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.

Annular pancreas as a cause of extrahepatic biliary obstruction.

Annular pancreas is a rare congenital abnormality that is increasingly diagnosed by endoscopic retrograde cholangiopancreatography (ERCP) in the adult. In this population, it can present with duodenal or gastric ulceration, duodenal obstruction, pancreatitis, and, rarely, with associated congenital abnormalities. Although it has been suggested that biliary obstruction may result from associated pancreatitis, such cases have not been reported; primary extrahepatic biliary obstruction from a constricting annulus also has not been reported. We report such a case, and describe resolution of symptoms and a return to normal biochemical tests in a patient. The literature and embryology of annular pancreas are reviewed. We suggest that this entity be added to the differential diagnosis of extrahepatic biliary obstruction.