Enhancing visibility in gastric endoscopic dissection: Red dichromatic imaging in managing submucosal fatty tissue

Abstract

Submucosal fatty tissue can significantly reduce visibility during endoscopic submucosal dissection (ESD) due to lens cloudiness.¹ In colorectal ESD, red dichromatic imaging (RDI) maintains clear visibility in the presence of extensive submucosal fatty tissue.² Despite reports on the effectiveness of RDI in hemostasis during gastric ESD,^{3, 4} evidence and image documentation of its effectiveness in techniques other than endoscopic hemostasis are limited. Therefore, in this video article, we demonstrate the effectiveness of RDI to enhance visibility during gastric ESD.

A 74-year-old man underwent gastric ESD with a therapeutic gastroscope (GIF-H290T; Olympus, Tokyo, Japan). During the circumferential mucosal incision, extensive submucosal fatty tissue was observed. Even after submucosal injection of indigo carmine, the yellow tone of submucosal fatty tissue remained conspicuous under white light imaging (WLI), and the trimming line was obscured. Conversely, RDI suppressed the yellow tone of fatty tissue and emphasized the blue tone of indigo carmine, which allowed for safe trimming. In submucosal dissection, RDI also improved visibility by reducing lens cloudiness, and the submucosal layer was clearly visible (Fig. 1). We achieved en bloc resection without adverse events (Video S1). Pathological examination revealed that all lesions were intramucosal well-differentiated adenocarcinomas with rich adipose tissue in the submucosal layer. As reported previously, RDI can improve the visibility of the submucosal layer during ESD.⁵ RDI reduces the yellow tone of submucosal fatty tissue and they are depicted as the white tone (Fig. 2a–c). Moreover, because RDI does not emit light at shorter wavelengths, it can penetrate greater depths than WLI. Therefore, RDI enhances the blue tone of indigo carmine. Furthermore, the endoscopic appearance with WLI is blurrier because of light scattering than with RDI. (Fig. 2d). In summary, RDI enabled obtaining clear visual fields during gastric ESD with extensive submucosal fatty tissue.

Author M.Y. is Associate Editor of Digestive Endoscopy. The other authors declare no conflict of interest for this article.