Summary: MR elastography (MRE) holds promise for noninvasive liver stiffness monitoring in children and young adults with autoimmune liver disease, with findings indicating strong correlations between MRE liver stiffness measurements and histologic fibrosis scores.

Key Takeways:

  1. The study highlights the potential of MR elastography (MRE) as a noninvasive method for monitoring liver stiffness, particularly valuable for children and young adults with autoimmune liver disease (AILD).
  2. MRE measurements revealed elevated liver stiffness in children and young adults with AILD, emphasizing the significance of noninvasive methods in assessing liver health in this population.
  3. MRE liver stiffness measurements showed strong correlations with histologic fibrosis scores, suggesting its efficacy in assessing liver fibrosis severity, with implications for clinical decision-making and patient management.

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New research published in the American Journal of Roentgenology (AJR) indicates that MR elastography (MRE) could play a vital role in noninvasively monitoring liver stiffness, a surrogate marker for fibrosis, in children and young adults with autoimmune liver disease (AILD).

“MRE liver stiffness measurements were overall elevated in children and young adults with AILD, although were not significantly different between subsets of patients with primary sclerosing cholangitis (PSC)/autoimmune sclerosing cholangitis (ASC) and autoimmune hepatitis (AIH),” writes first author and AJR Pediatric Imaging Section Editor Jonathan R. Dillman, MD, from Cincinnati Children’s Hospital Center. 

Youth Liver Health Revealed

The study by Dillman and his colleagues leveraged an institutional registry of children and young adults diagnosed with AILD, ASC, or AIH. They pinpointed subjects who underwent both a research abdominal 1.5-T MRI with liver MRE as part of registry enrollment and a clinically indicated liver biopsy within six months. Liver shear stiffness, measured in kPa, was evaluated using a 2D gradient-recalled echo sequence for MRE. Additionally, they recorded laboratory markers such as the aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis-4 score (FIB-4) to gauge liver fibrosis. A pathologist, blinded to clinical and MRI data, determined the histologic METAVIR liver fibrosis stage.

MRI Stiffness Correlates with Liver Fibrosis

In the end, MRE liver stiffness measurements displayed robust correlations with both METAVIR (rho=0.68) and Ishak (rho=0.67) histologic fibrosis scores. Additionally, MRE liver stiffness exhibited an AUC of 0.81 (95% CI: 0.67-0.91) for detecting advanced histologic liver fibrosis (F0-F1 vs F2-F4), achieving a sensitivity of 65.4% and specificity of 90.0% at a cutoff of >3.29 kPa.

Featured image: A, Coronal maximum intensity projection MRCP image shows multiple intrahepatic strictures (dotted arrows), narrowing of common bile duct (solid arrow), and mild dilation of central biliary tree (dashed arrow). B, Axial T2-weighted fast spin echo MR image with fat suppression shows enlarged liver with increased T2-weighted signal intensity. C, Axial MR elastogram image shows heterogeneous appearance of liver with abnormal stiffening (mean liver stiffness, 6.55 kPa). D, Tissue specimen (Mason trichrome stain; digital scan at 1x magnification) from percutaneous liver biopsy shows abnormally increased fibrosis (blue).