(Ultrasound Review) There is a known increase in common bile duct (CBD) caliber with aging and after cholecystectomy. In this prospective study published in the Journal of Ultrasound in Medicine by radiologists at Louisiana State University School of Medicine, ultrasound was used to evaluate the change in CBD diameter in 1,018 patients over 60 years old.
"The goals of this prospective study were first to determine if a significant change occurs in the diameter of the CBD with aging, in particular after the age of 60 years, and second, if a significant change in duct diameter does occur, to determine what the normal size of the common duct is in this patient population," the article states.
The normal range of CBD diameter was established for each year within that age group. None of the patients included had a history of biliary disease or abdominal pain.
The extrahepatic bile duct was measured 2 cm superior to the head of the pancreas. The internal diameter was measured in both the longitudinal and transverse planes, and an average diameter was calculated. No significant difference in diameter was shown comparing the two planes.
Patient preparation was not requested, but all patients were examined at least one hour after a meal. The researchers considered that the state of fasting had a negligible effect on CBD size. It was established that there was a small but statistically significant difference in bile duct diameter in subjects 60 years old (3.6 mm), compared with those 85 years old or older (4 mm).
According to the authors, the established normal limit of 6 mm to 7 mm with 1 mm added for each decade of life is inappropriate. The results of this study demonstrated that "in the overwhelming majority of patients 60 years of age or older, the mean diameter of the CBD remained normal, being less than 6 mm in 98% of patients and less than 7 mm in 99% of the patients we surveyed."
Robert S Perret et al
Dept of Radiology, Louisiana State University School of Medicine in New Orleans
1532 Tulane Ave, New Orleans, LA 70112, USA
J Ultrasound Med 2000; 19:727–730
By Ultrasound Review
January 19, 2001
Click here to post your comments about this story. Please include the headline of the article in your message.
Copyright © 2001 AuntMinnie.com
