What is a key neuroimaging finding in hepatic encephalopathy and what is the typical pathophysiology?

• A. T1 hyperintensity in the basal ganglia (globus pallidus) due to manganese deposition; result of liver dysfunction leading to elevated ammonia
• B. T2 hyperintensity in the hippocampus due to alcohol-related injury
• C. Diffusion restriction in the cortex due to ischemia
• D. No imaging findings are associated with hepatic encephalopathy

Answer: (A)

Hepatic encephalopathy often shows manganese-related signal changes in the basal ganglia on MRI, with the underlying issue being impaired liver function leading to elevated ammonia levels. When the liver fails to detoxify ammonia, it crosses into the brain and astrocytes convert it to glutamine, causing osmotic swelling and disrupted neurotransmission. This hyperammonemia-driven process explains the neuropsychiatric symptoms. The T1 hyperintensity in the globus pallidus is a classic imaging sign in chronic liver disease because manganese, normally cleared by the liver, accumulates in the brain and shortens T1 relaxation, producing that bright signal. Other imaging patterns described—like hippocampal T2 changes from alcohol injury, cortical diffusion restriction from ischemia, or no imaging findings—do not align with the typical imaging hallmark of hepatic encephalopathy.