False-positive “Cavernous Transformation” Secondary to Lymphatic Filling in Parenchymal Hepatic CO2 Injection for Portal Vein Visualization in TIPS Procedures

During fine-needle CO2 TIPS procedures, what was believed to represent reversed flow of hilar collateral vessels represented hepatic lymphatic vessels. Despite the lack of visualization of the portal vein in nearly one-fifth of patients, targeting of the portal vein was facilitated by the fact the hepatic lymphatic vessels showed a periportal distribution. The high incidence of hepatic lymphatic filling suggestive of cavernous transformation necessitates direct portography or wedged hepatic venography to verify portal vein patency before the procedure is aborted.