Staging Liver Fibrosis: Comparison of Native <scp>T1</scp> Mapping, <scp>T2</scp> Mapping, and T1ρ: An Experimental Study in Rats With Bile Duct Ligation and Carbon Tetrachloride at 11.<scp>7 T MRI</scp>

Abstract

Background T1, T2, and T1ρ 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 T1ρ for noninvasively staging liver fibrosis in bile duct ligation (BDL) or carbon tetrachloride (CCl 4 ) model. Study Type Prospective animal model. Subjects Liver fibrosis was induced by BDL or injection of CCl 4 in 120 rats. Field Strength/Sequence 11.7 T, T1 mapping with 10 repetition times, T2 mapping with 32 echo times, and T1ρ with 10 spin‐lock times. Assessment T1, T2, and T1ρ 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 T1ρ 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 &lt; 0.05 was considered statistically significant). Results T1, T2, and T1ρ (BDL: rho = 0.73, 0.85, 0.68; CCl 4 : 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 CCl 4 model ( P = 0.204). The area under the curves (AUCs) range of T1, T2, and T1ρ for predicting ≥F1, ≥F2, ≥F3, and F4 were 0.76–0.95, 0.89–0.98, and 0.80–0.94 in the CCl 4 model. For the CCl 4 model, the AUCs range of T1, T2, and T1ρ 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 CCl 4 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 T1ρ. T2 may not be suitable for evaluating liver fibrosis. Level of Evidence 1 Technical Efficacy Stage 2