Use of hepatobiliary scintigraphy in the diagnosis of extrahepatic biliary obstruction in dogs and cats: 25 cases (1982-1989).

Twenty-five animals (21 dogs and 4 cats) in which hepatobiliary scintigraphy (HBS) was performed between 1982 and 1989 were included in a retrospective study to determine the utility of HBS for diagnosis of extrahepatic biliary obstruction. Final diagnoses, which were based on liver biopsy results and surgical findings in all animals, were hepatocellular disease alone (n = 17), hepatocellular disease and extrahepatic biliary obstruction (n = 7), and normal liver (n = 1). Hepatobiliary scintigraphy was performed by use of 99mTc-diisopropyl iminodiacetic acid in all cases. All 7 cases of extrahepatic biliary obstruction were confirmed at surgery. In animals with biliary obstruction, HBS failed to demonstrate radiolabel within either the gallbladder or intestine at any time. Using nonvisualization of the intestine by 180 minutes as the scintigraphic criterion for diagnosis of biliary obstruction, sensitivity was 83% and specificity was 94% in this series. Hepatobiliary scintigraphy was concluded to be an accurate indicator of extrahepatic biliary obstruction in this group of animals. High serum bilirubin concentration at the time HBS was performed did not appear to reduce the diagnostic usefulness of the scintigraphic findings.