title: Liver fat quantification: Comparison of dual-echo and triple-echo chemical shift MRI to MR spectroscopy.
abstract: OBJECTIVE
  To assess the diagnostic value of MRI using dual-echo (2PD) and triple-echo (3PD) chemical shift imaging for liver fat quantification against multi-echo T2 corrected MR spectroscopy (MRS) used as the reference standard, and examine the effect of T2(*) imaging on accuracy of MRI for fat quantification.
  
  
  METHODS
  Patients who underwent 1.5T liver MRI that incorporated 2PD, 3PD, multi-echo T2(*) and MRS were included in this IRB approved prospective study. Regions of interest were placed in the liver to measure fat fraction (FF) with 2PD and 3PD and compared with MRS-FF. A random subset of 25 patients with a wide range of MRS-FF was analyzed with an advanced FF calculation method, to prove concordance with the 3PD. The statistical analysis included correlation stratified according to T2(*), Bland-Altman analysis, and calculation of diagnostic accuracy for detection of MRS-FF>6.25%.
  
  
  RESULTS
  220 MRI studies were identified in 217 patients (mean BMI 28.0±5.6). 57/217 (26.2%) patients demonstrated liver steatosis (MRS-FF>6.25%). Bland-Altman analysis revealed strong agreement between 3PD and MRS (mean±1.96 SD: -0.5%±4.6%) and weaker agreement between 2PD and MRS (4.7%±16.0%). Sensitivity of 3PD for diagnosing FF> 6.25% was higher than that of 2PD. 3PD-FF showed minor discrepancies (coefficient of variation <10%) from FF measured with the advanced method.
  
  
  CONCLUSIONS
  Our large series study validates the use of 3PD chemical shift sequence for detection of liver fat in the clinical environment, even in the presence of T2(*) shortening.
authors.affiliation: Department of Radiology, Body MRI, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, United States; Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, United States.
authors.forename: Janakan
authors.initials: J
authors.lastname: Satkunasingham
authors.affiliation: Department of Radiology, Body MRI, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, United States; Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, United States.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Besa
authors.affiliation: Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, United States.
authors.forename: Octavia
authors.initials: O
authors.lastname: Bane
authors.affiliation: Department of Radiology, Body MRI, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, United States.
authors.forename: Ami
authors.initials: A
authors.lastname: Shah
authors.affiliation: Siemens AG, Healthcare Sector, Erlangen, Germany.
authors.forename: André
authors.initials: A
authors.lastname: de Oliveira
authors.affiliation: Siemens AG, Healthcare Sector, Erlangen, Germany.
authors.forename: Wesley D
authors.initials: WD
authors.lastname: Gilson
authors.affiliation: Siemens AG, Healthcare Sector, Erlangen, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Kannengiesser
authors.affiliation: Department of Radiology, Body MRI, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, United States; Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029, United States. Electronic address: bachir.taouli@mountsinai.org.
authors.forename: Bachir
authors.initials: B
authors.lastname: Taouli
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000328:Adult; D000368:Aged; D005234:Fatty Liver / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008099:Liver / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results
keywords: Dixon method; Fat; Liver; MR spectroscopy