The role of functional magnetic resonance imaging of the brain in the evaluation of hepatic encephalopathy in cirrhotic patients

INTRODUCTION: Hepatic encephalopathy (HE) is a complication of liver failure, with neurological manifestations ranging from minimal HE (MHE) to deep coma (overt HE). AIM OF THE STUDY: To demonstrate the role of functional magnetic resonance imaging (magnetic resonance spectroscopy [MRS] and apparent diffusion coefficient [ADC] value) in the assessment and grading of HE in cirrhotic patients. MATERIAL AND METHODS: A prospective cohort study was conducted on three groups: group I – 20 healthy controls, group II – 25 cirrhotic patients with MHE, and group III – 25 cirrhotic patients with overt HE. Each group was subjected to MRS, diffusion-weighted imaging, and neuropsychological examinations. At (1)H-MRS, the glutamate/glutamine complex (Glx), myo-inositol (mI), choline (Cho), N-acetyl aspartate (NAA), and creatine (Cr) were determined in the basal ganglia or thalamus. The metabolic ratios and ADC values of Glx/Cr, MI/Cr, Cho/Cr, and NAA/Cr were determined. RESULTS: The brain metabolite Glx increased with a significant correlation to HE grade (p = 0.001). Other brain metabolites, such as Cho and mI, decreased significantly (p = 0.001). Two brain metabolites (NAA and Cr) remained unchanged across all HE grades and the control group (p = 0.47 and 0.38, respectively). There was an increase in the Glx/Cr ratio and a decrease in the mI/Cr and Cho/Cr ratios. In addition, ADC values were significantly higher in cirrhotic patients with HE than in the control group. CONCLUSIONS: ADC values and (1)H-MRS are imaging modalities that have the potential to detect MHE and grade HE in cirrhotic patients.