Structural and functional cerebral impairments in cirrhotic patients with a history of overt hepatic encephalopathy

Objective: Diffuse brain atrophy has been observed in cirrhotic patients and recent reports have revealed the persistence of cognitive impairment after clinical resolution of overt hepatic encephalopathy. We sought to explore the continued influence of overt hepatic encephalopathy on neurological function by measuring brain resting-state inherent connectivity, based on an investigation of structural abnormalities. Methods: Neuropsychological tests and structural and functional magnetic resonance scanning were conducted in 20 healthy controls and 21 cirrhotic patients with a history of overt hepatic encephalopathy. The analysis of voxel-based morphometry and functional connectivity were performed to detect the alterations in brain structure and function, respectively. Results: Patients showed significantly worse performance in neuropsychological tests as compared with controls, despite apparently normal mental status. Analysis of voxel-based morphometry revealed a decrease in gray matter volume primarily in the midline regions, bilateral insular cortex and caudates, left parahippocampal gyrus, and right cerebellum posterior lobe, while the volume of the bilateral thalamus showed an increase. Of these regions, the posterior cingulate cortex with peak atrophy was selected as the origin for the analysis of functional connectivity. Typical patterns of a default mode network were identified in both groups. Decreased functional connectivity was found in the medial prefrontal gyrus, left inferior parietal lobule, and left middle temporal gyrus in the patients. Conclusions: Both functional and structural impairments were evident after apparent recovery from overt hepatic encephalopathy, demonstrating that brain dysfunction induced by hepatic encephalopathy persisted after clinical resolution and provided a basis for further evolution of the disease. (C) 2011 Elsevier Ireland Ltd. All rights reserved.