Utility Of Radial Probe Endobronchial Ultrasound Guided Transbronchial Lung Biopsy In Bronchus Sign Negative Peripheral Pulmonary Lesions

Background: The presence of the bronchus sign on chest computed tomography is associated with an increased diagnostic yield of radial probe endobronchial ultrasound- guided transbronchial lung biopsy (RP-EBUS-TBLB). However, the utility of RP-EBUS-TBLB for bronchus sign negative peripheral pulmonary lesions (PPLs) remains unknown. We investigated the utility of RP-EBUS-TBLB in bronchus sign negative PPLs.Methods: We retrospectively reviewed data from 109 patients who underwent RP-EBUS for bronchus sign negative PPLs from January 2019 to August 2020. TBLB was performed using RP-EBUS with a guide sheath and without fluoroscopy. The EBUS visualization and TBLB diagnostic yields were assessed. Multivariable logistic regression analyses were used to identify factors affecting the EBUS visualization and diagnostic yields.Results: The EBUS visualization yield was 74.1% (68/109). Of the 109 lung lesions, 92 were definitively diagnosed. The overall diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 50.5% (55/109), 34.9% (29/83),100% (26/26),100% (29/29), and 32.5% (26/80), respectively. In multivariable analyses, the size of the lesion (a. 20 mm; odds ratio [OR], 2.62; 95% confidence interval (CI], 1.16-5.93; P= 0.021) and the distance from the pleura (> 10 mm; OR, 2.37; 95% CI, 1.02-5.52; P= 0.045) were associated with EBUS visualization. Regarding diagnostic yield, having the probe within the lesion (OR, 28.50; 95% CI, 6.26-129.85; P< 0.001) and a solid lesion (OR, 14.58; 95% CI, 2.64-80.38; P= 0.002) were associated with diagnostic success. Pneumothorax and hemoptysis occurred in 3.7% (4/109) and 0.9% (1/109), respectively, of the patients.Conclusion: RP-EBUS-TBLB using a GS can be considered a diagnostic method in bronchus sign negative solid PPLs. Having the probe within the lesion and a solid lesion were important for diagnostic success. Complication rates were acceptable.