Magnetic Resonance Elastography Measured Shear Stiffness as a Biomarker of Fibrosis in Pediatric Nonalcoholic Fatty Liver Disease

Abstract

Magnetic Resonance Elastography (MRE) is promising for non-invasive assessment of fibrosis, a major determinant of outcome in nonalcoholic fatty liver disease (NAFLD). However, data in children are limited. Study aims were to determine accuracy of MRE for detection of fibrosis and advanced fibrosis in children with NAFLD, and to assess agreement between manual and novel automated reading methods. We performed a prospective, multi-center study of 2D-MRE in children with NAFLD. MR-elastograms were analyzed manually at 2 reading centers and using a new automated technique. Analysis using each approach was done independently. Correlations were determined between MRE analysis methods and fibrosis stage. Thresholds for classifying the presence of fibrosis and of advanced fibrosis were computed and cross-validated. In 90 children with mean age of 13.1 ± 2.4 years, median hepatic stiffness was 2.35 kPa. Stiffness values derived by each reading center were strongly correlated with each other (r=0.83). All three analyses were significantly correlated with fibrosis stage (center 1, ρ=0.53; center 2, ρ=0.55; and automated analysis, ρ=0.52; p<0.001). Overall cross-validated accuracy for detecting any fibrosis was the same for all methods: 72.2% (61.8 – 81.1). Overall cross-validated accuracy for assessing advanced fibrosis varied by method: 88.9% (80.5% - 94.5%) for center 1, 90.0% (81.9% – 95.3%) for center 2, and 86.7% (77.9 – 92.9) for automated analysis. Conclusions: 2D-MRE can estimate hepatic stiffness in children with NAFLD. Further refinement and validation of automated analysis techniques will be an important step in standardizing MRE. How to best integrate MRE into clinical protocols for the assessment of NAFLD in children will need prospective evaluation. This article is protected by copyright. All rights reserved.

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