Quantitative endoscopy: precise computerized measurement of metaplastic epithelial surface area in Barrett's esophagus.
BACKGROUND/AIMS: The inability to precisely measure the area of Barrett's metaplasia has impaired the study of its natural history and response to therapy. This study used a novel computer program that creates two-dimensional maps of the esophagus allowing for calculation of the area of Barrett's metaplasia. METHODS: Endoscopic photographs of Barrett's models and patients were obtained by independent endoscopists. The program transformed the photographs into maps, and the area of Barrett's metaplasia was calculated. RESULTS: Using models, calculated areas correlated with actual areas (r = 0.96) with an overall error of 5.2%. Color, size, shape, diameter of the model, or endoscopist's experience did not affect the accuracy. Accuracy did improve by decreasing the interval between photographs from 4 cm (10.0% error) to 2 cm (4.8% error). In patients, area calculations from maps created by independent technicians correlated precisely (r = 0.99) at 1-cm (n = 22) and 2-cm (n = 40) intervals. Independent endoscopists correlated precisely in producing photographs for map construction (r = 0.99; n = 20). CONCLUSIONS: This novel computer technology produces two-dimensional maps of Barrett's metaplasia that can be used to accurately calculate area. Minimal interobserver variability in obtaining photographs is found.