Structural and functional abnormalities of thalamic subregions in minimal hepatic encephalopathy

The thalamus, which consists of multiple subregions, has been of particular interest in the study of minimal hepatic encephalopathy (MHE). This study aimed to identify abnormalities of the thalamic subregions in patients with MHE and their associations with cognitive performance.

Two groups of patients-30 patients with cirrhosis with MHE (the MHE group) and 48 patients with cirrhosis without MHE (the NHE group)-and 42 healthy controls (the HC group) underwent resting-state functional and structural magnetic resonance imaging. A histologically based atlas was used to segment the thalamus into 25 nuclei and subsequently group the thalamus into 6 subregions. Volume and mean regional homogeneity (mReHo, metrics reflecting local brain activity) were assessed in six thalamic subregions per hemisphere and the entire thalamus, and group differences were analyzed. Correlation analyses were conducted to explore associations between neuroimaging changes and clinical performance.

The MHE group showed increased volume in the bilateral posterior thalamic subregions (false-discovery rate [FDR]-corrected P < 0.05). Functionally, the MHE group showed increased mReHo values in the bilateral posterior, bilateral intralaminar, and left ventral thalamic subregions (FDR-corrected P < 0.05). Notably, both significant structural and functional alterations showed a progressive increase from NHE group to MHE group. These alterations in the thalamic subregions of patients with cirrhosis were significantly correlated with performance on neurocognitive tests (FDR-corrected P < 0.05).

Our findings support the role of thalamic subregional alterations in the pathophysiology of MHE and highlight their potential as neuroimaging markers for early detection of MHE-related cognitive decline.