Dataset Information

Hepatic R2* is more strongly associated with proton density fat fraction than histologic liver iron scores in patients with nonalcoholic fatty liver disease.

ABSTRACT:

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.

SUBMITTER: Bashir MR

PROVIDER: S-EPMC6449180 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Hepatic R2* is more strongly associated with proton density fat fraction than histologic liver iron scores in patients with nonalcoholic fatty liver disease.

Bashir Mustafa R MR Wolfson Tanya T Gamst Anthony C AC Fowler Kathryn J KJ Ohliger Michael M Shah Shetal N SN Alazraki Adina A Trout Andrew T AT Behling Cynthia C Allende Daniela S DS Loomba Rohit R Sanyal Arun A Schwimmer Jeffrey J Lavine Joel E JE Shen Wei W Tonascia James J Van Natta Mark L ML Mamidipalli Adrija A Hooker Jonathan J Kowdley Kris V KV Middleton Michael S MS Sirlin Claude B CB

Journal of magnetic resonance imaging : JMRI 20181014 5

<h4>Background</h4>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.<h4>Purpose</h4>To identify the most influential covariates for liver R2* values in patients with nonalcoholic fatty liver disease (NAFLD).<h4>Study type</h4>Retrospective analysis of prospectively acquired data.<h4>Population</h4>Baseline data from 204 subjects enrolled in NAFLD/NASH (nonalcoholic steatohepatitis) treatment trials.<h4>F ...[more]

PMID: 30318834

Similar Datasets

Project description:Background & aimsPatients with nonalcoholic fatty liver disease (NAFLD) or nonalcoholic steatohepatitis (NASH) often require histologic assessment via liver biopsy. Magnetic resonance imaging (MRI)-based methods for measuring liver triglycerides based on proton density fat fraction (PDFF) are increasingly used as a noninvasive tool to identify patients with hepatic steatosis and to assess for change in liver fat over time. We aimed to determine whether MRI-PDFF accurately reflects a variety of liver histology features in patients with NAFLD or NASH.MethodsWe performed a retrospective analysis of pooled data from 3 phase 2a trials of pharmacotherapies for NAFLD or NASH. We collected baseline clinical, laboratory, and histopathology data on all subjects who had undergone MRI analysis in 1 of the trials. We assessed the relationship between liver PDFF values and liver histologic findings using correlation and area under the receiver operating characteristic (AUROC) analyses. As an ancillary analysis, we also simulated a clinical trial selection process and calculated subject exclusion rates and differences in population characteristics caused by PDFF inclusion thresholds of 6% to 15%.ResultsIn 370 subjects, the mean baseline PDFF was 17.4% ± 8.6%. Baseline PDFF values correlated with several histopathology parameters, including steatosis grade (r = 0.78; P < .001), NAFLD activity score (NAS, r = 0.54; P < .001), and fibrosis stage (r = -0.59; P < .001). However, PDFF did not accurately identify patients with NAS ≥ 4 (AUROC = 0.72) or fibrosis stage ≥3 (AUROC = 0.66). In a theoretical trial of these subjects, exclusion rates increased as PDFF minimum threshold level increased. There were no significant differences in cohort demographics when PDFF thresholds ranging from 6% to 15% were used, and differences in laboratory and histopathology data were small.ConclusionsIn an analysis of patients with NAFLD or NASH, we determined that although The MRI-PDFF correlated with steatosis grade and NAS, and inversely with fibrosis stage, it was suboptimal in identification of patients with NAS >4 or advanced fibrosis. Although MRI-PDFF is an important imaging biomarker for continued evaluation of this patient population, liver biopsy analysis is still necessary.

Project description:ObjectiveTo investigate the diagnostic performance of quantitative ultrasound (US) parameters for the assessment of hepatic steatosis in patients with nonalcoholic fatty liver disease (NAFLD) using magnetic resonance imaging proton density fat fraction (MRI-PDFF) as the reference standard.Materials and methodsIn this single-center prospective study, 120 patients with clinically suspected NAFLD were enrolled between March 2019 and January 2020. The participants underwent US examination for radiofrequency (RF) data acquisition and chemical shift-encoded liver MRI for PDFF measurement. Using the RF data analysis, the attenuation coefficient (AC) based on tissue attenuation imaging (TAI) (AC-TAI) and scatter-distribution coefficient (SC) based on tissue scatter-distribution imaging (TSI) (SC-TSI) were measured. The correlations between the quantitative US parameters (AC and SC) and MRI-PDFF were evaluated using Pearson correlation coefficients. The diagnostic performance of AC-TAI and SC-TSI for detecting hepatic fat contents of ≥ 5% (MRI-PDFF ≥ 5%) and ≥ 10% (MRI-PDFF ≥ 10%) were assessed using receiver operating characteristic (ROC) analysis. The significant clinical or imaging factors associated with AC and SC were analyzed using linear regression analysis.ResultsThe participants were classified based on MRI-PDFF: < 5% (n = 38), 5-10% (n = 23), and ≥ 10% (n = 59). AC-TAI and SC-TSI were significantly correlated with MRI-PDFF (r = 0.659 and 0.727, p < 0.001 for both). For detecting hepatic fat contents of ≥ 5% and ≥ 10%, the areas under the ROC curves of AC-TAI were 0.861 (95% confidence interval [CI]: 0.786-0.918) and 0.835 (95% CI: 0.757-0.897), and those of SC-TSI were 0.964 (95% CI: 0.913-0.989) and 0.935 (95% CI: 0.875-0.972), respectively. Multivariable linear regression analysis showed that MRI-PDFF was an independent determinant of AC-TAI and SC-TSI.ConclusionAC-TAI and SC-TSI derived from quantitative US RF data analysis yielded a good correlation with MRI-PDFF and provided good performance for detecting hepatic steatosis and assessing its severity in NAFLD.

Dataset Information

Hepatic R2* is more strongly associated with proton density fat fraction than histologic liver iron scores in patients with nonalcoholic fatty liver disease.

Background

Purpose

Study type

Population

Field strength

Assessment

Statistical tests

Results

Data conclusion

Level of evidence

Publications

Hepatic R2* is more strongly associated with proton density fat fraction than histologic liver iron scores in patients with nonalcoholic fatty liver disease.

Similar Datasets

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