Cerebral magnetic resonance imaging in patients with chronic liver disease.

Bilateral, symmetrical hyperintensity of the globus pallidus is observed in T1-weighted cerebral magnetic resonance images in from 52 to 100% of patients with chronic liver disease. No significant relationship exists between the presence of these cerebral changes in image signal intensity and the patients' neuropsychiatric status. However, their presence significantly relates to both the severity of the liver disease and the presence and degree of portal-systemic shunting of blood. This shortening of the T1-relaxation time is associated with pallidal deposition of manganese most likely reflecting the presence of an adaptive process designed to improve the efficacy of ammonia detoxification by astrocytes. Future studies employing magnetic resonance imaging techniques to obtain information on cerebral function or combined with magnetic resonance spectroscopy to obtain localized biochemical information might further our understanding of the pathogenesis of hepatic encephalopathy in cirrhotic patients.