Clinical Research On Brain Alterations At Brain MRI And ～1H-MRS In Chronic Liver Disease

Objective To study the findings .reason and clinical significance of basal ganglia alterations at brain MRI and !H-MRS in chronic liver disease and role, in the diagnosis and treatment of hepatic encephalopathy.Materials and Methods Brain MRI and 'H-MRS examination were performed in 50 patients (44male and four female patients )with chronic liver disease and 20 healthy volunteers(13male and seven female patients )over a 13 months period between December 2003 and March 2005. MR examination performed on a 1. 5T signa superconducting system (GE company .America) following imaging sequences: transverse fast spin — echo T₂weighted, transverse Tlflair T₁-weighted, coronal or sagittal Tlflair Ti-weighted imaging . 1^H-MRS was detected by single voxel spectroscopy using stimulated echo acquisition mode (STEAM ) sequences (repetition time msec/echo time msec, 2000/30, NEX 128), The volume of interest (VOI) placed in the medial part of the occipital lobe, 2 x 3 x 2-cm³ area contains gray and white matter. All spectra datum were postprocessed by the Functool software . The height of resonance peaks of different metabolites was measured and the rations of other metabolites to Cr were calculated . Signal intensity in Ti-weighted imaging was measured on the globus pallidus(GP) and the frontal white matter (FW), respectively. The equation PI =SI_GP/SIfwX 100% . Besides 5 patients with HE were underwent repetitive MRI and ¹H spectroscopic examinations and 3 of them followed at one months , three months , six months after liver transplantation . Blood manganese and blood ammoniawere measured at less to two day after MR examination . 21 patients have a nonenhancement CT scan . SPSS for 11.0 statistical software package was used to asses the difference of PI and ratio of different metabolites between three groups with contrast group , studied the correlation between pallidal hyperintensity and blood manganese and blood ammonia and Child/Pugh class and metabolites .Results From 50 patients screened, 30(60%)exhibit bilateral symmetric pallidal hyperintensity in Tl-weighted MRI with a normal intensity in T2 , and typically involving the globus pallidus and the substantia nigra . Pallidal hyperintensity was gradually increased fom Chronic Hepatitis patients to Liver Cirrhosis and CHE patients , the differences in PI index between all of them is significant . 1H magnetic resonance spectroscopy shows relative to creatine an increase in glutamine/glutamate (Glx) signal and a decrease of choline containing compounds (Cho) and myo-inositol in patients with cirrhosis or CHE. The Glx signal was more happen to been seen in patients with CHE and the Glx/Cr ratio was higher than that in patients with severe cirrhosis (P<0. 05 = . Blood manganese Child/Pugh grade., mI/Cr Glx/Cr correlated significantly with MRI signal changes respectively. Five to 6 months after successful liver transplantation, pallidal hyperintensity in Tl-weighted MRI was absolutely disappeared and the mI/Cr Cho /Cr Glx/Cr ratios were within the normal range. However, the normalization of ¹H^MRS alterations preceded the disappearance of the globus pallidus hyperintensities.Conclusion Pallidal hyperintensity in Tl-weighted MRI were occur in patients with chronic liver disease or cirrhosis for different reasons and argued for the deposit of manganese which may caused neurodysfunction such as Parkinson syndrome. PI is relative to liver dysfunction as a index of reference . After successful liver transplantation, renormalization of HE-specific brain metabolite changes preceded the disappearance of pallidal hyperintensity. The...