bacteria in cases of necrosis. Discussion：The application of rapid on-site evaluation (ROSE) during bronchoscopy is a straightforward procedure that delivers an immediate and precise assessment regarding the adequacy of collected samples, enabling a preliminary diagnosis of pulmonary tuberculosis. ROSE has exhibited a higher sensitivity in detecting pulmonary tuberculosis compared to microbiological examinations. In addition, the cytological presentation of ROSE tends to show a higher positivity rate for microbiological testing in caseous necrosis. Therefore, samples with these characteristics should be prioritised for microbiological examination after on-site evaluation.