Imaging Enhanced Endoscopy for the Screening of Barrett's Esophagus

Barrett ' s esophagus, defined as a pathological finding of metaplastic change of esophageal mucosa from squamous to columnar epithelium, is a tongue-like extension of salmon-colored mucosa from the gastroesophageal junction by endoscopy (1 2,3) . Endoscopic abnormalities suggestive of BE which has not been confirmed by histology, are defined as endoscopically suspected esophageal metaplasia (ESEM) (2). Barrett's esophagus is considered a precancerous lesion of esophageal adenocarcinoma (4 5) and it's mandatory for accurate diagnosis of BE. The pathogenesis of BE has also been closely associated with gastroesophageal reflux disease (6). In Western countries the reported prevalence of BE has varied from 0.9 to 4.5 % (3,7,8) in the general population and 6.3 to 13.6 % (9 - 12) in patients with GERD. For reliably rating differences of severity of endoscopically identified lesions among studies or quantify progression or regression of BE, International Working Group for the Classification of Oesophagitis (IWGCOA) proposed new classification of BE, the Prague C and M criteria (13) for defining the extent of BE based on the circumference (C) and maximum (M) of the lesion. This standard grading system could allow comparison of the severity of BE and aid in following the natural course of BE Image-enhanced endoscopy (IEE) compromises various means of enhancing contrast during endoscopy using dye, optical, and/or electronic methods IEE allows improved visualization of lesions and can be used to gain insight into the pathology of the lesion, Recent progress in optics and computerized processing of endoscopic images, such as narrow band image (NBI) and Fuji intelligent Chromoendoscopy (FICE), provide an optical and/or electronic enhancement of the mucosal structures. Most recently, the EPKi-processor (Pentax, Tokyo, Japan) developed i-Scan, a novel endoscopic post-processing light filter technology using delicate software algorithms with real-time image mapping technology, which can provide detailed analysis based on vessel (i-Scan V), pattern (i-Scan P), or surface architecture (i-Scan SE). Resolution of about 1.25 mega pixels per image could be provided by the computer-controlled digital processing. The SE-mode could be used for the identification of the morphological changes of esophageal mucosa. Accordingly, i-Scan e- and b-modes could be used to further evaluate the lesions, such as the regularity of vascular pattern and the presence of the abnormal vessels.

According to previous study (14), Ki67 and p53 immuno-histochemistry could reduce interobserver variation in assessment of Barrett's oesophagus. These IHC methods correlate with the severity of dysplasia very well and are useful supplementary prognostic markers In our study, we use the image enhanced endoscopy to observe the endoscopically suspected esophageal metaplasia and record it with Prague C and M criteria grading system. Immuno-histochemical staining was used as supplementary prognostic markers. Our aim is to evaluate the efficacy of imaging enhanced endoscopy for screening of Barrett's esophagus and evaluation of invasiveness.