title: The normal retrograde cholangiogram: a definition of normal caliber.
abstract: OBJECTIVE
  To evaluate normal retrograde cholangiograms to determine a normal range of ductal calibers and identify its variation with age.
  
  
  METHODS
  The retrograde cholangiograms of 136 patients (age range: 17-84 years; mean age 49.8 years +/- 17.3 [standard deviation]) with clinical follow-up and subsequent studies suggesting normal biliary trees were evaluated. Patients with previous cholecystectomy, choledocholithiasis, or pancreatitis were excluded. Common bile duct (CBD) and common hepatic duct (CHD) sizes were measured.
  
  
  RESULTS
  Measurements uncorrected for radiographic magnification of CBD revealed a mean of 8.5 mm +/- 2.7 mm [standard deviation] and CHD had a mean of 8.1 mm +/- 2.6 mm. There was an increase in CBD caliber by 0.5 mm per decade of increasing age (p < 0.001) and an increase in CHD caliber by 0.35 mm per decade of age (p < 0.01).
  
  
  CONCLUSIONS
  The range of normal cholangiographic bile duct caliber is wide and a CBD caliber of 13.9 mm occurs at the top of this range (mean plus two standard deviations). There is a small but statistically significant trend of ductal dilatation with advancing age.
authors.affiliation: Radiology Department, Sir Charles Gairdner Hospital, Verdun Street, Nedlands, Western Australia, Australia.
authors.forename: V H
authors.initials: VH
authors.lastname: Low
mesh_terms: D000375:Aging / Q000473:pathology; D002758:Cholangiography; D002760:Cholangiopancreatography, Endoscopic Retrograde; D003135:Common Bile Duct / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D005260:Female; D006500:Hepatic Duct, Common / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values