Narrow Band Imaging Project on Barrett's Esophagus

Overview

Narrow Band Imaging(NBI) improves image contrast by allowing the blue light centered at 415 nanometers which is heavily absorbed by oxyhemoglobin to highlight the tissue's microvasculature and enhances detail on the surface of the mucosa revealing subtle changes. Barrett's esophagus(BE) has the mucosal and vessel changes during cancer transformation by angiogenesis. The ability of the NBI scope to visualize submucosal vessels forms the premise for the prediction of dysplasia in BE mucosa. NBI images of the BE mucosa obtained during endoscopy will be classified by academic endoscopists and community endoscopists initially. The endoscopists will then be asked to predict histopathology based on the NBI surface patterns. This clinical trial will evaluate the inter-observer agreement of a simple, consensus driven narrow band imaging (NBI) classification system of surface patterns and its ability to differentiate dysplastic versus non-dysplastic Barrett's esophagus(BE) in patients undergoing BE screening or surveillance in expert academic centers and in community GI practice as well. Their performance will be evaluated for accuracy, sensitivity, specificity, positive predictive value and negative predictive value of each pattern that is visualized on NBI.

This is a multicenter, prospective, double-blinded study of NBI images from 50 patients enrolled in the study. Patients undergoing BE screening and BE surveillance will be enrolled into the study. After meeting eligibility criteria, and obtaining an informed consent, patients will undergo their routine upper endoscopic examination using white light endoscopy. During the course of the upper endoscopy, the BE surface patterns will be carefully examined with the endoscope in overview mode (with the endoscope in the center of the esophageal lumen) and then in close proximity to the BE surface (approximately 3-5 mm away from the mucosa). In each of these positions, a maximum of 4 high quality images will be obtained from different surface patterns initially with WLE and then using NBI. Image capture will be standardized. All the images will be classified based upon a simplified NBI classification system using two main criteria:(1)mucosal pattern(regular/irregular/uncertain) and (2)vascular pattern (regular/irregular/uncertain). All images will be captured using a high-definition, NBI endoscope (190 endoscopes-GIF-HQ 190 \[dual focus\],Olympus Inc) and stored in the high quality TIFF format. After images have been obtained, target biopsies will be obtained from each area and submitted for histopathological evaluation in separate jars. From the reports on NBI patterns from the images by Gastroenterologist and corresponding histopathological details, the accuracy and interobserver agreement of this NBI classification system will be determined.