We wish to study patients with liver cirrhosis during and 2 weeks after an acute episode of liver coma (hepatic encephalopathy). By means of Positron Emission Tomography we investigate; brain blood flow, brain ammonia uptake and brain oxygen consumption. We hypothesize that blood flow an oxygen consumption is diminished and ammonia uptake increased during an acute episode of hepatic encephalopathy.

Inclusion Criteria:

• patients with an acute episode of hepatic encephalopathy

Exclusion Criteria:

• previous stroke

patients with hepatic encephalopathy