MR imaging and H-1 spectroscopy of brain metabolites in hepatic encephalopathy: Time-course of renormalization after liver transplantation

PURPOSE: To evaluate changes in hydrogen 1 magnetic resonance (MR) spectros copic findings in overt or subclinical hepatic encephalopathy (HE) after li ver transplantation and to compare these changes with clinical outcomes and basal ganglia high signal intensity (BGH). MATERIALS AND METHODS: Twenty-two patients scheduled for liver transplantat ion and 17 healthy control subjects were examined with H-1 MR spectroscopy and standard nonenhanced MR imaging. Eight patients underwent complete MR i maging and H-1 spectroscopic examinations before liver transplantation and at 3-4-week, 12-28-week, and 10-12-month follow-up after liver transplantat ion. RESULTS: Before liver transplantation, typical 1H spectroscopic changes-dec reased myo-inositol (ml)/creatine (Cr) and choline (Cho)/Cr ratios and an e levated glutamine and glutamate (Glx)/Cr ratio-were found in 21 patients. E ighteen patients had BGH at T1-weighted imaging. Three to 7 months after li ver transplantation, the ml/Cr and Glx/Cr ratios were within the normal ran ge in five of eight and eight of eight patients, respectively, without any residual signs of subclinical or overt HE; however, at MR imaging, seven pa tients still had BGH. CONCLUSION: After successful liver transplantation, renormalization of HE-s pecific brain metabolite changes is detected at H-1 spectroscopy and preced es the disappearance of BCH. The neuropsychologic signs of subclinical or o vert HE follow the changes seen at H-1 spectroscopy rather than those seen at MR imaging.