THE NORMAL RETROGRADE CHOLANGIOGRAM - A DEFINITION OF NORMAL CALIBER

Purpose: To evaluate normal retrograde cholangiograms to determine a n ormal range of ductal calibers and identify its variation with age. Ma terials and methods: The retrograde cholangiograms of 136 patients (ag e range: 17-84 years; mean age 49.8 years +/- 17.3 [standard deviation ]) with clinical followup and subsequent studies suggesting normal bil iary trees were evaluated, Patients with previous cholecystectomy, cho ledocholithiasis, or pancreatitis were excluded. Common bile duct (CBD ) and common hepatic duct (CHD) sizes were measured. Results: Measurem ents 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 m m +/- 2.6 mm. There was an increase in CBD caliber by 0.5 mm per decad e of increasing age (p < 0.001) and an increase in CHD caliber by 0.35 mm per decade of age (p < 0.01). Conclusion: The range of normal chol angiographic bile duct caliber is wide and a CBD caliber of 13.9 mm oc curs at the top of this range (mean plus two standard deviations), The re is a small but statistically significant trend of ductal dilatation with advancing age.