A new method of diagnosing gastric intestinal metaplasia: narrow-band imaging with magnifying endoscopy

Background and study aims: With endoscopy, there is a high rate of interobserver variability in the identification of gastric intestinal metaplasia, and the endoscopic findings correlate poorly with the histological findings. Previous studies by our group investigating the use of a narrow-band imaging system with magnifying endoscopy (NBI-ME) in the gastric mucosa suggested that the appearance of a light blue crest (LBC) on the epithelial surface may be a distinctive endoscopic finding associated with the presence of intestinal metaplasia. The aim of the present study was to clarify the value of NBI-ME for diagnosing gastric intestinal metaplasia. Patients and methods: The LBC was defined as a fine, blue-white line on the crests of the epithelial surface/gyri. To investigate the histology underlying the appearance of LBC, 44 biopsy specimens were obtained from regions containing LBC and 44 from non-LBC mucosa in 34 patients with atrophic gastritis. Three endoscopists then carried out NBI-ME in 107 consecutive patients to validate the diagnostic accuracy of the novel endoscopic technique. The degree of correlation between the LBC grading and the histological parameters of intestinal metaplasia was then assessed. Results: The LBC grading correlated with cells that were positive for CD10 (P = 0.0001) and Alcian blue (P = 0.036). The appearance of LBC correlated with histological evidence of intestinal metaplasia with a sensitivity of 89% (95% CI, 83-96%), a specificity of 93% (95% CI, 88- 97%), a positive predictive value of 91% (95% CI, 85-96%), a negative predictive value of 92% (95% CI, 87-97%), and an accuracy of 91% (95% CI, 88-95%). Conclusions: In narrow-band imaging with magnifying endoscopy, observation of a light blue crest on the epithelial surface in the gastric mucosa is a highly accurate sign of the presence of histological intestinal metaplasia.