Detection of dysplasia at colonoscopy using laser-induced fluorescence: a blinded study☆,☆☆,★,★★

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Abstract

Background: Laser-induced fluorescence spectroscopy has the potential to detect colonic dysplasia in vivo. However, previous studies have limited their analyses to multivariate regression techniques and unblinded retrospective evaluation. The purpose of this study was to develop a probability-based algorithm to detect colonic dysplasia using laser-induced fluorescence spectroscopy and to evaluate it in a blinded manner. Methods: Fluorescence spectra were collected from normal mucosa and colonic polyps during colonoscopy using 370 nm excitation. Tissue was classified as normal, hyperplastic, or adenomatous by histologic examination. Preliminary data was used to devise an algorithm to differentiate tissue type based on probability distributions of the fluorescence intensity at 460 nm and the ratio of the intensity at 680 nm to that at 600 nm. The algorithm was then tested in a blinded fashion. Results: The algorithm correctly determined the tissue type in 88% of cases, equal to the agreement of independent pathologists. Sensitivity, specificity, and positive predictive value for the detection of dysplasia was 90%, 95%, and 90%, respectively. Conclusions: Dysplasia was detected in vivo using fluorescence spectroscopy and a probability-based algorithm. This method may form the basis for a new surveillance technique for patients with increased risk for dysplastic transformation. (Gastrointest Endosc 1996;44:168-76.)

Section snippets

METHODS

During a 14-month period, adult patients of either gender referred for colonoscopic removal of previously identified polyps or for surveillance colonoscopy because of a history of adenomatous polyps were invited to participate in the study. The study protocol was approved by the Institutional Review Board of The Cleveland Clinic Foundation and The Committee on Use of Humans as Experimental Subjects of the Massachusetts Institute of Technology. Informed consent was obtained from each patient

RESULTS

Fluorescence emission spectra were collected from 103 polypoid and 104 endoscopically normal-appearing mucosal sites in the colons of 57 patients (38 men, 19 women). Data from several polyps were eliminated because melanosis coli (2), intramucosal adenocarcinoma (1), ganglioneuroma (1), or lipoma (1) was detected on histologic examination, or histologic diagnosis was impossible because of electrocautery artifact or an absence of sufficient tissue (4). Benign lymphoid aggregates (5), which

DISCUSSION

This study evaluated the accuracy of laser-induced fluorescence spectroscopy for the detection of gastrointestinal dysplasia in patients with colonic polyps. Two spectral regions containing specific information were identified, each of these being described by a pair of parameters. From an analysis of the probability distributions of these parameters, a decision algorithm was constructed that could easily be visualized. This approach forms the basis of a method that detects colonic dysplasia

Acknowledgements

The authors thank Michael Feldstein, Irving Itzkan, and George Zonios for helpful discussions.

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    From the Departments of Biomedical Engineering, Gastroenterology, and Anatomic Pathology, The Cleveland Clinic Foundation, Cleveland, Ohio, the Division of Gastroenterology and the Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, and the Laser Biomedical Research Center, George R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts.

    ☆☆

    This work was supported by the National Institutes of Health grant #CA53717, and #RR02594 through the administration of the MIT Laser Biomedical Research Center. The authors also gratefully acknowledge a generous educational grant from Albert Reidy, Chairman, Wilmington Arena Authority, which supports in part Dr. Van Dam's efforts.

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    Reprint requests: Robert Cothren, PhD, Biomedical Engineering/Wb3, The Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, OH 44195.

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    37/1/71051.

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    Copyright © 1996 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.