Standardization of common bile duct size using ultrasound in pediatric patients.

BACKGROUND/PURPOSE: The incidence of choledocholithiasis is increasing. The diagnosis of common bile duct (CBD) obstruction is based on abnormal CBD size. Establishing norms for CBD size in children would improve diagnostic accuracy. We analyzed ultrasounds (US) to determine normal pediatric CBD size based on age and then validated this against patients with choledocholithiasis.

METHODS

A retrospective review was conducted for children less than 21 years of age with US defined CBD size. Patients were stratified into age groups by ANOVA statistical analysis. Secondary analysis included patients with confirmed choledocholithiasis in comparison to the normal cohort.

RESULTS

A total of 778 patients had US without pathology. Group 1 (<1 year) had a mean CBD of 1.24±0.54 mm, group 2 (1-10 years) 1.97±0.71 mm, and group 3 (>10 years) 2.98±1.17 mm, p<0.05. Fourteen additional patients were found to have choledocholithiasis with a mean CBD size of 8.1 mm. All patients with choledocholithiasis had CBD sizes outside of our normal range, but only 50% of patients had enlarged CBD size based on adult normal range of values.

CONCLUSION

Normal CBD size in children is less than a normal adult patient. More accurate normal values will aid in determining if a child needs further evaluation for possible obstruction of the CBD.

TYPE OF STUDY

diagnostic Level of evidence: III.