Changed default mode network functional connectivity one month after liver transplantation / 中华放射学杂志

ABSTRACT

Objective To investigate the short?term functional connectivity (FC) changes of default mode network (DMN) after liver transplantation (LT) by using seed?based functional connectivity analysis of resting?state functional MRI (rs?fMRI). Methods Eighteen cirrhotic patients as transplant candidates and 20 healthy controls were included in this study. All the patients underwent rs?fMRI examination before and one month after LT. The data were analyzed using DPARSF and REST software. Seed?based functional connectivity analysis was used to isolate the DMN. The posterior cingulate cortex (PCC) was chosen as seed region for the DMN map. Maps of the DMN were compared among the groups. Values of Z reflecting the functional connectivity of 3 groups were obtained. Two?sample t?test was performed to explore the DMN difference between cirrhotic patients and controls, and we used paired t tests to examine for any differences in functional connectivity before and after LT. Pearson correlation analysis was performed to explore the relationship between the changes of functional connectivity with that of clinical indexes and neuropsychological test scores pre?and post?LT. Results Typically spatial distributions of the DMN were found in all the groups. According to paired t test, post?LT patients showed increased FC in left medial prefrontal cortex (t=3.31, P<0.05), while decreased FC in left precuneus and left lateral temporal cortex (t=-3.37,-4.53,respectively, both P<0.05). Compared to healthy controls, pre?LT patients showed decreased FC in the right precuneus, bilateral medial prefrontal cortex, bilateral inferior parietal cortex, and bilateral lateral temporal cortex(t=-4.32—3.00, all P<0.05), and post?LT patients showed decreased FC in right precuneus, left posterior cingulate cortex, bilateral inferior parietal cortex, and bilateral lateral temporal cortex(t=-4.33—2.99,all P<0.05). Pearson correlation analysis revealed positively correlation between the changes of functional connectivity in left medial prefrontal cortex with that of DST (r=0.543, P=0.02). Conclusions This study found that the DMN FC of post?LT patients still lower than that of healthy controls one month after LT. The left medial prefrontal cortex was the first brain region that showed increased FC, while the FC of some regions continued to decrease, suggesting that brain function reorganization can continue after LT. Rs?fMRI can be used to observe the DMN changes in post?LT patients.