Omid Yeganeh MD, Abstract Co-Author: Nothing to Disclose

Yakir S. Levin MD, PhD, Abstract Co-Author: Nothing to Disclose

Kevin Amir Zand MD, Abstract Co-Author: Nothing to Disclose

Elhamy Rafat Heba MBBCh, MD, Abstract Co-Author: Nothing to Disclose

Gavin Hamilton PhD, Abstract Co-Author: Nothing to Disclose

Rohit Loomba MD, MSc, Abstract Co-Author: Nothing to Disclose

Jeffrey B. Schwimmer MD, Abstract Co-Author: Nothing to Disclose

Claude B. Sirlin MD, Abstract Co-Author: Research Grant, General Electric Company Speakers Bureau, Bayer AG Consultant, Bayer AG

Michael Simca Middleton MD, PhD, Presenter: Consultant, Allergan, Inc Institutional research contract, Bayer AG Institutional research contract, sanofi-aventis Group Institutional research contract, Isis Pharmaceuticals, Inc Institutional research contract, Johnson & Johnson Institutional research contract, Synageva BioPharma Corporation Institutional research contract, Takeda Pharmaceutical Company Limited Stockholder, General Electric Company Stockholder, Pfizer Inc Institutional research contract, Pfizer Inc

To measure intra- and inter-examination precision, and accuracy using magnetic resonance spectroscopy (MRS) as reference, of magnitude- and complex-based multi-echo gradient-echo MRI (mMRI and cMRI, respectively) for estimation of hepatic proton density fat fraction (PDFF) in obese adults and children.

In this prospective, IRB-approved, HIPAA-compliant study, obese adults and children were enrolled after obtaining written informed consent. Three 3T MRI examinations were performed, with subjects being taken off and placed back on the scanner table between examinations. Each MRI examination consisted of three MRI acquisitions, each including mMRI, cMRI, and a magnetic resonance spectroscopy (MRS) acquisition from a voxel location in the right lobe. Hence, each subject had nine data points for each method (mMRI and cMRI). Two intra- and inter-examination precision metrics were computed: standard deviation (SD), and range. Accuracy of mMRI PDFF and cMRI PDFF, using MRS as a reference, was measured using Bland-Altman plots and linear regression.

Twenty-nine subjects were enrolled (23 male, 6 female; mean age 23.7 ± 14.02 years; age range 12 to 59 years; body mass index (BMI) 37 ± 5.6 kg/m2, BMI range 28.1 to 51.1 kg/m2). PDFF standard deviations for intra- and inter-examination precision were 0.12% and 0.36% for mMRI, and 0.29% and 0.38% for cMRI, respectively. Ranges of PDFF standard deviation were 0.53% to 1.71% for mMRI, and 1.17% to 1.56% for cMRI, respectively. Regression intercepts were 1.70% and 0.82%, and regression slopes were 0.99 and 0.94, for mMRI and cMRI respectively, using MRS as a reference standard.

Both mMRI and cMRI demonstrated excellent intra- and inter-examination repeatability. mMRI and cMRI showed similar accuracy in hepatic PDFF estimation using MRS as a reference standard.

Both mMRI and cMRI are likely to sufficiently precise to be useful in hepatic PDFF longitudinal monitoring studies.

Yeganeh, O, Levin, Y, Zand, K, Heba, E, Hamilton, G, Loomba, R, Schwimmer, J, Sirlin, C, Middleton, M, Intra- and Inter-examination Precision, and Accuracy of Magnitude-based and Complex-based MRI for Estimation of Hepatic Proton Density Fat Fraction (PDFF) in a Population of Obese Adults and Children.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14015943.html