Portasystemic shunt fraction quantification using transrectal administration of iodine-123 iodoamphetamine in dogs with chronic bile duct ligation and after propranolol administration.

Following transrectal administration, 123I iodoamphetamine (IMP) has been shown in both animal and patient studies to be capable of detecting the presence of portasystemic shunting (PSS). However, the ability of this method to actually quantitate PSS in the presence of cirrhosis and propranolol has not been demonstrated. We studied nine dogs with hitologically proven cirrhosis induced by chronic bile duct ligation. After intravenous injection of propranolol, PSS were measured with both the IMP method and the standard of portal vein infusion of 99mTc macroaggregated albumin (MAA) given through a mesenteric vein catheter. Based on linear regression, a close relationship was seen, given by the equation: MAA = IMP 0.9 + 0.035, with correlation coefficient of 0.99. Thus, in dogs with cirrhosis secondary to chronic bile duct ligation and after propranolol administration, PSS can be quantitated with the transrectal IMP method.