Diffusion-weighted MRI-based Virtual Elastography for the Assessment of Liver Fibrosis

Area of Science:

• Radiology
• Medical Imaging
• Hepatology

Background:

• Noninvasive liver fibrosis staging is crucial for patient management.
• Diffusion-weighted (DW) MRI-based elastography is a novel technique for liver fibrosis assessment.
• Further validation in larger patient cohorts is needed for DW MRI-based elastography.

Purpose of the Study:

• To compare the efficacy of DW MRI and MR elastography (MRE) in assessing liver fibrosis.
• To evaluate the diagnostic performance of DW MRI-derived virtual shear modulus (μDiff) against MRE-derived shear modulus (μMRE).

Main Methods:

• Retrospective analysis of 74 patients undergoing both MRE and DW MRI.
• Calculation of μMRE from MRE stiffness maps and μDiff from DW MRI shifted apparent diffusion coefficient (ADC).
• Comparison of fibrosis staging between DW MRI and MRE, alongside assessment of serum fibrosis markers.

Main Results:

• Strong correlation (r² = 0.81) and high agreement between μMRE and μDiff values.
• DW MRI-based staging agreed with MRE-based staging in 55% of patients; agreement within one stage in 35%.
• Binarized staging (insignificant vs. significant fibrosis) showed 85% agreement (κ = 0.85).
• μDiff demonstrated superior performance (AUC, 0.79) in discriminating advanced fibrosis (F3-F4) compared to serum markers (AUC, 0.50-0.69).

Conclusions:

• DW MRI-based liver fibrosis staging shows high agreement with MRE.
• DW MRI offers a potential noninvasive alternative to MRE, eliminating the need for mechanical vibration setup.
• Combining DW MRI with serum markers may enhance fibrosis discrimination.