In acute hepatic encephalopathy, also known as acute hyperammonemic encephalopathy or portosystemic encephalopathy, there are usually abnormal signal and diffusion restrictions involving both thalami, insular regions, posterior limbs of internal capsule, cingulate gyrus and diffuse cortical involvement in severe cases with typical sparing of the occipital lobes and perirolandic cortices.

While in chronic hepatic disease, there are usually bilateral hyperintensities of the globus pallidus, subthalamic regions, and midbrain on T1-weighted images

Differential diagnosis of gyriform diffusion restriction include:

• hemodynamic alteration: hypoxic-ischemic insult or post-ictal
• metabolic causes: hypoglycemia or hyperammonemia
• infections: herpes encephalitis, Creutzfeldt Jakob disease or cerebritis