Cerebral metabolic changes in cirrhotic patients before and after liver transplantation: a MR spectroscopy study

Abstract

Objective To quantitatively evaluate the metabolic changes in posterior cingulated cortex and left basal ganglia in patients with liver cirrhosis before and after liver Transplantation (LT).Methods A total of 22 controls and 37 cirrhotic patients listed for LT were enrolled in the study. Brain MRS (PRESS sequence) and neuropsychological (NP) tests were performed in all subjects. Eighteen patients were followed up at 1 month and 3 month after LT. The NP parameters including number connection test-A ( NCT-A), digital symbol test (DST) and symbol digital test (SDT) were measured. MRS metabolic contents were measured automatically at posterior cingulate cortex (PCC) and left basal ganglia (LBG).Independent t-test was used to compare the parameters of NP test and MRS metabolites between the 2 groups. The changes of the parameters before and after LT were compared using analysis of variance.Pearson correlation test was also used to analysis the relationship between NP test parameters and MRS metabolites. Results ( 1 ) Before LT, significant difference of metabolites was found in the PCC between the two groups [ NAA/Cr(1.96 ±0.21, 1.73 ±0. 12), Cho/Cr(0. 65 ±0. 12,0. 83 ±0.09), mI/Cr (0.41 ±0.14,0.72±0.11), Glx/Cr(2. 37 ±0. 38,1. 92 ±0. 32) (t= -5.42,5.96,8.62,-4.72,P＜0.01)].And statistical significance also were found in LBG between the 2 groups [ Cho/Cr (0. 63 ± 0. 16,0. 77 ±0. 10), mI/Cr(0.38 ±0. 17,0.53 ±0.21), GIx/Cr(1.70 ±0.36,1.29 ±0.30), (t =3.64,3.07,-4.58 ,P ＜ 0. 01 )]. (2)Compared with controls, the patients before LT had longer NCT-A reaction time [ (58. 17 ±19. 12) s,(37.68 ±8.02) s,t =4. 14,P＜0.01], lower scores of DST (36.67 ±9.91,55.36 ±9.27,t = 4.60,P＜0.01) and SDT (31.67 ±9.49,50.73 ±8.34,t = 4.652,P＜0.01) before LT. All the scores of NP tests changed significantly at 1 and 3 month after LT compared with those before LT[ NCT-A (53.06±12.71) s,(35.72 ±5.20) s,F =33.554,P ＜0.01 ], DST(41.89 ±8. 17,54.39 ±5.69,F =85.772,P＜0.01),SDT(37.44±7.68,49.39±5.65,F=83.061,P＜0.01)]. (3) In the 18 patients who were followed, Cho/Cr [ PCC (0. 90 ± 0. 14,0. 92 ± 0. 08, F = 38. 178, P ＜ 0. 01 ); LBG (0. 81 ± 0. 08,0. 80 ±0.09,F =9.447,P ＜0.01)] and Glx/Cr [ PCC(1.86 ±0.32,1.75 ±0.25,F = 19.420, P ＜0. 01 ); LBG( 1.30 ±0. 20,1.23 ±0. 25 ,F = 17. 952,P ＜0. 01 ) ] recovered at 1 month after LT, while the mI/Cr [PCC (0.39±0.15,0.71 ±0. 10,F =75. 186,P＜0.01) ;LBG (0.47 ±0.25,0.61 ±0.27,F =8. 027, P ＜ 0. 01 ) ] recovered at 3 month after LT. (4)mI/Cr of cingulate cortex correlated significantly with NCT-A, DST and SDT (r= -0.743, 0.597, 0.615, P＜0.01 ) before LT. Conclusion Cerebral metabolic changes in patients with liver cirrhosis is reversible and MRS of the posterior cingulate cortex is a helpful method in following up the changes after LT. mI/Cr is a useful indicator to predict the brain changes of cirrhotic patients before and after LT. Key words: Hepatic encephalopathy; Liver transplantation; Magnetic resonance spectroscopy