Quantitative endoscopy in the chemoprevention of Barrett's Esophagus Trial.

The Chemoprevention for Barrett's Esophagus Trial (CBET) was a phase IIb, multicenter, randomized, placebo-controlled trial of celecoxib in patients with Barrett's esophagus. The overall outcome of the study was that there were no significant differences in primary, secondary, or tertiary outcomes. The purpose of the current study is to focus on results related to the method of measuring lesion size called quantitative endoscopy (QE). The design includes a review of a total number of studies and then restricts analyses to the four clinics that enrolled more than four patients each for whom a baseline and 1-year QE study was performed, comparing intra- and inter-patient and clinic differences in Barrett's esophagus. Measurements include the number of total QEs and adverse events, changes in areas from baseline to 1 year and other intervals, classification of Barrett's lesion type with respect to patients, clinics, and treatment. A total of 309 QE studies were completed with no adverse events. Differences in surface area measurements over time for a particular patient are smaller than the differences for randomly selected patients. The complexity mix (as defined by the mix of circumferential, tongues, and islands) of the Barrett's lesions varied with different clinics. In conclusion, QE is an efficient, safe, and accurate way to measure the area of Barrett's lesions variation between different clinical sites may be attributable to a subtle type of selection bias at the individual clinics rather than to regional differences.

Extent of Barrett's metaplasia: a prospective study of the serial change in area of Barrett's measured by quantitative endoscopic imaging.

BACKGROUND: An accurate determination of the extent of Barrett's metaplasia is critical to the study of its natural history and response to therapy. Our hypothesis is that area calculations offer advantages over length estimates of Barrett's. METHODS: Changes in both measures and estimates of progression or regression between two endoscopies in 17 patients were compared. Area was calculated using a computer image analysis technique. RESULTS: Although there was no significant difference in length correlation versus area correlation between endoscopies (r = 0.90 vs 0.99), the mean change in absolute length (1.4 +/- 0.2 cm) was greater than the change in area (4.5 +/- 1.4 cm2, equivalent to a length of 0.67 +/- 0.2 cm, p = 0.001). The percent change in absolute length (26.9%) was greater than the change in area (16%, p = 0.001). Discordance of estimates of progression or regression between area and length was found in nine patients. The image technique detected no change in the area of squamous islands. CONCLUSIONS: Imaging analysis can precisely measure the extent of Barrett's including squamous islands. Area showed little change, whereas measures of length were more varied. Computer based image analysis provides a more precise estimate of interval change of Barrett's.

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.