Endoscopic procedure The endoscopic procedures will be performed with a high-resolution endoscope (Olympus GIF-Q240Z, GIF-Q160Z, or more recent versions) that has the capability of performing NBI with the push of a switch. Standard methods of conscious sedation and cardiopulmonary monitoring will be used during each procedure. The distal esophagus will be carefully inspected for the presence of erosions, nodules and plaques. The presence and size of hiatal hernia will be recorded. A plastic disposable distal attachment cap (e.g. Olympus D-201-11802) with a free distal distance of 2-3 mm will be attached to the endoscope in order to fix mucosal areas of interest until images and biopsies have been taken. The endoscopist will be blinded to the previous BE histology of the patient. The classification of mucosal and vascular patterns will be performed in a standardized manner into groups as described above. Details of endoscopy findings and digital video recordings will be entered into an endoscopy form .