Assessment of Probe Based Confocal Laser Endo-microscopy for In-vivo Diagnosis of Peripheral Lung Nodules and Masses.

Solitary pulmonary nodule has become a major challenge in respiratory clinical practice. According to published guidelines, their management often requires close CT follow up, PET CT and invasive procedures to obtain a definite histology. In this context, innovative endoscopic techniques refered as navigational bronchoscopy have proved to be efficient, for the localization and sampling of peripheral lung nodules. However, these techniques are unable to differentiate malignant lesions from benign ones, in-vivo, in real time. Confocal endo-microscopy (CELLVIZIO) of the distal lung - also refered as distal lung probe based confocal laser endo-microscopy or alveolar lung endo-microscopy - allows in-vivo imaging of the distal lung structures in real time. This prospective trial we will assess confocal endoscopy as a tool to localize the peripheral lung nodules and to differentiate benign from tumoral lesions. Objective(s) 1. To demonstrate that confocal endo-microscopy is not inferior to navigational endoscopy for the localisation of peripheral lung nodule 2. To demonstrate that confocal endoscopy can differentiate benign from malignant tumors Experimental design: Multicentric prospective controlled trial, conducted in three academic centers, specialized in interventional bronchoscopy, equipped with both navigational bronchoscopy and probe based confocal endo-microscopy. Subjects with peripheral lung nodule requiring navigational bronchoscopy will be explored using both Confocal endoscopy AND navigational bronchoscopy. Confocal probe will be inserted in the same catheter as used for the navigational bronchoscopy and confocal images will be recorded before sampling. An ancillary study using topical methylene blue as in situ will be conducted at the Rouen University Center. An ancillary protocol includes the use of in situ methylene blue deposition and 660 confocal endo-microscopy analysis.

Main assessment criteria: 1. number of lesions localized by confocal endoscopy compared to navigational bronchoscopy 2. Positive and negative predictive values of confocal signs before and after IV fluorophore injection for the diagnosis of cancer. In this this study, positive diagnostic criteria for the localization of peripheral nodule using confocal imaging is a solid pattern as opposed to the usual loose fibered network pattern of the normal alveolar duct. According to this criteria, the confocal imaging procedure will be considered as valid if the number of lesions localized by confocal is not inferior to 90 % of those localized by navigational bronchoscopy. Therefore, probe based confocal laser endo-microscopy will prove valid if it can recognize at least 70 subjects out of the 78 / 120 subjects for which the navigational bronchoscopy is forecasted to localize the peripheral lesion (Cohen concordance Kappa value of 0,74 between confocal and navigational bronchoscopy). A secondary objective will be to describe specific signs of cancer using confocal endoscopy . This will be assessed on the first 30 patients using confocal imaging obtained before and after fluorophore IV injection, in comparison to histology, and confirmed on the following 48 patients.