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Hepatic R2* is more strongly associated with proton density fat fraction than histologic liver iron scores in patients with nonalcoholic fatty liver disease
Author(s) -
Bashir Mustafa R.,
Wolfson Tanya,
Gamst Anthony C.,
Fowler Kathryn J.,
Ohliger Michael,
Shah Shetal N.,
Alazraki Adina,
Trout Andrew T.,
Behling Cynthia,
Allende Daniela S.,
Loomba Rohit,
Sanyal Arun,
Schwimmer Jeffrey,
Lavine Joel E.,
Shen Wei,
Tonascia James,
Van Natta Mark L.,
Mamidipalli Adrija,
Hooker Jonathan,
Kowdley Kris V.,
Middleton Michael S.,
Sirlin Claude B.
Publication year - 2019
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.26312
Subject(s) - nonalcoholic fatty liver disease , steatosis , medicine , fatty liver , covariate , gastroenterology , nonalcoholic steatohepatitis , steatohepatitis , fibrosis , population , disease , mathematics , statistics , environmental health
Background The liver R2* value is widely used as a measure of liver iron but may be confounded by the presence of hepatic steatosis and other covariates. Purpose To identify the most influential covariates for liver R2* values in patients with nonalcoholic fatty liver disease (NAFLD). Study Type Retrospective analysis of prospectively acquired data. Population Baseline data from 204 subjects enrolled in NAFLD/NASH (nonalcoholic steatohepatitis) treatment trials. Field Strength 1.5T and 3T; chemical‐shift encoded multiecho gradient echo. Assessment Correlation between liver proton density fat fraction and R2*; assessment for demographic, metabolic, laboratory, MRI‐derived, and histological covariates of liver R2*. Statistical Tests Pearson's and Spearman's correlations; univariate analysis; gradient boosting machines (GBM) multivariable machine‐learning method. Results Hepatic proton density fat fraction (PDFF) was the most strongly correlated covariate for R2* at both 1.5T ( r = 0.652, P < 0.0001) and at 3T ( r = 0.586, P < 0.0001). In the GBM analysis, hepatic PDFF was the most influential covariate for hepatic R2*, with relative influences (RIs) of 61.3% at 1.5T and 47.5% at 3T; less influential covariates had RIs of up to 11.5% at 1.5T and 16.7% at 3T. Nonhepatocellular iron was weakly associated with R2* at 3T only (RI 6.7%), and hepatocellular iron was not associated with R2* at either field strength. Data Conclusion Hepatic PDFF is the most influential covariate for R2* at both 1.5T and 3T; nonhepatocellular iron deposition is weakly associated with liver R2* at 3T only. Level of Evidence: 4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:1456–1466.