Measurement of biliary tract size and drainage time. Comparison of endoscopic and intravenous cholangiography.

Measurements of biliary tract size and drainage time were made in 23 patients following endoscopic retrograde cholangiopancreatography (ERCP) and intravenous cholangiography (IVC). The extrahepatic biliary tree appeared approximately 3 mm larger on ERCP than on IVC. Serial measurements of the biliary tree comparing IVC with ERCP are subject to this difference. Comments regarding increasing dilatation of the biliary tree could be erroneous if these differences in technique are ignored. The biliary tract should be free of contrast medium 45 minutes after filling on ERCP; if not, an abnormality may be present at the sphincter of Oddi, even in the absence of other gross radiological biliary tract pathology.