Chromoscopic endomicroscopy: in vivo cellular resolution imaging of the colorectum.

Advances in imaging technology and engineering have now permitted functional integration of a confocal endomicroscope into the distal tip of a conventional video colonoscope enabling imaging of the surface epithelium and the underlying lamina propria during ongoing video endoscopy. For the first time, the endoscopist is now able to resolve the surface and subsurface mucosa at cellular resolution in vivo and in real time. A new era in endoscopic imaging has therefore begun - histoendoscopy. In addition to providing a high-accuracy in vivo optical biopsy tool for the differentiation between benign hyperplasia, intra-epithelial neoplasia and carcinoma in sporadic cohorts, endomicroscopy with targeted biopsies has now been shown to increase the yield of intra-epithelial neoplasia complicating ulcerative colitis. Furthermore, recent data examining endomicroscopic molecular ex vivo imaging using anti-CD44v6 antibody has identified aberrant crypt foci based on their surface molecular expression. Receptor overexpression in vivo in humans may, in the near future, be exploited for the diagnosis of inflammation, neoplasia and in predicting targeted molecular therapy. Endomicroscopy will be key to this immuno-imaging interface. Within the present review, we discuss the current clinical evidence in support of confocal endomicroscopy and explore the new diagnostic possibilities for this technology.