Accuracy of multiecho magnitude-based MRI (M-MRI) for estimation of hepatic proton density fat fraction (PDFF) in children

作者：Zand Kevin A; Shah Amol; Heba Elhamy; Wolfson Tanya; Hamilton Gavin; Lam Jessica; Chen Joshua; Hooker Jonathan C; Gamst Anthony C; Middleton Michael S; Schwimmer Jeffrey B; Sirlin Claude B^*

来源：Journal of Magnetic Resonance Imaging, 2015, 42(5): 1223-1232.

DOI：10.1002/jmri.24888

• MRI
• MRS
• PDFF
• proton density fat fraction
• NAFLD
• liver steatosis

PurposeTo assess accuracy of magnitude-based magnetic resonance imaging (M-MRI) in children to estimate hepatic proton density fat fraction (PDFF) using two to six echoes, with magnetic resonance spectroscopy (MRS) -measured PDFF as a reference standard.
MethodsThis was an IRB-approved, HIPAA-compliant, single-center, cross-sectional, retrospective analysis of data collected prospectively between 2008 and 2013 in children with known or suspected nonalcoholic fatty liver disease (NAFLD). Two hundred eighty-six children (8-20 [mean 14.22.5] years; 182 boys) underwent same-day MRS and M-MRI. Unenhanced two-dimensional axial spoiled gradient-recalled-echo images at six echo times were obtained at 3T after a single low-flip-angle (10 degrees) excitation with120-ms recovery time. Hepatic PDFF was estimated using the first two, three, four, five, and all six echoes. For each number of echoes, accuracy of M-MRI to estimate PDFF was assessed by linear regression with MRS-PDFF as reference standard. Accuracy metrics were regression intercept, slope, average bias, and R-2.
ResultsMRS-PDFF ranged from 0.2-40.4% (mean 13.1 +/- 9.8%). Using three to six echoes, regression intercept, slope, and average bias were 0.46-0.96%, 0.99-1.01, and 0.57-0.89%, respectively. Using two echoes, these values were 2.98%, 0.97, and 2.72%, respectively. R-2 ranged 0.98-0.99 for all methods.
ConclusionUsing three to six echoes, M-MRI has high accuracy for hepatic PDFF estimation in children. J. Magn. Reson. Imaging 2015;42:1223-1232.

• 出版日期2015-11