Intraobserver and interobserver consistency for grading esophagitis with narrow-band imaging.

Background: Narrow-band imaging (NBI) is a novel, noninvasive optical technique that adjusts reflected light to enhance the contrast between the esophageal mucosa and the gastric mucosa. Whether the use of this optical technique may increase consistency in describing the presence and severity of mucosal breaks remains elusive.
Objectives: We compared the intra- and interobserver variations in the endoscopic scoring of esophagitis by using conventional imaging with and without NBI.
Design: Cross-sectional study of consecutive patients with reflux.
Setting: Single center in Taiwan.
Patients: Endoscopic photographs of 230 patients with gastroesophageal reflux were obtained with both methods. Images were randomly displayed twice to 7 endoscopists, who independently scored each photograph by using the Los Angeles classification.
Main Outcome Measurements: We calculated intra- and interobserver kappa statistics to measure the consistency in interpretations.
Results: With the addition of NBI, intraobserver reproducibility significantly improved with 3 of the 7 endoscopists. Interobserver reproducibility was more consistent with the combined approach than with conventional imaging alone, with an improved overall kappa value of 0.62 versus 0.45 (P < .05). Discordance between these methods was substantial in the grading of class A or B esophagitis.
Limitations: A small sample of class D esophagitis might have produced insufficient statistical power in this category.
Conclusions: Intra- and interobserver reproducibilities in grading esophagitis could be improved when NBI was applied with conventional imaging. The benefit appeared to derive from better depictions of small erosive foci.