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® 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.