Clinical applicability of gastroscopy with narrow-band imaging for the diagnosis of Helicobacter pylori gastritis, precancerous gastric lesion, and neoplasia

Abstract

Premalignant gastric lesions such as atrophic gastritis and intestinal metaplasia frequently occur in subjects with long-term Helicobacter pylori (H. pylori) infection. The regular arrangement of collecting venules (RAC) is seen in the normal gastric corpus, whereas mucosal swelling and redness without RAC are observed in H. pylori-infected mucosa. Despite successful H. pylori eradication, the presence of atrophic gastritis and/or gastric intestinal metaplasia (GIM) is a risk factor for gastric cancer. With the development of advanced imaging technologies, recent studies have reported the usefulness of narrow-band imaging (NBI) for endoscopic diagnosis of atrophic gastritis and GIM. Using NBI endoscopy with magnification (M-NBI), atrophic gastritis is presented as irregular coiled microvessels and loss of gastric pits. Typical M-NBI endoscopic findings of GIM are a light blue crest and a white opaque substance. Based on the microvascular patterns, fine network, core vascular, and unclear patterns are useful for predicting gastric dysplasia in polypoid lesions. For diagnosis of early gastric cancer (EGC), a systematic classification using M-NBI endoscopy has been proposed on the basis of the presence of a demarcation line and an irregular microvascular/microsurface pattern. Furthermore, M-NBI endoscopy has been found to be more accurate for determining the horizontal margin of EGC compared to conventional endoscopy. In this review, we present up-to-date results on the clinical usefulness of gastroscopy with NBI for the diagnosis of H. pylori gastritis, precancerous gastric lesion, and neoplasia.

Keywords: Gastroscopy, Narrow-band imaging, Magnification, Helicobacter pylori, Atrophic gastritis, Intestinal metaplasia, Dysplasia, Cancer

Core tip: Image-enhanced endoscopy techniques such as narrow-band imaging (NBI) improve the diagnosis of Helicobacter pylori infection, atrophic gastritis, and gastric intestinal metaplasia (GIM). When NBI is combined with magnifying endoscopy, typical endoscopic findings can clearly be observed. Thus, the extent and severity of GIM can be endoscopically evaluated by close mucosal observation. Based on the microvascular patterns, fine network, core vascular, and unclear patterns are useful for predicting gastric dysplasia in polypoid lesions. When the endoscopists find a small flat or depressed lesion, magnifying NBI endoscopy is helpful for differentiating between cancer and gastritis. The presence of a demarcation line and an irregular microvascular/microsurface pattern are highly suspicious for high grade dysplasia and cancer. For endoscopic treatment of early gastric cancer, the horizontal tumor margin can be assessed by magnifying NBI endoscopy.