Longitudinal Brain White Matter Alterations in Minimal Hepatic Encephalopathy before and after Liver Transplantation

Abstract

Cerebral edema is the common pathogenic mechanism for cognitive impairment in minimal hepatic encephalopathy. Whether complete reversibility of brain edema, cognitive deficits, and their associated imaging can be achieved after liver transplantation remains an open question. To characterize white matter integrity before and after liver transplantation in patients with minimal hepatic encephalopathy, multiple diffusivity indices acquired via diffusion tensor imaging was applied. Twenty-eight patients and thirty age- and sex-matched healthy volunteers were included. Multiple diffusivity indices were obtained from diffusion tensor images, including mean diffusivity, fractional anisotropy, axial diffusivity and radial diffusivity. The assessment was repeated 6–12 month after transplantation. Differences in white matter integrity between groups, as well as longitudinal changes, were evaluated using tract-based spatial statistical analysis. Correlation analyses were performed to identify first scan before transplantation and interval changes among the neuropsychiatric tests, clinical laboratory tests, and diffusion tensor imaging indices. After transplantation, decreased water diffusivity without fractional anisotropy change indicating reversible cerebral edema was found in the left anterior cingulate, claustrum, postcentral gyrus, and right corpus callosum. However, a progressive decrease in fractional anisotropy and an increase in radial diffusivity suggesting demyelination were noted in temporal lobe. Improved pre-transplantation albumin levels and interval changes were associated with better recoveries of diffusion tensor imaging indices. Improvements in interval diffusion tensor imaging indices in the right postcentral gyrus were correlated with visuospatial function score correction. In conclusion, longitudinal voxel-wise analysis of multiple diffusion tensor imaging indices demonstrated different white matter changes in minimal hepatic encephalopathy patients. Transplantation improved extracellular cerebral edema and the results of associated cognition tests. However, white matter demyelination may advance in temporal lobe.

Screening for minimal hepatic encephalopathy in patients with cirrhosis by cirrhosis-related symptoms and a history of overt hepatic encephalopathy

“…However, the previous studies did not include patients with a history of OHE (23,24). Moreover, OHE and MHE are not fully treated via liver transplantation (19,26), and patients with a history of OHE may experience impaired cognitive function, even subsequent to resolving the OHE (27). Therefore, patients with resolved OHE may be at risk for developing MHE, regardless of the extent of any liver damage.…”

Postoperative cognitive dysfunction after liver transplantation

“…The type cognitive assessment throughout the studies includes several components that are affected in MHE, such as attention, concentration, psychomotor speed and verbal and visuospatial short-term memory. Therefore, most of the studies consider also the persistence or worsening of preexisting cognitive deficits as POCD [27][28][29]22,[37][38][39][40][41][42], in accordance with the statement that successful LT should remove HE [27,31,32]. MHE predicts OHE [43], but it is often clinically missed [44].…”

Liver transplantation significantly improves global functioning and cerebral processing

“…There are also mixed results of incomplete recovery post-transplant using specific brain MRI techniques(4, 7). However, a comprehensive overview of functional brain imaging, neuro-metabolic profile and daily functional assessment in the setting of cognitive recovery is unclear.…”