Normal values of liver elasticity measured by real-time tissue elastography (RTE) in healthy infants and children.

Abstract

To define normal values of liver elasticity measured by real-time tissue elastography (RTE) in healthy infants and children. RTE was performed on 91 children and adolescents by two experienced observers (female, n=43; male, n=48) and in two age groups (0-10years, n=45; 11-20years, n=46). Hepatopathies were excluded clinically by extensive laboratory testing and by ultrasound. RTE provides a histogram from a region of interest (ROI) in the liver representing the degree of stiffness of the liver. The distribution of the colors in the histogram corresponds to organ elasticity. By calculating the mean of stiffness values, a numerical value is expressed in arbitrary units (a.u.) representing the mean elasticity of the liver (MEAN). Additionally, the percentage values of relatively stiffer areas (color coded in blue) in the ROI can be calculated (%AREA). A Mann-Whitney U test was performed for these two parameters according to gender. The reproducibility of these values was determined with an intraclass correlation coefficient (ICC) test on another group of 18 healthy volunteers. The median elasticity was 106a.u. Gender did not have an influence on the parameters (MEAN: p=0.052; %AREA: p=0.051). Age-specific analyses did not yield any significant difference between the two age groups for either of the two analyzed parameters (MEAN: p=0.059; %AREA: p=0.058). The ICC test demonstrated a moderate agreement for MEAN (ICC=0.582) and %AREA (ICC=0.659). Real-time elastography is a new sonography-based method and may be used as a supportive analysis to assess liver parenchyma elasticity in children, especially when fibrosis is suspected. We measured RTE normal values in children as reference data.