Visualization of Absorbed Lipid in the Normal Duodenal Epithelium Using Magnifying Endoscopy with Narrow-Band Imaging

Background Subepithelial microvascular pattern cannot be visualized on the surface of adenoma and carcinoma by magnifying endoscopy due to a white opaque substance (WOS), which consists of minute lipid droplets accumulated in the neoplastic epithelium. Aims We aimed to investigate whether the WOS is visualized in the duodenum after exogenous fat loading (FL) administration in an open-label, randomized, controlled study. Methods The patients scheduled to undergo endoscopic therapy for gastric epithelial neoplasms were enrolled in the study. They were randomly assigned to the FL or non-FL group. An initial (before FL administration) and follow-up (after two to three weeks) endoscopic examinations were conducted to observe the duodenal mucosa using magnifying narrow-band imaging. Each patient in the FL group consumed 250 ml of Ensure H (R) four hours before the follow-up examination. Two experienced endoscopists determined the grade of the WOS. FL test results were judged positive for patients who showed a higher grade at the follow-up examination than at the initial examination. The rate of positive test results was compared between the two groups. Results Twenty patients (10 in the FL and 10 in the non-FL groups) were included. FL test results were positive for all 10 patients in the FL group, while they were negative for all 10 patients in the non-FL group (P < 0.001 by Fisher's exact test). Conclusions Lipids loaded onto normal duodenal epithelium were absorbed, and the absorbed lipid droplets appeared as WOS on magnifying narrow-band imaging.