Multi-modal tissue sampling in cone beam CT guided navigation bronchoscopy: comparative accuracy of different sampling tools and rapid on-site evaluation of cytopathology

Background Advanced technological aids are frequently used to improve outcome of transbronchial diagnostics for peripheral pulmonary lesions. Even when lesion access has been confirmed by 3D imaging, obtaining an accurate tissue sample however remains difficult. In this single institution study, we evaluate the comparative accuracy of different sampling methodologies and the accuracy of rapid on-site evaluation of cytopathology (ROSE) in navigation bronchoscopy cases where imaging has confirmed the catheter to have accurately accessed the lesion. Methods All consecutive navigation bronchoscopies in between December 2017- June 2020 performed in a room with a cone beam CT (CBCT) system where catheter position was intra-procedurally confirmed to be within or adjacent to the lesion by cone beam CT and augmented fluoroscopy were included. Individual tool outcomes were compared against one another and follow-up outcome. Results A mean of 11.39 samples using 2.93 tools were obtained in 225 lesions (median diameter 15 mm, 195 patients). A correct diagnosis was most often obtained by forceps (accuracy 70.6%), followed by 1.1 mm cryoprobe (68.4%), needle aspiration (46.7%), 1.9 mm cryoprobe (41.2%), brush (30.3%) and lavage (23.7%). Procedural outcome corresponded to follow-up outcome in 75.1% of lesions (80.5% of patients). Accurately diagnosed lesions were sampled significantly more often (11.91 vs. 9.72 samples, P=0.014). In cases where procedural outcome proved malignant, ROSE had also detected this in 47.5%. Conclusions Of all clinically available biopsy tools, the forceps showed most often accurate. However, extensive multi-modal sampling resulted in highest diagnostic accuracy. A hypothetical multi-modal approach of only using forceps and needle aspiration provided eventual diagnostic outcome in 91.7% of successfully diagnosed lesions. In the circumstances of our study, confirmation of malignancy on ROSE did not reduce number of biopsies taken nor biopsy time. Future research on how to improve the accuracy and effectivity of tissue sampling is needed.