Accuracy and interrater reliability for the diagnosis of Barrett's neoplasia among users of a novel, portable high-resolution microendoscope

Abstract

The high-resolution microendoscope (HRME) is a novel imaging modality that may be useful in the surveillance of Barrett's esophagus in low-resource or community-based settings. In order to assess accuracy and interrater reliability of microendoscopists in identifying Barrett's-associated neoplasia using HRME images, we recruited 20 gastroenterologists with no microendoscopic experience and three expert microendoscopists in a large academic hospital in New York City to interpret HRME images. They prospectively reviewed 40 HRME images from 28 consecutive patients undergoing surveillance for metaplasia and low-grade dysplasia and/or evaluation for high-grade dysplasia or cancer. Images were reviewed in a blinded fashion, after a 4-minute training with 11 representative images. All imaged sites were biopsied and interpreted by an expert pathologist. Sensitivity of all endoscopists for identification of high-grade dysplasia or cancer was 0.90 (95% confidence interval [CI]: 0.88-0.92) and specificity was 0.82 (95% CI: 0.79-0.85). Positive and negative predictive values were 0.72 (95% CI: 0.68-0.77) and 0.94 (95% CI: 0.92-0.96), respectively. No significant differences in accuracy were observed between experts and novices (0.90 vs. 0.84). The kappa statistic for all raters was 0.56 (95% CI: 0.54-0.58), and the difference between groups was not significant (0.64 vs. 0.55). These data suggest that gastroenterologists can diagnose Barrett's-related neoplasia on HRME images with high sensitivity and specificity, without the aid of prior microendoscopy experience.

Keywords: cancer; diagnostic imaging; esophagogastroduodenoscopy; optical device.

Figure 1

Schematic diagram of the high-resolution microendoscope (HRME). CCD, charge-coupled device; Cond, condenser lens; Em, emission filter; Ex, excitation filter; LED, light-emitting diode.

Figure 2

Photo of the (a) high-resolution microendoscope (HRME) in a standard size briefcase and the (b) HRME probe inside the accessory channel of a standard endoscope.

Figure 3

High-resolution microendoscope (HRME) image classification criteria of (a) normal squamous mucosa, (b) normal gastric cardia, (c) Barrett's metaplasia, (d) high-grade dysplasia, and (e) adenocarcinoma. Note: The brightness of the image does not correlate with the disease state.

Figure 4

Rater accuracy of classification of Barrett's-related neoplasia high-grade dysplasia (HGD/cancer) versus Barrett's and normal squamous and gastric mucosa. NPV, negative predictive value; PPV, positive predictive value.

Figure 5

Sensitivity and specificity of classification of neoplasia high-grade dysplasia (HGD/cancer) versus non-neoplasia (Barrett's metaplasia, low-grade dysplasia [LGD], normal squamous and gastric mucosa) for each rater.