 Currently Confocal Laser Endomicroscopy CLE is performed using a CLE probe pCLE. The confocal microscope used in pCLE captures microscopic images of untreated in vivo tissue. The microscope uses focused laser light of a defined wavelength and passes it through a confocal aperture. Images are then reconstructed in two dimensions. For pCLE Cellvizio by Mauna Kea Technologies, Paris, France, both the laser scanning unit and light source are outside the body. The laser beam is transported via flexible confocal miniprobes and a distal lens sequentially scans it through a bundle of more than 10000 optical fibers. Confocal miniprobes are flexible, with diameters ranging from 0.9 mm to 2.5 mm. 