A Comparative Study of Three Systems for Liver Magnetic Resonance Elastography

Different MR elastography (MRE) systems may produce different stiffness measurements, making direct comparison difficult in multi-center investigations. To assess the repeatability and reproducibility of liver stiffness measured by three typical MRE systems. Prospective. Thirty volunteers without liver disease history (20 males, aged 21-28)/5 gel phantoms. 3.0 T United Imaging Healthcare (UIH), 1.5 T Siemens Healthcare, 3.0 T General Electric Healthcare (GE)/Echo planar imaging-based MRE sequence. Wave images of volunteers and phantoms were acquired by three MRE systems. Tissue stiffness was evaluated by two observers, while phantom stiffness was assessed automatically by code. The reproducibility across three MRE systems was quantified based on the mean stiffness of each volunteer and phantom. Intraclass correlation coefficients (ICC), coefficients of variation (CV), and Bland-Altman analyses were used to assess the interobserver reproducibility, the interscan repeatability, and the intersystem reproducibility. Paired t-tests were performed to assess the interobserver and interscan variation. Friedman tests with Dunn's multiple comparison correction were performed to assess the intersystem variation. P values less than 0.05 indicated significant difference. The reproducibility of stiffness measured by the two observers demonstrated consistency with ICC > 0.92, CV 0.96, CV