Magnetic resonance brain imaging, manganese and ammonia changes in chronic liver disease: reversibility post liver transplantation

Abstract

Abstract

Background: In patients with chronic liver disease (CLD), the presence of hepatocellular failure and/or portosystemic shunting lead to structural and functional brain changes. These changes are due to an increase in substances that under normal circumstances, are efficiently metabolized by the liver. These abnormalities can be detected by MRI and magnetic resonance spectroscopy (MRS).

Objectives: This study aims to evaluate changes in MR brain imaging, manganese, and ammonia levels in patients with chronic liver disease. Additionally, to assess the reversibility of these changes post-living donor liver transplantation.

Methods: The study included 10 adult male patients with CLD who underwent LDLT and 10 age and sex-matched healthy control subjects. All patients were subjected to clinical examination, routine labs, MR and MRS examinations of the brain. Follow-up MRI and MRS brain examination, as well as ammonia and manganese levels, were performed 6 to 9 months post-liver transplantation.  

Results: The CHILD score ranged from 7 to 13 with a mean of 10.4 ± 1.8, whereas the MELD score ranged from 12 to 22 with a mean of 17.5 ± 3.4. Ammonia levels pre-transplantation (mean 60 ± 7.8) decreased significantly post-transplantation (mean 45.8 ± 7) (P <0.001). Also, manganese levels pre-transplantation (mean 2.2 ± 0.16 decreased significantly post-transplantation (mean 1.18 ± 0.09) (P <0.001).
Pallidal T1 hyperintense signal was detected in 8 out of 10 patients and regressed in 6 of them post-transplant. Eight patients demonstrated hyperintense whiter matter lesions (WMLs) in FLIAR WI that regressed in all patients after LT (P = 0.011). MRS findings demonstrated lower Cho/Cr and MI/Cr and higher Glx/Cr compared to controls (P < 0.05).

The abnormal brain metabolites returned to normal levels post-transplant. Blood levels of ammonia and manganese significantly decreased post-transplant compared to their pre-transplant levels (P <0.01).
Conclusions: MRI and MRS findings can be used to detect metabolic brain abnormalities in CLD patients with a correlation with ammonia and manganese levels. Moreover, they can be used to monitor the patients post-transplant.