Use of the light-emitting diode-illuminated endoscope for upper gastrointestinal endoscopy.

ting diode (LED)-illuminated endoscopes and previously reported our preliminary experiments with the prototype LED endoscope in the beagle [1]. Authors in Nature noted that the white LEDs we employed have been used for illuminating paintings in fine art museums, as they emit white light with good color rendering and homogeneous light distribution [2, 3]. This supports the notion that these LEDs may also be suitable for use in gastrointestinal endoscopes, as these instruments must be able to indicate subtle changes in the color and mucosal structure of the gastrointestinal tract. The prototype LED endoscopes were based on conventional endoscopes for studies in humans (Fujifilm Corporation, Saitama, Japan), and white LEDs were mounted on their tip (l" Fig. 1). After obtaining Institutional Review Board approval, a patient with an early gastric carcinoma underwent endoscopy using this new endoscope. We found that the white LEDs did not provide sufficient illumination for distant observation in the stomach. However, our prototype LED endoscope allowed clear visualization of the early gastric cancer by close observation. The LED endoscope showed a flat lesion, which was located at the anterior wall of the mid-gastric body and had ill-defined margins accompanied by slightly reddish or focally pale mucosa (l" Fig. 2 a). Indigo carmine chromoendoscopy emphasized the redness of the lesion and delineated the demarcation between the cancerous and non-cancerous mucosa (l" Fig. 2 b). These findings corresponded to those from an examination with a conventional endoscope (l" Fig. 2 c, d). We then subjected the lesion to endoscopic submucosal dissection using a conventional endoscope. Pathological evaluation of the excised tissue revealed that the lesion was an intramucosal differentiated adenocarcinoma and that both its lateral and vertical margins were free of carcinoma cells (l" Fig. 3 a, b). In conclusion, our observations show that our prototype LED-illuminated endoscope can clearly visualize early gastric cancers upon close observation.