Assessment of Nonalcoholic Fatty Liver Disease in Rats Using Quantitative Dynamic Contrast-Enhanced MRI

Purpose: To evaluate the usefulness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in the assessment of nonalcoholic fatty liver disease (NAFLD) severity. Materials and Methods: Liver DCE-MRI at 3.0T was performed in 36 adult Sprague Dawley rats with methionine choline-deficient diet-induced NAFLD and 10 untreated control rats. Pharmacokinetic parameters of DCE-MRI including '<trans, Kep, V Vp, and hepatic portal index (HPoI) were measured using the dual-input extended Tofts model. Animals were categorized as normal (n 10), simple steatosis (SS, n = 11), borderline nonalcoholic steatohepatitis (bNASH, n 20), and NASH (n 5) subgroups according to the NAFLD activity score system, and classified into FO (n 24), F1 (n = 11), F2 (n = 7), and F3 (n = 4) subgroups according to an established scoring system. DCE-MRI parameters were compared. Receiver operating characteristic analyses were performed to assess the diagnostic performance of various DCE-MRI parameters in grading NAFLD activity and staging liver fibrosis. Results: K-trans and HPoI were elevated with increasing severity of NAFLD activity and increased fibrosis stage. The areas under the receiver operating characteristic curve (AUROCs) of HPoI ranged from 0.895-0.951 for discriminating between different grades of NAFLD activity, and the AUROC was 0.852 for discriminating FO stage from overall F1 F3 stages. The AUROC of K-trans for discriminating non-NASH from bNASH and NASH groups was 0.968, and 0.898 for discriminating between normal and overall fibrosis groups. Conclusion: DCE-MRI may play a role in assessing NAFLD severity.