Staging Liver Fibrosis: Comparison of Native T1 Mapping, T2 Mapping, and T1 rho: An Experimental Study in Rats With Bile Duct Ligation and Carbon Tetrachloride at 11.7 T MRI

Background: T1, T2, and T1 rho might be potential biomarkers for assessing liver fibrosis. However, few studies reported the value of them in different animal models. Purpose: To investigate and compare the performances of T1, T2, and T1 rho for noninvasively staging liver fibrosis in bile duct ligation (BDL) or carbon tetrachloride (CCl4) model. Study Type: Prospective animal model. Subjects: Liver fibrosis was induced by BDL or injection of CCl4 in 120 rats. Field Strength/Sequence: 11.7 T, T1 mapping with 10 repetition times, T2 mapping with 32 echo times, and T1 rho with 10 spin-lock times. Assessment: T1, T2, and T1 rho were measured and correlated with liver fibrosis stages, as well as the degree of inflammation, steatosis, iron deposition, and the expression of cytokeratin 19. The discriminative performance of T1, T2, and T1 rho for staging liver fibrosis was compared. Statistical Tests: One-way analysis of variance (ANOVA), Spearman's correlation analysis, factorial design ANOVA, and receiver operating characteristic curves (P < 0.05 was considered statistically significant). Results: T1, T2, and T1 rho (BDL: rho = 0.73, 0.85, 0.68; CCl4 : rho = 0.80, 0.29, 0.61) were significantly correlated with liver fibrosis stages, while there was no significant difference in T2 among stage F0-F4 in the CCl4 model (P = 0.204). The area under the curves (AUCs) range of T1, T2, and T1 rho for predicting >= F1, >= F2, >= F3, and F4 were 0.76-0.95, 0.89-0.98, and 0.80-0.94 in the CCl4 model. For the CCl4 model, the AUCs range of T1, T2, and T1 rho for predicting >= F1, >= F2, >= F3, and F4 were 0.83-0.95, 0.61-0.74, and 0.73-0.89, respectively. T2 had significantly higher AUC in the BDL model than CCl4 model for diagnosing liver fibrosis. Data Conclusion: The most sensitive and accurate method for staging liver fibrosis appeared to be T1 in our animal models followed by T1 rho. T2 may not be suitable for evaluating liver fibrosis.