Optical biopsy of GI lesions by reflectance-type laser-scanning confocal microscopy

Background: Laser-scanning confocal microscopy (LCM) is a new, noninvasive method of optical imaging that may be able to provide an instant microscopic image of untreated tissue under endoscopy. Objective: The aim of this study was to compare LCM images and histologic images of GI lesions to clarify the usefulness of LCM in diagnosing neoplastic lesions. Design: This study was a feasibility study. Setting: The Department of Endoscopy, Hiroshima University Hospital. Patients and Main Outcome Measurements: The study materials were GI lesions resected endoscopically at our institute. Twenty-two areas of 15 untreated specimens from the esophagus (normal mucosa, n = 1; dysplasia, n = 1), stomach (normal mucosa, n = 3; cancer, n = 5), and colon (normal mucosa, n = 3; adenoma, n = 8; cancer, n = 1) were examined. LCM images and images of hematoxylin and eosin-stained sections were compared. A prototype probe LCM system that is equipped with a semiconductor laser that oscillates at 685 nm and that analyzes reflected light was used. Results: Smooth nuclei of cells were visualized by LCM in the normal esophageal-mucosa specimen. Irregular nuclei were visualized in 3 of 5 gastric-cancer specimens and in cells around the crypt of the colonic-cancer specimen. Nuclei were visualized in 5 of 8 colonic-adenoma specimens. Nuclei were not visualized in 2 of 3 normal gastric-mucosa specimens or in normal colonic-mucosa specimens. Conclusions: LCM provides instant microscopic images, and, with further technical improvement, in the future this novel method will aid in immediate diagnosis under endoscopy without the need for tissue biopsy.