Noninvasive assessment of portosystemic shunting in extrahepatic portal hypertension in rats.

A simple reproducible animal model of extrahepatic portal hypertension (EHPHT) has been developed in weanling Wistar rats using a two-stage ligation of the portal vein. This model consistently produces substantial collaterals, both portosystemic (hepatofugal) and portoportal (hepatopetal). Using dynamic hepatic scintigraphy (DHS) with 99mTechnetium sulphurcolloid, hepatopetal collateral flow was measured as the mesenteric fraction (MF) of total hepatic blood flow and compared with measurement of hepatofugal collateral flow (portosystemic shunting) following intraportal injection of radiolabeled microspheres. Strong and significant correlation between the two assessments was found with reduction in MF denoting increased portosystemic shunting (PSS). The technique of DHS has been used successfully in adults to assess compromised portal venous flow and is a simple noninvasive test to aid diagnosis, assessment, and follow-up of children with EHPHT.