Amplitude of low frequency fluctuations abnormalities in liver cirrhosis patients before and after liver transplantation: a resting-state fMRI study

Abstract

Objective To investigate regional activity abnormalities of patients with liver cirrhosis before and after liver transplantation using resting-state fMRI and amplitude of low frequency fluctuations(ALFF) method. Methods Totally 11 patients preparing to accept liver transplantation were adopted into liver cirrhosis group and 11 healthy volunteers in the health examination were adopted into the control group.The liver cirrhosis group was investigated at a week before operation and repeatedly a month after liver transplantation.Healthy volunteers were investigated at the same time.MR imaging data were obtained from a Philips Achieva 1.5-T MR imager.The imaging data were mainly preprocessed with a MATLAB toolbox called DPARSF.REST software was used to calculate the ALFF value of each subject.A second-level random-effect two-sample t-test was performed on the individual ALFF.Significant differences were set at the standard of a corrected cluster level of P<0.05, and software Xjview 8.1 was adopted to express the outcome. Results (1)Compared with control group, decreased ALFF were found in bilateral middle occipital gyrus(MOG)(MNI: x=36, y=-72, z=9), bilateral precuneus/cuneus(PCu/Cu)/posterior cingulated(PCC)(MNI: x=15, y=-66, z=24), left inferior parietal lobule(LIPL)(MNI: x=-39, y=-54, z=42), and bilateral paracentral lobule/cingulate gyrus(MNI: x=3, y=-36, z=45) of cirrhosis patients, no increased ALFF were found.(2)Compared with cirrhosis patients, no increased or decreased ALFF were found in postoperative group.After relaxing standards of statistics, increased ALFF were found in left inferior parietal lobule(IPL)(MNI: x=-39, y=-51, z=42), cingulate gyrus(MNI: x=3, y=-33, z=42), and right middle frontal gyrus(MNI: x=35, y=57, z=0) of postoperative group, no decreased ALFF were found.(3)Compared with control group, decreased ALFF were found in bilateral precuneus/posterior cingulated(PCC), and left middle occipital gyrus (MOG) of postoperative group, no increased ALFF were found. Conclusions Significant decreased ALFF is found in visual cortex(PCu), DMN((PCu/Cu/PCC), and LIPL of cirrrhosis patients, and those abnormalities reflect the weakness of local neurons spontaneous low-frequency.Compared with beforeoperative group, ALFF of LIPL, in cingulate gyrus, and right middle frontal gyrus have a tendency of rising.One month after liver transplantation, decreased ALFF is found in BA7 and BA 31, suggesting that the spontaneous low-frequency of local neurons haven’t recoverd to normal level. Key words: Cirrhosis; Resting-state Functional magnetic resonance imaging; Low frequency fluctuations; Liver transplantation