Identification and diameter assessment of gastric submucosal vessels using infrared electronic endoscopy

In this study, an electronic endoscope was applied for observation of gastric submucosal vessels, with infrared illumination, in anesthetized dogs. An in-vivo spectrophotometry showed that infrared light at 620-820 nm penetrates the abdominal and gastric wall. During the endoscopy performed in dogs, the infrared radiation penetrated the abdominal wall and gastric wall from the outside, and was detected by the endoscope's charge-coupled device. A television monitor displayed a network of gastric vasculature, which was identified as veins in the gastric wall by injecting saline or indocyanine green into the vein. Using this system, it was possible to measure venous diameters of more than 0.2 mm by comparison with a reference wire. The diameter obtained by the image analysis correlated lineally to that of a vascular template prepared from the same stomach. Thus, it may become possible to assess gastric submucosal hemodynamics using infrared endoscopy, a new application in electronic endoscopy.