Optical effect of spraying l-menthol on gastric intestinal metaplasia visualized by linked color imaging.

ABSTRACT

OBJECTIVE: Linked color imaging (LCI) enables noninvasive detection of gastric intestinal metaplasia (GIM) as a lavender color sign (LCS), and there has been a recent report that l-menthol enhanced GIM with LCI. We measured color values of GIM and surrounding mucosa with white light imaging (WLI), LCI and LCI after spraying l-menthol (Mint-LCI) and investigated the effect of l-menthol on gastric mucosa. METHODS: Endoscopic images of the antrum with WLI, LCI and Mint-LCI from 18 patients were prepared. Each of six regions of interest (three points of GIM and three points of surrounding mucosa) was selected for each modality, and CIE1976 (L*a*b*) color space was used to measure the color values. The primary endpoint was color differences (ΔE) between GIM and surrounding mucosa in each modality. RESULTS: For surrounding mucosa, the mean a* value with Mint-LCI was significantly higher than the mean values with WLI and LCI (P < 0.01). The mean b* value of GIM with LCI was significantly lower than that of surrounding mucosa, and spraying l-menthol decreased the b* values of GIM with a change to a deeper lavender color (LCI 10.0 ± 5.8, Mint-LCI 3.7 ± 6.1, P < 0.01). However, there was no significant difference in mean ΔE values between LCI and Mint LCI (LCI 21.1 ± 6.6, Mint-LCI 22.7 ± 5.4, NS). After spraying l-menthol, the microstructure of GIM changed to translucent and microvessels were obscured. CONCLUSIONS: As shown by LCI, spraying l-menthol optically enhances the color of GIM in the antrum.