Brown slits for colorectal adenoma crypts on conventional magnifying endoscopy with narrow band imaging using the X1 system

Figure 1 Representative images of “brown slits” in a low-grade tubular adenoma using conventional magnifying endoscopy. A set of a conventional magnifying endoscope (CF-HQ290Z), X1 system, and 4K 32-inch monitor was used. A, B: Full-zoom (95 ×) magnification, narrow band imaging. Brown slits were observed inside and along the tubular glands surrounded by the microvessels; C: Full-zoom magnifying, white-light imaging observation without indigo carmine spraying showed faint and pale red slits inside and along the tubular glands; D: Full-zoom magnifying, white light imaging with indigo carmine spraying showed indigo carmine accumulated in the site corresponding to the brown slits.