EUS-guided needle-based Confocal Laser induced Endomicroscopy (nCLE): a correlation study of “through the needle' imaging with normal histology in a porcine model

Background: Endoscopic probe-based Confocal Laser Endomicroscopy (pCLE) enables in-vivo real time imaging of cells and blood flow within the mucosal layer of the GI tract. Recently, a prototype high-resolution CLE probe has been developed (Cellvizio®, Mauna Kea Technologies) which can be introduced through a 19g FNA needle creating the possibility for needle-based Confocal Laser Endomicroscopy (nCLE). The feasibility and quality of images obtained using EUS-guided nCLE in solid organs such as the pancreas, liver, spleen, gallbladder and lymph node have not been clearly correlated with normal histology.

Aim: The aim of this study was to determine the feasibility and image quality of in-vivo EUS-guided nCLE of abdominal organs and benign lymph nodes in the porcine model.

Methods: Two Yorkshire pigs (30–35kg) were examined under general anesthesia. EUS-guided organ puncture (pancreas, liver, spleen, gallbladder and lymph node) was performed through the stomach or esophagus using an Olympus linear echoendoscope (GFUCT140-AL5) and a prototype 19g access needle (Cook Medical). After intravenous injection of fluorescein (2 mL 10% solution), the nCLE probe was inserted through the previously placed EUS-guided needle and advanced just beyond the needle tip. Further advancement of the probe within the organ was accomplished by either probe or needle extension. Endoscopic, EUS and nCLE images were all recorded on high quality video capture. Histologic correlations were made on H&E stains from harvested organs.

Results: Technical feasibility to introduce the nCLE probe via EUS into all four abdominal organs and mediastinal lymph nodes was 100%. The prototype access needle allowed for easy maneuverability of the nCLE probe, without requiring pre-loading of the probe. All nCLE images were paired with corresponding H&E slides and the image qualities (stills and video) were determined to be fair to excellent and histological features could be identified in all nCLE images.

Conclusions: EUS-guided nCLE of abdominal organs and lymph nodes is feasible and correlates well with histology. EUS-guided nCLE of solid organs and lymph nodes represents an exciting new frontier for endosonographers with the potential to visualize in-vivo “virtual histology” within any structure, organ, or lesion that is accessible by EUS.