Assessing liver fibrosis in chronic liver disease: Comparison of diffusion-weighted MR elastography and two-dimensional shear-wave elastography using histopathologic assessment as the reference standard.

Abstract

Introduction and objectives: Liver stiffness measurement (LSM) by two-dimensional shear-wave elastography (2D SWE) is a well-established method for assessing hepatic fibrosis. Diffusion-weighted imaging (DWI) can be converted into virtual shear modulus (µ_Diff) to estimate liver elasticity. The purpose of this study was to correlate and compare the diagnostic performance of DWI-based virtual elastography and 2D SWE for staging hepatic fibrosis in patients with chronic liver disease, using histopathologic assessment as the reference standard.

Patients and methods: This retrospective study included 111 patients who underwent preoperative multiple b-value DWI and 2D SWE. The µ_Diff was calculated using DWI acquisition with b-values of 200 and 1,500 /mm², and LSM was obtained by 2D SWE. Correlation between µ_Diff and LSM was assessed, as well as the correlation between these noninvasive methods and histologic fibrosis stages. The diagnostic efficacy of µ_Diff and LSM for staging liver fibrosis was compared with receiver operating characteristic (ROC) curve analysis.

Results: There was a significant positive correlation between µ_Diff and LSM (rho= 0.48, P < 0.001). µ_Diff (rho= 0.54, P < 0.001) and LSM (rho= 0.76, P < 0.001) were positively correlated with liver fibrosis stages. Areas under the curves (AUCs) of µ_Diff and LSM, respectively, were 0.81 and 0.90 for significant fibrosis, 0.89 and 0.98 for advanced fibrosis, and 0.77 and 0.91 for cirrhosis. The AUCs of 2D SWE for diagnosing advanced fibrosis and cirrhosis were significantly higher than those of µ_Diff (P < 0.05 for both).

Conclusions: LSM by 2D SWE yields larger AUCs compared to µ_Diff obtained from DWI-based virtual elastography for various stages of liver fibrosis. LSM is superior to µ_Diff in predicting advanced fibrosis and cirrhosis.