High pallidal T1 signal is rarely observed in obstructive jaundice, but is frequently observed in liver cirrhosis.

Although high signal intensities in the globus pallidus are frequently observed in T1-weighted magnetic resonance images (MRI) of patients with liver cirrhosis, it is unclear whether these increases are due to portal-systemic shunt or obstruction of biliary excretion. We therefore studied pallidal signals in 18 cancer patients with bile duct obstruction and marked jaundice (>10 mg/dl). Patients who had fever, leukocytosis or liver cirrhosis were excluded to ensure that jaundice was due to bile duct obstruction. All patients showed a dilated intrahepatic duct on computed tomography (CT) scan. A high pallidal signal was observed in one of 18 biliary obstructive patients whereas high signals were highly prevalent in liver cirrhosis. A portal-systemic shunt rather than an obstruction of biliary excretion may be responsible for the increased blood manganese concentrations and pallidal T1 signals in chronic liver diseases.