title: Noninvasive quantification of hepatic fat content using three-echo dixon magnetic resonance imaging with correction for T2* relaxation effects.
abstract: OBJECTIVE
  To investigate three-echo T2*-corrected Dixon magnetic resonance imaging (MRI) for noninvasively estimating hepatic fat content (HFC) compared with biopsy.
  
  
  METHODS
  One hundred patients (50 men, 50 women; mean age, 57.7±14.2 years) underwent clinically indicated liver core biopsy (102 valid tissue samples) and liver MRI 24 to 72 hours later. MRI was performed at 1.5T (Magnetom Avanto, Siemens Healthcare, Erlangen, Germany) using Dixon imaging with T2* correction (work in progress, WIP-432.rev.1, Siemens Healthcare). An ultrafast breath-hold three-echo 3D-gradient echo sequence with TR/TE1/TE2/TE3 of 11/2.4/4.8/9.6 milliseconds, and online calculation of T2*-corrected water images (signal intensities of water [SIW]), fat images (SIF), and fat content map (SIFAT=10×SIF/(SIW+SIF)) was used. SIs of the calculated fat content map (SIFAT) were verified using the histologically quantified HFC (HFC(path)). Spearman correlation for HFC(path) and SIFAT was calculated. Stage of fibrosis, hepatic iron content, and patterns of liver fat (macrovesicular, microvesicular, mixed) and their influence on predicting HFC by MRI were determined.
  
  
  RESULTS
  Correlation between SIFAT and HFC(path) was rspearman=0.89. Agreement between HFC predicted by MRI and HFC(path) calculated by nonlinear saturation-growth regression was rspearman=0.89. Kruskal-Wallis analysis revealed no significant difference for SIFAT across fibrosis grades (P=0.90) and liver iron content (P=0.76). Regarding the cellular architecture of liver fat, the microvesicular pattern showed lower mean ranks in SI than macrovesicular and mixed patterns (P=0.01).
  
  
  CONCLUSIONS
  T2*-corrected Dixon MRI is a noninvasive tool for estimating HFC, showing excellent correlation with liver biopsy without being limited by liver iron content and fibrosis/cirrhosis.
authors.affiliation: Department of Radiology, Ernst Moritz Arndt University Greifswald, Greifswald, Germany. kuehn@uni-greifswald.de
authors.forename: Jens-Peter
authors.initials: JP
authors.lastname: Kühn
authors.forename: Matthias
authors.initials: M
authors.lastname: Evert
authors.forename: Nele
authors.initials: N
authors.lastname: Friedrich
authors.forename: Stephan
authors.initials: S
authors.lastname: Kannengiesser
authors.forename: Julia
authors.initials: J
authors.lastname: Mayerle
authors.forename: Robert
authors.initials: R
authors.lastname: Thiel
authors.forename: Markus M
authors.initials: MM
authors.lastname: Lerch
authors.forename: Frank
authors.initials: F
authors.lastname: Dombrowski
authors.forename: Birger
authors.initials: B
authors.lastname: Mensel
authors.forename: Norbert
authors.initials: N
authors.lastname: Hosten
authors.forename: Ralf
authors.initials: R
authors.lastname: Puls
mesh_terms: D005234:Fatty Liver / Q000473:pathology*; D005260:Female; D005355:Fibrosis / Q000473:pathology; D006801:Humans; D007501:Iron / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results
chemical_list: D007501:Iron