T2* MRI of minimal hepatic encephalopathy and cognitive correlates in vivo

Area of Science:

• Neuroimaging
• Hepatology
• Cognitive Neuroscience

Background:

• Minimal hepatic encephalopathy (MHE) is a subtle form of liver dysfunction affecting cognition.
• Assessing brain iron deposition is crucial for understanding MHE pathophysiology.
• T2*-weighted imaging offers a method to quantify regional brain iron.

Purpose of the Study:

• To evaluate regional brain iron deposition in MHE using T2*-weighted MRI.
• To investigate the relationship between T2* magnetic resonance (MR) changes and cognitive performance in MHE patients.

Main Methods:

• Forty hepatitis-B virus (HBV)-related cirrhotic patients (28 with MHE) and 22 healthy controls underwent 3 Tesla MRI.
• Cognitive function was assessed using Number Connection Test-A (NCT-A), Letter Digit Substitution Test (LDST), and Rey-Osterrieth Complex Figure Test (RCFT).
• Phase values, indicating iron levels, were measured in frontal-basal ganglia-thalamocortical circuits; statistical analyses included Spearman correlation and multiple linear regression.

Main Results:

• MHE patients showed impaired performance on NCT-A, LDST, and RCFT.
• Significantly decreased phase values (iron levels) were observed in the bilateral putamen of MHE patients compared to controls.
• Phase values in the putamen and right frontal white matter correlated significantly with cognitive performance in MHE patients.

Conclusions:

• Reduced iron deposition in the frontal cortical-basal ganglial circuits is an independent factor contributing to cognitive impairment in MHE.
• T2*-weighted MRI can detect regional brain iron alterations associated with MHE.
• These findings highlight the role of iron dysregulation in MHE-related cognitive deficits.