Hepatic encephalopathy due to a large intrahepatic communication between the portal vein and inferior vena cava

A 59 year old man with cirrhosis presented with encephalopathy and hyper-ammonaemia. T1 weighted magnetic resonance imaging demonstrated a large void tubular structure connecting the right posterior portal vein branch and the inferior vena cava through the right hepatic lobe inferiorly, and cine-mode imaging showed a flow within this channel. Clearly in this patient a significant portion of the portal venous blood was being shunted into the inferior vena cava, causing encephalopathy. The exact origin of this channel is not known, but several possibilities are discussed. It is also predicted that similar previously unknown large intrahepatic shunts will be discovered increasingly with the availability of modern imaging techniques.