[Comparison of ultrathin bronchoscopy with conventional bronchoscopy for the diagnostic value of peripheral pulmonary lesions].

Objective: To assess and compare the diagnostic efficacy of next-generation ultrathin bronchoscopy (UTB) and conventional bronchoscopy (CB), both combined with radial endobronchial ultrasound (r-EBUS), in the evaluation of peripheral pulmonary lesions (PPL). Methods: A cohort of 39 patients with PPL who underwent multimodal bronchoscopy at Dushu Lake Hospital, Soochow University, from June 1, 2021 to May 31, 2023 was consecutively enrolled. A single bronchoscopist performed multimodal bronchoscopies using CB (external diameter 4.9 mm or 5.9 mm, working channel diameter 2 or 3 mm, CB group) for transbronchial biopsy under r-EBUS guidance (rEBUS-TBLB), followed by UTB (external diameter 3 mm, working channel diameter 1.7 mm, UTB group) for transbronchial biopsy under r-EBUS guidance. Pathological findings and a 6-month clinical follow-up were used as the gold standard to compare the diagnostic yield of biopsy specimens, ultrasound characteristics, and localization rates of the two bronchoscope types. The aim was to evaluate the clinical application value of UTB combined with r-EBUS. Binary variables were analysed using the McNemar test for paired data. Continuous variables or ranked data were analysed using the Wilcoxon signed-rank test for paired data. Results: The diagnostic yields for UTB and CB groups were 66.67% (26/39) and 30.77% (12/39), respectively, with the UTB group significantly surpassing the CB group (χ2=10.56, P=0.001, 1-β=0.968). r-EBUS with CB exhibited no visible lesion in 13 cases, adjacent to the lesion in 19 cases, and within the lesion in 7 cases.Substitution of UTB resulted in r-EBUS images changing from no visible lesion to adjacent to the lesion in 7 cases, from no visible lesion to within the lesion in 3 cases, and from adjacent to the lesion to within the lesion in 12 cases. The positioning of the r-EBUS probe in relation to the lesions improved significantly with UTB usage (Z=-4.46, P<0.001). Localization rates (number of patients with "within" or "adjacent to" the image/total number of patients) for UTB and CB were 92.30% (36/39) and 66.67% (26/39), respectively (χ2=8.10, P=0.002). UTB improved r-EBUS probe localization rates. The diagnostic yields of UTB were higher than CB for solid lesions, lesions>30 mm in diameter, non-upper lobar location, benign or malignant lesions and lesions with or without a bronchus sign. Conclusion: The UTB group demonstrated a significantly higher diagnostic yield than the CB group, providing superior r-EBUS probe images, and a significant diagnostic advantage for PPL.