title: Common bile duct diameter in an asymptomatic population: A magnetic resonance imaging study.
abstract: OBJECTIVE
  To measure the common bile duct (CBD) diameter by magnetic resonance cholangiopancreatography (MRCP) in a large asymptomatic population and analyze its some affecting factors.
  
  
  METHODS
  This study included 862 asymptomatic subjects who underwent MRCP. The CBD diameter was measured at its widest visible portion on regular end-expiration MRCP for all subjects. Among these 862 subjects, 221 volunteers also underwent end-inspiration MRCP to study the effect of respiration on the CBD diameter. The age, sex, respiration, body length, body weight, body mass index (BMI), portal vein diameter (PVD), length of the extrahepatic duct and CBD, cystic junction radial orientation and location were recorded. The subjects were divided into 7 groups according to age. All of the above factors were compared with the CBD diameter on end-expiration MRCP.
  
  
  RESULTS
  Among the 862 subjects, the CBD diameter was 4.13 ± 1.11 mm (range, 1.76-9.45 mm) and was correlated with age (r = 0.484; P < 0.05), with a dilation of 0.033 mm per year. The upper limit of the 95% reference range was 5.95 mm, resulting in a reasonable upper limit of 6 mm for the asymptomatic population. Respiration and other factors, including sex, body length, body weight, BMI, PVD, length of the extrahepatic duct and CBD, cystic junction radial orientation and location, were not related to the CBD diameter.
  
  
  CONCLUSIONS
  We established a reference range for the CBD diameter on MRCP for an asymptomatic population. The CBD diameter is correlated with age. Respiration did not affect the non-dilated CBD diameter.
authors.affiliation: Rong Peng, Ling Zhang, Ze-Ming Zhang, Department of Radiology, Medical Imaging Center, Panzhihua Central Hospital, Panzhihua 617000, Sichuan Province, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Peng
authors.affiliation: Rong Peng, Ling Zhang, Ze-Ming Zhang, Department of Radiology, Medical Imaging Center, Panzhihua Central Hospital, Panzhihua 617000, Sichuan Province, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Rong Peng, Ling Zhang, Ze-Ming Zhang, Department of Radiology, Medical Imaging Center, Panzhihua Central Hospital, Panzhihua 617000, Sichuan Province, China.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Zhang
authors.affiliation: Rong Peng, Ling Zhang, Ze-Ming Zhang, Department of Radiology, Medical Imaging Center, Panzhihua Central Hospital, Panzhihua 617000, Sichuan Province, China.
authors.forename: Tian-Wu
authors.initials: TW
authors.lastname: Chen
authors.affiliation: Rong Peng, Ling Zhang, Ze-Ming Zhang, Department of Radiology, Medical Imaging Center, Panzhihua Central Hospital, Panzhihua 617000, Sichuan Province, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.affiliation: Rong Peng, Ling Zhang, Ze-Ming Zhang, Department of Radiology, Medical Imaging Center, Panzhihua Central Hospital, Panzhihua 617000, Sichuan Province, China.
authors.forename: Xiao-Hua
authors.initials: XH
authors.lastname: Huang
authors.affiliation: Rong Peng, Ling Zhang, Ze-Ming Zhang, Department of Radiology, Medical Imaging Center, Panzhihua Central Hospital, Panzhihua 617000, Sichuan Province, China.
authors.forename: Ze-Ming
authors.initials: ZM
authors.lastname: Zhang
keywords: Adult; Biliary tract; Common bile duct; Magnetic resonance imaging