REDUCTION OF INCREASED SIGNAL INTENSITY IN THE BASAL GANGLIA ON T1-WEIGHTED MR IMAGES DURING TREATMENT OF HEPATIC-ENCEPHALOPATHY

A 61-year-old man with liver cirrhosis showed a symmetrical increase i n the signal intensity of the basal ganglia on T1-weighted magnetic re sonance (MR) images, which was diminished after 3 months of treatment for hepatic encephalopathy. He recovered from encephalopathy with trea tment, and liver dysfunction (hyperammonemia and abnormal blood coagul ation) as well as the results of quantitative psychometric tests showe d a marked improvement. The cause of these high signal intensity chang es on T1-weighted images and the reason for their partial reversibilit y are not known, but hyperammonemia due to portal-systemic shunting mi ght be closely related to these clinical observations.