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

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.

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.

This study was a feasibility study.

The Department of Endoscopy, Hiroshima University Hospital.

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.

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.

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.