Advances in colonic imaging: new endoscopic imaging methods.

There is a need for better endoscopic visualization in specific circumstances like detection of flat colorectal lesions and dysplasia-screening in ulcerative colitis. Chromoendoscopy is a technique with proven success, but many more, novel endoscopic techniques are currently under investigation. In this article different point measurement and still imaging methods are discussed: Raman spectroscopy, elastic (light) scattering spectroscopy, fluorescence spectroscopy, optical coherence tomography and confocal laser microscopy. Furthermore, real-time endoscopic imaging methods are discussed. These include narrow band imaging, fluorescence imaging and endocytoscopy. The results of fluoroscence imaging might be improved by application of photosensitizers or coupling of fluorescent dyes to tumour-related antigens (immunoscopy). Most of these techniques still have to be developed further and are not yet available for routine use. In our opinion, a combination of a red-flag technique and a microscopic technique carries an enormous potential.