title: Comparison between modified Dixon MRI techniques, MR spectroscopic relaxometry, and different histologic quantification methods in the assessment of hepatic steatosis.
abstract: OBJECTIVE
  To compare systematically quantitative MRI, MR spectroscopy (MRS), and different histological methods for liver fat quantification in order to identify possible incongruities.
  
  
  METHODS
  Fifty-nine consecutive patients with liver disorders were examined on a 3 T MRI system. Quantitative MRI was performed using a dual- and a six-echo variant of the modified Dixon (mDixon) sequence, calculating proton density fat fraction (PDFF) maps, in addition to single-voxel MRS. Histological fat quantification included estimation of the percentage of hepatocytes containing fat vesicles as well as semi-automatic quantification (qHisto) using tissue quantification software.
  
  
  RESULTS
  In 33 of 59 patients, the hepatic fat fraction was >5% as determined by MRS (maximum 45%, mean 17%). Dual-echo mDixon yielded systematically lower PDFF values than six-echo mDixon (mean difference 1.0%; P < 0.001). Six-echo mDixon correlated excellently with MRS, qHisto, and the estimated percentage of hepatocytes containing fat vesicles (R = 0.984, 0.967, 0.941, respectively, all P < 0.001). Mean values obtained by the estimated percentage of hepatocytes containing fat were higher by a factor of 2.5 in comparison to qHisto. Six-echo mDixon and MRS showed the best agreement with values obtained by qHisto.
  
  
  CONCLUSIONS
  Six-echo mDixon, MRS, and qHisto provide the most robust and congruent results and are therefore most appropriate for reliable quantification of liver fat.
  
  
  CONCLUSIONS
  • Six-echo mDixon correlates excellently with MRS, qHisto, and the estimated percentage of fat-containing hepatocytes. • Six-echo mDixon, MRS, and qHisto provide the most robust and congruent results. • Dual-echo mDixon yields systematically lower PDFF values than six-echo mDixon. • The percentage of fat-containing hepatocytes is 2.5-fold higher than fat fraction determined by qHisto. • Performance characteristics and systematic differences of the various methods should be considered.
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Straße 25, 53127, Bonn, Germany, Guido.Kukuk@ukb.uni-bonn.de.
authors.forename: Guido M
authors.initials: GM
authors.lastname: Kukuk
authors.forename: Kanishka
authors.initials: K
authors.lastname: Hittatiya
authors.forename: Alois M
authors.initials: AM
authors.lastname: Sprinkart
authors.forename: Holger
authors.initials: H
authors.lastname: Eggers
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gieseke
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Block
authors.forename: Philipp
authors.initials: P
authors.lastname: Moeller
authors.forename: Winfried A
authors.initials: WA
authors.lastname: Willinek
authors.forename: Ulrich
authors.initials: U
authors.lastname: Spengler
authors.forename: Jonel
authors.initials: J
authors.lastname: Trebicka
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Fischer
authors.forename: Hans H
authors.initials: HH
authors.lastname: Schild
authors.forename: Frank
authors.initials: F
authors.lastname: Träber
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005234:Fatty Liver / Q000473:pathology*; D005260:Female; D022781:Hepatocytes / Q000473:pathology; D006652:Histological Techniques; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012984:Software; D055815:Young Adult