From the Guidelines
MRI findings in hepatic encephalopathy typically show changes in the white matter of the temporal lobe, which may persist even after liver transplantation. The diagnosis of cognitive disorders after liver transplantation is challenging, and patients may develop cognitive symptoms even in the absence of these symptoms before transplantation 1. Liver transplantation leads to significant improvement in most cognitive functions in patients with hepatic encephalopathy, although some cognitive functions or radiological signs do not improve as well post-transplant 1. Some key MRI findings in hepatic encephalopathy include:
- Changes in the white matter of the temporal lobe
- Visuomotor deficits
- Cognitive sequelae of hepatic encephalopathy may persist in less than 5% of patients, predominantly patients with grade 3–4 hepatic encephalopathy before liver transplantation 1. The experts suggest that MRI, EEG, and blood ammonia level measurements should be systematically performed to exclude other causes of neurological or neuropsychological impairments that may persist after liver transplantation 1.
From the Research
MRI Findings in Hepatic Encephalopathy
- Typical brain magnetic resonance imaging (MRI) findings of hepatic encephalopathy (HE) include bilateral basal ganglia high signal intensities due to manganese deposition in chronic liver disease and hyperintensity in T2, fluid-attenuated inversion recovery, or diffusion-weighted imaging (DWI) with hemispheric white matter changes including the corticospinal tract 2.
- Low values on apparent diffusion coefficient mapping of the affected area on DWI, indicating cytotoxic edema, can be observed in acute HE 2.
- MRI findings can be correlated with biochemical parameters and EEG alterations in cirrhotic patients without clinically overt encephalopathy, with a significant linear association between EEG grading and MRI signal intensity 3.
- MRI alterations are good predictors of liver and brain dysfunction in cirrhotic patients, with overall Child-Pugh score and albumin levels being significant predictors of the MRI signal intensity 3.
Characteristics of Hepatic Encephalopathy
- Hepatic encephalopathy (HE) is a severe neuropsychiatric abnormality in patients with either acute or chronic liver failure, characterized by a range of neurological and psychiatric abnormalities 2, 4.
- HE can be covert or overt, with covert HE being characterized by mild deficits in psychomotor abilities and overt HE being characterized by more severe neurological impairment, including stupor or coma 4.
- The pathophysiology of HE is complex and involves the accumulation of ammonia and other toxins in the brain, leading to astrocytic swelling and cerebral edema 4.
Diagnosis and Treatment of Hepatic Encephalopathy
- The diagnosis of HE is based on a combination of clinical, laboratory, and imaging findings, including MRI and EEG 2, 3.
- Treatment of HE typically involves a combination of lactulose and rifaximin, with the goal of reducing ammonia levels and improving neurological function 5, 6.
- Rifaximin has been shown to be effective in reducing the risk and duration of hospitalizations for HE, and is generally well-tolerated 6.