COMMON BILE-DUCT IN CHILDREN - SONOGRAPHIC DIMENSIONS

PURPOSE: To determine the normal caliber and rate of growth of the ext rahepatic biliary ducts in the pediatric population. MATERIALS AND MET HODS: The diameter of the common bile duct was measured with sonograph y in 173 children aged 1 day to 13 years (mean, 6.0 years; median, 5.0 years) who were examined for reasons other than hepatic or biliary tr act disease. Results were subjected to regression analysis and compare d with similar measurements of the extrahepatic portal vein and hepati c artery. The size of the gallbladder was subjectively estimated as di stended, moderately full, and contracted. Differences in the diameter of the common bile duct in these three groups were evaluated with the Mann-Whitney U test. RESULTS: The average diameter of the common bile duct in this population was 1.27 mm +/- 0.67 (<3.3 mm in all patients and <1.2 mm in children aged 3 months or less). The slope of the curve describing the growth of the common bile duct was relatively flat, si milar to that of the hepatic artery and half that of the portal vein. There was a significant difference in the diameter of the common bile duct between patients with distended gallbladders and those with contr acted gallbladder (P = .02). CONCLUSION: The pediatric common bile duc t is significantly smaller than adult norms; it is a distensible struc ture responsive to fluctuations in prandial bile flow.