Gastroenterology

Gastroenterology

Volume 127, Issue 3, September 2004, Pages 706-713
Gastroenterology

Rapid communication
Confocal laser endoscopy for diagnosing intraepithelial neoplasias and colorectal cancer in vivo

https://doi.org/10.1053/j.gastro.2004.06.050Get rights and content

Background & Aims: Aconfocal laser endoscopy system has recently been developed that may allow subsurface imaging of living cells in colonic tissue in vivo. The aim of the present study was to assess its potential for prediction of histology during screening colonoscopy for colorectal cancer. Methods: Twenty-seven patients underwent colonoscopy with the confocal endoscope using acriflavine hydrochloride or fluorescein sodium with blue laser illumination. Furthermore, 42 patients underwent colonoscopy with this system using fluorescein sodium. Standardized locations and circumscript lesions were examined by confocal imaging before taking biopsy specimens. Confocal images were graded according to cellular and vascular changes and correlated with conventional histology in a prospective and blinded fashion. Results: Acriflavine hydrochloride and fluorescein sodium both yielded high-quality images. Whereas acriflavine hydrochloride strongly labeled the superficial epithelial cells, fluorescein sodium offered deeper imaging into the lamina propria. Fluorescein sodium was thus used for the prospective component of the study in which 13,020 confocal images from 390 different locations were compared with histologic data from 1038 biopsy specimens. Subsurface analysis during confocal laser endoscopy allowed detailed analysis of cellular structures. The presence of neoplastic changes could be predicted with high accuracy (sensitivity, 97.4%; specificity, 99.4%; accuracy, 99.2%). Conclusions: Confocal laser endoscopy is a novel diagnostic tool to analyze living cells during colonoscopy, thereby enabling virtual histology of neoplastic changes with high accuracy. These newly discovered diagnostic possibilities may be of crucial importance in clinical practice and lead to an optimized rapid diagnosis of neoplastic changes during ongoing colonoscopy.

Section snippets

Structure and function of the confocal laser endoscope

Laser scanning confocal microscopy is an adaptation of light microscopy whereby focal laser illumination is combined with pinhole limited detection to geometrically reject out-of-focus light. In single-point scanning confocal microscopes, the point is typically scanned in a raster pattern and measurement of light returning to the detector from successive points is digitized so that an image of the scanned region can be constructed. Importantly, each resultant image is an “optical section”

Comparison of contrast agents

To evaluate the potential of contrast agents for confocal laser endoscopy, 27 patients undergoing routine surveillance screening colonoscopy at the Cabrini Hospital, Australia, between January and September 2003 were recruited for examination. The indications for screening included a personal history of polyps, tumors, or diverticular disease or a family history of colorectal cancer. In all patients examined with the prototype instrument (16 men and 11 women; median age, 63 years; range, 37–77

Discussion

In vivo confocal laser endomicroscopy is a newly developed tool that enables subsurface imaging of living cells in the mucosa during ongoing colonoscopy. The confocal laser microscope was implemented in a conventional video endoscope, which offers the possibility to combine videoendoscopy and confocal microscopy. In the present pilot trial, we report on the use of this confocal laser endoscope in humans to facilitate the prediction of colonic pathology. By directly comparing the results from in

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