Autofluorescence imaging in colonoscopy

Despite the fact that the story of endoscopy dates back to the middle of the 20 century we are still witness to incredible progress in this field. The spread of endoscopy to all parts of gastrointestinal tube (double balloon endoscopy, [6]) goes arm in arm with focusing on tiny mucosa details (confocal laser endomicroscopy, [7]). There is no doubt that colorectal carcinoma is the main enemy on the colonoscopy front – relatively slow progression from precursors and early malignant lesions gives us an opportunity for cancer prevention and early diagnosis [18]. Our diagnostic efforts are aimed at better detection, identification and staging of lesions. The adenoma and carcinoma detection rate is limited either by the proportion of mucosa visualised during endoscopy or by the low visibility of flat, isochromatic and small lesions [10]. The endoscopist is able to overcome these limitations by means of a meticulous withdrawal technique and by using chromo-endoscopy. His efforts are met by endoscopy improvement – either high-resolution wide-angle endoscopes with magnifying, or techniques of “virtual chromo-endoscopy” (NBI – narrow band imaging Olympus or FICE – Fujinon intelligent chromo-endoscopy). And there are another motives for progression: “Classic” colonoscopy is driven to focus on tiny mucosal details also by means of “competitive” methods, e.g. virtual colonoscopy. Furthermore every new function of the endoscope advances the value of the instrument and is thus important in competition between endoscopic instrument manufacturers. There are several new technologies in addition to that mentioned above [2]: Raman spectroscopy, light-scattering spectroscopy, optical coherence tomography and among them autofluorescence endoscopy is reaching past the borders of clinical practice. The concept of so-called trimodality imaging (endoscopic trimodality imaging – ETMI) is at stake: wide angle high-resolution white light imaging (high resolution endoscopy – HRE), narrow band imaging (NBI) and autofluorescence imaging (AFI) in one endoscope.