Minimal hepatic encephalopathy in children: evaluation with proton MR spectroscopy

Abstract

Background and purpose: Minimal hepatic encephalopathy (MHE) in children is difficult to evaluate because of lack of standardized neuropsychological tests for all age ranges. The purpose of this retrospective study of children with clinically suspected MHE was to investigate relationships between brain MR spectroscopy metabolites and biochemical markers of encephalopathy as well as measures of liver disease severity.

Materials and methods: A total of 12 children (age range, 9-19 years; 8 female) with clinically suspected MHE were studied by short TE brain MR spectroscopy on a 1.5T magnet. We estimated gray matter (GM) and white matter (WM) metabolite concentrations using "LCModel" software. Regional metabolite concentrations were examined for correlation with various parameters, including plasma ammonia, the ratio of branched-chain to aromatic amino acids (BCAA/AAA), model for end stage liver disease/pediatric end stage liver disease (MELD/PELD) and Child-Pugh scores, bilirubin, albumin, and platelet counts.

Results: Myo-inositol (mIns) levels correlated with BCAA/AAA ratios (r = 0.86; P = .002 for GM and r = 0.77; P = .01 for WM). WM choline (Cho) levels and GM mIns levels showed significant negative correlation with ammonia levels (r = -0.58; P = .04 and r = -0.65; P = .02, respectively). A positive significant correlation trend was present for GM glutamine/glutamate (Glx) and ammonia levels (r = 0.66; P = .05). There was no correlation of brain MR spectroscopy parameters and severity of liver disease.

Conclusions: Brain MR spectroscopy metabolites in children with suspected MHE show significant correlations with plasma ammonia levels and BCAA/AAA. As in adults, brain MR spectroscopy in children may be helpful in establishing a diagnosis of MHE.

Figures

Fig 1.

2 × 2 × 2-cm voxel locations used for MR spectroscopy in the medial occipital GM and left parietal WM, overlaid on T2-weighted MR imaging.

Fig 2.

Examples of GM and WM spectra from one subject. Asp indicates aspartyl resonances of free aspartate and NAA.