Purpose or Case Report: The diagnosis of hepatic encephalopathy is mainly detected by neuropsychological tests. These tests, however, do not always apply depending on the status of the child (age, social and cultural environment) and are therfore not reliable for subtle changes. We propose to detect minimal hepatic encephalopathy (minHE) in children with chronic liver disease and/or porto-systemic shunting, using MRI with Diffusion-weighted (ADC) and ¹H- spectroscopy in the globus pallidum.
Methods & Materials: Our cohort includes 44 patients (mean age:120 months ±58): 14 biliary atresia with Kasai operation, 7 hepatic transplant, 7 portal cavernoma, 4 sclerosing cholangitis, 3 cystic fibrosis, 2 Wilson disease, 2 undeterminate cirrhosis, 1 alpha 1 antitryspsin deficiency, 1 congenital hemochromatosis,1 hemolysis-urémia syndrome,1 Alagille syndrome, 1 tricho-hepato-enteric syndrome. Among them, 8 had a surgical mesenteric-caval shunt at the time of the study and 8 had two MRI.
Fifty-two brain MRI was performed on a 1.5T magnet to examine T1-weighted / ADC images in pallidi. The cho/Cr, mI/Cr, Glx/Cr ratios were calculated and compared with 25 healthy controls. The relation to serum bilirubin, albumin, ammonium and behavioral changes was analyzed.
Results: Among all MR findings only T1-weighted signal (ROI) and mI/Cr ratio in the pallidi differred significantly between patients and healthy controls (p<0.001). MRI of subjects were divided into 3 groups according to the pallidum T1 signal: normal (n=15), grey (n=15), hyperintense (n=22). There was a significant difference in mI/Cr between healthy and T1 hyperintense subjects (p <0.001) and between normal intensity and hyperintense subjects (p=0.02). ADC values did not differ significantly between the three groups. There was no correlation with ammonium, bilirubin or behavioral changes. Serum albumin was lower in the hyperintense group when compared to the grey-signal group (p=0.02)
Conclusions: Children with chronic liver disease and/or porto-systemic shunting present brain MR patterns compatible with minHE. Serum ammonia and bilirubin concentrations are not predictive of these changes and neuropsychological tests may be difficult to interpret. MR findings may explain neurocognitive difficulties observed in these patients. MRI/spectroscopy should be performed in the initial neurological work up followed by adapted psychological tests. Early diagnosis and treatment is essential in the preservation of brain function in the growing child.