Normal range for MR elastography measured liver stiffness in children without liver disease

BACKGROUND:Magnetic resonance elastography (MRE) can determine the presence and stage of liver fibrosis. Data on normative MRE values, while reported in adults, are limited in children. PURPOSE:To determine the distribution of MRE-measured liver stiffness in children without liver disease. STUDY TYPE:Prospective, observational. POPULATION:Eighty-one healthy children (mean 12.6 ± 2.6 years, range 8-17 years). FIELD STRENGTH/SEQUENCE:3.0T Signa HDxt, General Electric MR Scanner; 2D GRE MRE sequence. ASSESSMENT:History, examination, laboratory evaluation, and (MR) exams (proton density fat fraction, PDFF, and MRE) were performed. MR elastograms were analyzed manually at two reading centers and compared with each other for agreement and with published values in healthy adults and thresholds for fibrosis in adult and pediatric patients. STATISTICAL TESTS:Descriptive statistics, Bland-Altman analysis, t-test to compare hepatic stiffness values with reference standards. RESULTS:Stiffness values obtained at both reading centers were similar, without significant bias (P = 0.362) and with excellent correlation (intraclass correlation coefficient [ICC] = 0.782). Mean hepatic stiffness value for the study population was 2.45 ± 0.35 kPa (95th percentile 3.19 kPa), which was significantly higher than reported values for healthy adult subjects (2.10 ± 0.23 kPa, P < 0.001). In all, 74-85% of subjects had stiffness measurements suggestive of no fibrosis. DATA CONCLUSION:Mean liver stiffness measured with MRE in this cohort was significantly higher than that reported in healthy adults. Despite rigorous screening, some healthy children had stiffness measurements suggestive of liver fibrosis using current published thresholds. Although MRE has the potential to provide noninvasive assessment in patients with suspected hepatic disease, further refinement of this technology will help advance its use as a diagnostic tool for evidence of fibrosis in pediatric populations. LEVEL OF EVIDENCE:1 Technical Efficacy: 5 J. Magn. Reson. Imaging 2019.