All activities related to animal subjects were reviewed and approved by the Mayo Clinic institutional animal care and use committee. A total of 182 mice and 5 pigs were used in this study. These animals represent models of five different liver diseases (knockout autosomal recessive polycystic kidney disease, carbon tetrachloride induced liver disease, nonalcoholic fatty liver disease, hepatic venous congestion, fumarylacetoacetate hydrolase deficient disease) with a prior power analysis performed to justify the number of mice in each subgroup (see Appendix), with the pigs being used to complete and demonstrate the big picture of varying MRE parameters in the long history of chronic liver disease because all the mouse models had moderate to severe liver fibrosis without substantial complications. 27 mice of congestion model and 5 pigs have been assessed in other studies (14 (link), 15 ), which are focused on the mechanism of disease, not imaging techniques. Different protocols involving one-time or repeated MRE imaging, tissue harvesting, blood collection, and portal pressure measurement were performed before the specified animal euthanasia time in each subgroup are given in Table 1, while the details of the imaging and testing protocols are given in the Appendix. The experimental setups for mouse and pig models are shown in Figure 1(a) and (b) respectively.