Preliminary accuracy and interobserver agreement for the detection of intraepithelial neoplasia in Barrett's esophagus with probe-based confocal laser endomicroscopy

Background: Confocal laser endomicroscopy (CLE) is a rapidly emerging method for in vivo imaging of the GI tract. Objective: To determine the preliminary evaluation accuracy and interobserver agreement of probe-based CLE (pCLE) in Barrett's esophagus (BE). Design: Prospective, double-blind review of pCLE images of 40 sites of BE tissue by using matching biopsies as the reference standard. A training set of 20 images with known histology was first reviewed to standardize image interpretation, followed by blinded review of 20 unknown images. Setting: Eleven experts in BE imaging from 4 different endoscopy centers from the United States and Europe evaluated the images. Patients: This study involved nonconsecutive patients undergoing BE surveillance or evaluation of high-grade intraepithelial neoplasia or early adenocarcinoma. Intervention: Intravenous fluorescein pCLE imaging of each site within the BE segment, followed by matching biopsy. Main Outcome Measurements: Sensitivity, specificity, and agreement for the pCLE diagnosis of high-grade intraepithelial neoplasia or carcinoma. Results: In the validation set (n = 20), 11 cases had high-grade intraepithelial neoplasia or invasive carcinoma. The sensitivity for the diagnosis of neoplasia for the 11 endoscopists was 88% (range 6 of 11 to 11 of 11), and the specificity was 96% (range 7 of 9 to 9 of 9). There was substantial agreement on the pCLE diagnosis (86%, kappa 0.72; 95% confidence interval, 0.58-0.86). Endomicroscopists with prior pCLE experience had an overall sensitivity of 91% (all 10 of 11), specificity of 100% (all 9 of 9), and almost perfect agreement (92%, kappa 0.83; 95% confidence interval, 0.64-1.0). Limitations: Small sample size and use of offline video sequences. Conclusion: Results suggest that pCLE for the diagnosis of neoplasia in BE has very high accuracy and reliability.