Abstract: Background and purpose: Transbronchial lung biopsy has the advantage of low complications. However the diagnostic rate of conventional bronchoscopy is extremely low for peripheral pulmonary nodules. The current differences in the diagnostic rate and safety of navigation techniques for improving the diagnosis rate of peripheral pulmonary nodules are not well understood. Therefore, this study compared the diagnostic yield and safety of radial endobronchial ultrasound (R-EBUS), LungPro Virtual Bronchoscopy Navigation System and combination of LungPro Virtual Bronchoscopy Navigation System and R-EBUS. At the same time, usefulness of cytological rapid on-site evaluation (C-ROSE) for the diagnosis of peripheral pulmonary lesions was evaluated. Methods: From Nov. 2018 to Apr. 2019, a total of 255 patients with pulmonary lesions who underwent bronchoscopy and met the criteria of inclusion and exclusion in the Third Affiliated Hospital of Kunming were enrolled. The subjects were randomly divided into one of three groups: radial endobronchial ultrasound group (R-EBUS group)(85 patients), LungPro Virtual Bronchoscopy Navigation System group (LungPro group) (85 patients) and combination of LungPro Virtual Bronchoscopy Navigation System and R-EBUS group (combined group) (85 patients). C-ROSE was carried out in these three groups. Sampling was performed by transbronchial lung biopsy. The diagnostic yield, complications, procedure time and operative blood loss were observed. Results: The diagnostic yields for peripheral pulmonary lesions of LungPro group and combined group were 85.9% (73/85) and 87.1% (74/85), significantly higher than that of R-EBUS group ［72.9%(62/85)］ (P＜0.05). There was no significant difference in diagnostic yield between LungPro group and combined group (P＞0.05). The navigation time and operation time of R-EBUS group were (11.34±12.95) min and (28.37±1.98)min, significantly longer than those of LungPro group [(3.72±0.71) min and (19.35±1.53) min] and combined group ［(6.12±1.14) min and (21.00±1.97) min］(P＜0.001). The navigation time and operation time of LungPro group were shorter than those of combined group (P＜0.001). The operative blood loss was (4.18±1.42) mL in R-EBUS group, (4.26±1.00) mL in LungPro group and (4.41±1.19) mL in combined group. There was no significant difference in operative blood loss among three groups (all P>0.05). Two cases of pneumothorax were observed in R-EBUS group, 2 cases of pneumothorax and 1 case of pleural reaction were observed in LungPro group, and 1 case of pneumothorax was observed in combined group. No severe adverse event occurred. The diagnostic accordance rate of C-ROSE was 83.9%. The diagnostic sensitivity, specificity, positive predictive value and negative predictive value of C-ROSE were 83.7%, 84.3%, 87.9% and 79.1%, respectively. Conclusion: LungPro Virtual Bronchoscopy Navigation System can help to improve the diagnostic yield for peripheral pulmonary lesions with a very low complication rate, short navigation time and operation time．Combination of LungPro Virtual Bronchoscopy Navigation System and C-ROSE can significantly improve specimen adequacy and decrease the number of biopsy and needle passes necessary to achieve an adequate pathological diagnosis with lower complication rate.

Key words: Bronchoscope, LungPro Virtual Bronchoscopy Navigation System, Radial endobronchial ultrasound, Cytological rapid on-site evaluation, Peripheral pulmonary lesions