title: In vivo breath-hold (1) H MRS simultaneous estimation of liver proton density fat fraction, and T1 and T2 of water and fat, with a multi-TR, multi-TE sequence.
abstract: OBJECTIVE
  To examine the intra-examination repeatability of proton density fat fraction (PDFF) and T1 and T2 of liver water and fat as estimated by a novel multi-repetition time (TR)-echo time (TE) (1) H magnetic resonance spectroscopy (MRS)-stimulated echo acquisition mode (STEAM) sequence that acquires 32 spectra for a range of TRs and TEs in single breath-hold.
  
  
  METHODS
  Sixty-seven subjects undergoing liver MRI examinations at 3T had three multi-TR-TE sequences acquired consecutively in a single session. This sequence was designed to allow accurate estimation of T1 and T2 of both water and fat, as well as PDFF, in a single breath-hold. A standard long-TR, multi-TE sequence was also acquired to allow comparison of estimated PDFF. Regression and interclass correlation (ICC) analyses were performed.
  
  
  RESULTS
  There was strong agreement between PDFF estimated by the multi-TR-TE and long-TR, multi-TE sequences (slope 0.997; intercept -0.03; R = 0.997). The multi-TR-TE sequence had high repeatability for estimating PDFF (ICC = 0.999), water T2 (ICC = 0.920), water T1 (ICC = 0.845), and fat T2 (ICC = 0.760), and moderate repeatability for estimating fat T1 (ICC = 0.556).
  
  
  CONCLUSIONS
  A novel multi-TR-TE sequence can estimate PDFF and water and fat T1 and T2 in a single breath-hold. Refinement may be needed to improve repeatability for fat T1 estimation.
authors.affiliation: Liver Imaging Group, Department of Radiology, University of California, San Diego, San Diego, California, USA.
authors.forename: Gavin
authors.initials: G
authors.lastname: Hamilton
authors.affiliation: Liver Imaging Group, Department of Radiology, University of California, San Diego, San Diego, California, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Middleton
authors.affiliation: Liver Imaging Group, Department of Radiology, University of California, San Diego, San Diego, California, USA.
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Hooker
authors.affiliation: Liver Imaging Group, Department of Radiology, University of California, San Diego, San Diego, California, USA.
authors.forename: William M
authors.initials: WM
authors.lastname: Haufe
authors.affiliation: Department of Family Medicine and Public Health, University of California, San Diego, San Diego, California, USA.
authors.forename: Nketi I
authors.initials: NI
authors.lastname: Forbang
authors.affiliation: Department of Family Medicine and Public Health, University of California, San Diego, San Diego, California, USA.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Allison
authors.affiliation: Department of Family Medicine and Public Health, University of California, San Diego, San Diego, California, USA.|NAFLD Translational Research Unit, Division of Gastroenterology, Department of Medicine, University of California, San Diego, San Diego, California, USA.
authors.forename: Rohit
authors.initials: R
authors.lastname: Loomba
authors.affiliation: Liver Imaging Group, Department of Radiology, University of California, San Diego, San Diego, California, USA.
authors.forename: Claude B
authors.initials: CB
authors.lastname: Sirlin
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism* / Q000473:pathology; D050154:Adiposity; D000465:Algorithms; D001834:Body Water / Q000378:metabolism*; D062485:Breath Holding; D005260:Female; D006801:Humans; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000378:metabolism* / Q000473:pathology; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: NAFLD; NASH; magnetic resonance spectroscopy; relaxation