Narrow Band Imaging (NBI) Elucidates the Surface Pattern Characteristics of High-Grade Intraepithelial Neoplasia (HGIN) in Barrett's Esophagus (BE)

Abstract

Background & Aim: NBI is a novel endoscopic imaging technique that uses optical filters to enhance the mucosal contrast, thus revealing the superficial mucosal and (micro)vascular patterns. Our aim was to define the mucosal and vascular pattern characteristics of HGIN in BE by using NBI and magnification endoscopy. Patients and Methods: 33 BE patients with history of HGIN were examined with a prototype NBI-system (Olympus, Tokyo, Japan). The system uses a red-green-blue (RGB) sequential illumination light source which is equipped with a conventional set RGB filters for high resolution endoscopy (HRE) and a separate set with narrowed RGB band-pass-ranges and increased relative intensity of blue light for NBI. A high-resolution/magnification endoscope (Olympus GIFQ240-Z) was used. The procedures were performed by two endoscopists with extensive experience in the endoscopic detection of HGIN in BE. Magnified images (HRE and NBI) of suspicious areas were taken followed by biopsies. Unsuspicious areas were also imaged and sampled as controls. Biopsies were evaluated by a single blinded expert pathologist. The images were evaluated by 2 endoscopists (in consensus) who were unaware of the histology. Criteria for image evaluation were developed in a pilot study. Results: 27 areas were found to have HGIN. The corresponding NBI images showed the following factors: irregular/disrupted villous or gyrous mucosal pattern (93%), irregular vascular pattern (89%), and abnormal blood vessels (82%). All areas with HGIN had one or more of these characteristics and 96% had 2 or more factors. The abnormal blood vessels were isolated spiral vessels (60%), vessels with caliber change (40%) and occasional elongated spiral and/or crowded vessels. In 56% there were 2 or more types of abnormal vessels. The control areas (histologically confirmed absence of HGIN) showed either regular mucosal patterns with all blood vessels situated regularly between the mucosal folds (73%) or a flat mucosa with long branching normal-appearing blood vessels (27%). Conclusion: These results confirm that with NBI, irregular mucosal and vascular patterns and the presence of abnormal blood vessels may be specific morphological characteristics of HGIN in BE. All areas with HGIN showed at least one abnormality. NBI may compliment HRE by facilitating precise delineation of lesions and targeting of biopsies. Intra-/inter observer studies are currently being performed to validate these findings. Background & Aim: NBI is a novel endoscopic imaging technique that uses optical filters to enhance the mucosal contrast, thus revealing the superficial mucosal and (micro)vascular patterns. Our aim was to define the mucosal and vascular pattern characteristics of HGIN in BE by using NBI and magnification endoscopy. Patients and Methods: 33 BE patients with history of HGIN were examined with a prototype NBI-system (Olympus, Tokyo, Japan). The system uses a red-green-blue (RGB) sequential illumination light source which is equipped with a conventional set RGB filters for high resolution endoscopy (HRE) and a separate set with narrowed RGB band-pass-ranges and increased relative intensity of blue light for NBI. A high-resolution/magnification endoscope (Olympus GIFQ240-Z) was used. The procedures were performed by two endoscopists with extensive experience in the endoscopic detection of HGIN in BE. Magnified images (HRE and NBI) of suspicious areas were taken followed by biopsies. Unsuspicious areas were also imaged and sampled as controls. Biopsies were evaluated by a single blinded expert pathologist. The images were evaluated by 2 endoscopists (in consensus) who were unaware of the histology. Criteria for image evaluation were developed in a pilot study. Results: 27 areas were found to have HGIN. The corresponding NBI images showed the following factors: irregular/disrupted villous or gyrous mucosal pattern (93%), irregular vascular pattern (89%), and abnormal blood vessels (82%). All areas with HGIN had one or more of these characteristics and 96% had 2 or more factors. The abnormal blood vessels were isolated spiral vessels (60%), vessels with caliber change (40%) and occasional elongated spiral and/or crowded vessels. In 56% there were 2 or more types of abnormal vessels. The control areas (histologically confirmed absence of HGIN) showed either regular mucosal patterns with all blood vessels situated regularly between the mucosal folds (73%) or a flat mucosa with long branching normal-appearing blood vessels (27%). Conclusion: These results confirm that with NBI, irregular mucosal and vascular patterns and the presence of abnormal blood vessels may be specific morphological characteristics of HGIN in BE. All areas with HGIN showed at least one abnormality. NBI may compliment HRE by facilitating precise delineation of lesions and targeting of biopsies. Intra-/inter observer studies are currently being performed to validate these findings.