Measurement of common bile duct in healthy children with high-frequency ultrasonography

Objective To measure the diameter of the common bile duct (CBD) in healthy children with different ages using high-frequency ultrasonography. Methods A total of 343 healthy children without any clinical or laboratory evidence for biliary, hepatocellular or pancreatic disease were recruited in this study. Their ages ranged from 1 month to 14 years old (mean age:3.2 years, median age:2.8 years). The diameter of their CBD was determined using realtime high-resolution ultrasonography. Results Among the 343 children, the CBD of 322 were clearly detected and measured (93.9％). The mean CBD diameter of the 322 children was 1.58 ± 0.70 mm. The CBD diameter ranged from 0.4 to 4.4 mm. Multiple linear regression analysis showed the age was the only independent risk factors associated with the diameter of CBD (t =12.494, P＜0.0001 ). Spearman correlation analysis revealed the diameter of CBD was positively correlated with age (r =0.573, P＜0.001). P-P diagrams suggested the diameter of CBD were not normally distributed. Based on these statistic analysis, the reference diameter of CBD in healthy children was less than 2.26 mm in children younger than 1 year old, 2.99 mm in children younger than 4 years old, 3.03 mm in children younger than 7 years old, and 4.10 mm in children younger than 13 years old. Conclusions The diameter of the CBD is increasing with age in healthy children. Key words: Cholangiectasis;  Ultrasonography