Assessment of Imaging Modalities Against Liver Biopsy in Nonalcoholic Fatty Liver Disease: The Amsterdam NAFLD‐NASH Cohort

BACKGROUND: Noninvasive diagnostic methods are urgently required in disease stratification and monitoring in nonalcoholic fatty liver disease (NAFLD). Multiparametric magnetic resonance imaging (MRI) is a promising technique to assess hepatic steatosis, inflammation, and fibrosis, potentially enabling noninvasive identification of individuals with active and advanced stages of NAFLD. PURPOSE: To examine the diagnostic performance of multiparametric MRI for the assessment of disease severity along the NAFLD disease spectrum with comparison to histological scores. STUDY TYPE: Prospective, cohort. POPULATION: Thirty‐seven patients with NAFLD. FIELD STRENGTH/SEQUENCE: Multiparametric MRI at 3.0 T consisted of magnetic resonance (MR) spectroscopy (MRS) with multi‐echo stimulated‐echo acquisition mode, magnitude‐based and three‐point Dixon using a two‐dimensional multi‐echo gradient echo, MR elastography (MRE) using a generalized multishot gradient‐recalled echo sequence and intravoxel incoherent motion (IVIM) using a multislice diffusion weighted single‐shot echo‐planar sequence. ASSESSMENT: Histological steatosis grades were compared to proton density fat fraction measured by MRS (PDFF(MRS)), magnitude‐based MRI (PDFF(MRI‐M)), and three‐point Dixon (PDFF(Dixon)), as well as FibroScan® controlled attenuation parameter (CAP). Fibrosis and disease activity were compared to IVIM and MRE. FibroScan® liver stiffness measurements were compared to fibrosis levels. Diagnostic performance of all imaging parameters was determined for distinction between simple steatosis and nonalcoholic steatohepatitis (NASH). STATISTICAL TESTS: Spearman's rank test, Kruskal–Wallis test, Dunn's post‐hoc test with Holm‐Bonferroni P‐value adjustment, receiver operating characteristic curve analysis. A P‐value <0.05 was considered statistically significant. RESULTS: Histological steatosis grade correlated significantly with PDFF(MRS) (r ( s ) = 0.66, P < 0.001), PDFF(MRI‐M) (r ( s ) = 0.68, P < 0.001), and PDFF(Dixon) (r ( s ) = 0.67, P < 0.001), whereas no correlation was found with CAP. MRE and IVIM diffusion and perfusion significantly correlated with disease activity (r ( s ) = 0.55, P < 0.001, r ( s ) = −0.40, P = 0.016, r ( s ) = −0.37, P = 0.027, respectively) and fibrosis (r ( s ) = 0.55, P < 0.001, r ( s ) = −0.46, P = 0.0051; r ( s ) = −0.53, P < 0.001, respectively). MRE and IVIM diffusion had the highest area‐under‐the‐curve for distinction between simple steatosis and NASH (0.79 and 0.73, respectively). DATA CONCLUSION: Multiparametric MRI is a promising method for noninvasive, accurate, and sensitive distinction between simple hepatic steatosis and NASH, as well as for the assessment of steatosis and fibrosis severity. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: 2