Using Rest State FMRI Study Pattern Of Resting State Brain Mapping Of Liver Cirrhotic Patients Without Overt Hepatic Encephalopathy Before And After Liver Transplantation

Objective:To study the pattern of resting state functional brain mapping in patients of liver cirrhosis without overt hepatic encephalopathy which includes simple liver cirrhosis and minimal hepatic encephalopathy and short-time shift pattern in patients of cirrhotic patients without overt hepatic encephalopathy after liver transplantation using resting-fMRI.Objects and methods:For all the enrolled patients listed for liver transplantation in this study, liver cirrhosis was diagnosed by liver function test, ultrasonic inspection, imageology and (or) biopsy. There are 28 patients of liver cirrhosis,13 patients of minimal hepatic encephalopathy and 14 patients of simple liver cirrhosis.11 patients repeated the examination 1 month after liver transplantation.30 healthy volunteers with matched age, gender and education was enrolled as controls.MR sequences included routine sagittal T1WI and axial T1WI,T2WI,FLAIR, high resolution anatomical 3D brain GRE T1WI and functional BOLD-EPI data. Parameters of EPI sequences:TR/TE=3000/30ms,flip angle=90°,thickness=4.0mm,gap=1.0mm, FOV= 220mm×220 mm,matrix=64×64,gathered 140 volumes,total scanning time is 7.08 minutes. fMRI data was processed with SPM5 preprocessing modules(slice timing, motion correction, spatial normalization and smoothing).ALFF, FALFF and ReHo maps were calculated with rsfMRI toolkit. General linear model based ANOVA and paired t test were used to find difference between different groups of patients before surgery and paired patients pre-and post-liver transplantation. All subjects performed neuropsychology tests after MR examination.Results:1.there are typical resting state default mode network in ALFF, FALFF and ReHo maps. Functional activities of normal controls, simple cirrhosis and minimal hepatic encephalopathy were observed from ALFF maps with reduced power and number of voxels.Although functional activities of simple liver cirrhosis patients and minimal hepatic encephalopathy patients were reduced compared with normal controls from FALFF and ReHo maps, the pattern is roughly the same between these two entities. 2.Compared with normal controls, non-overt-hepatic encephalopathy patients showed elevated activities of bilateral frontal, temporal lobes and anterior cingulate and reduced activities of bilateral occipital parietal lobe and posterior cingulate. Diffuse elevated activities of bilateral frontal, temporal, parietal and occipital lobes on FALFF and ReHo maps, which are obviously larger area than the reduced activities area, indicate the elevated pattern of patient with liver cirrhosis.3.Compared with simple cirrhosis patients and MHE patients showed no obvious pattern of difference on ALFF maps.There are more elevated area of activities than reduced activities of bilateral frontal, temporal, parietal and occipital lobes on the FALFF and ReHo maps.4. Compared with pre-operative patients, there are reduced activities of bilateral frontal-temporal lobes and bilateral parietal-occipital lobes of 1 month post-operative patients on ALFF maps and reduced activities of all lobes of 1 month post-operative patients on FALFF and ReHo maps.Activity pattern of resting state fMRI of post-LT patients is shifting to the normal state.5.Compared with pre-operation, neuropsychological tests of patients 1 month after LT revealed prolonged NCT test without statistical significance(t=-1.376,p=0.897) and reduced DST/SDC score with statistical significance(t=3.003,p=0.009,t=3.108, p=0.007)Conclusion:1.Simple cirrhosis and minimal hepatic encephalopathy patients shows reduced activities of the default mode networks from the point of energy (ALFF FALFF maps) and regional connections (ReHo maps).2.ALFF is contaminated by perfusion of venous blood, cerebrospinal fluid and micro-perfusion and is less sensitive and reliable than FALFF and ReHo.3.Non-OHE liver cirrhosis patients showed elevated activities in contrast to normal controls and MHE patients showed elevated activities in contrast to simple liver cirrhosis patients, which indicate a continuous shift brain activities of normal controls, simple liver cirrhosis patients and MHE patients and Simple liver cirrhosis and MHE patients are in the stage of preclinical OHE.4.1 month after surgery, without evidence of improved neuropsychological scores, resting state brain activities were shifting to the normal state, showing the characteristic tendency of deviation from neuropsychological test, which may mean resting state fMRI is more sensitive than neuropsychological test to detect the functional recovery of CNS functions.