title: Improved T1, contrast concentration, and pharmacokinetic parameter quantification in the presence of fat with two-point Dixon for dynamic contrast-enhanced magnetic resonance imaging.
abstract: OBJECTIVE
  To evaluate the impact of fat and fat-suppression on the quantification of T1, gadolinium concentration, and pharmacokinetic parameters in DCE-MRI.
  
  
  METHODS
  T1 values were measured in fat-free phantoms using variable flip angle with no fat suppression, quick or interleaved fat saturation (QFS), or two-point Dixon and were compared with reference values measured with inversion recovery-prepared turbo spin echo. Relaxivity of gadolinium-benzyloxypropionictetraacetate (Gd-BOPTA) was measured in emulsions of Gd-BOPTA solution and fat using Dixon in-phase and water-only images. Liver T1 and pharmacokinetic parameters of 15 patients were calculated from Dixon in-phase and water-only images and were correlated with liver fat signal fraction.
  
  
  RESULTS
  T1 values measured using Dixon water-only and non-fat-suppressed images matched the reference values; while T1 values measured using QFS showed large deviations. Relaxivities and Gd measured in the Dixon water-only images were less affected by the fat than those measured in the in-phase images. The correlation between liver fat fraction and the differences in measured pharmacokinetic parameters using Dixon in-phase and water-only images were significant (P < 0.05) for T1, K(trans), and incremental area under the curve, but not Ve (P = 0.1).
  
  
  CONCLUSIONS
  Dixon water-only images provided more reliable estimation of T1, Gd, and pharmacokinetic parameters when fat was present.
authors.affiliation: Department of Radiology and Imaging Science, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Le
authors.affiliation: Siemens Medical Solutions, USA, MR R&D, Morrisville, North Carolina, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Dale
authors.affiliation: Department of Radiology and Imaging Science, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Fatih
authors.initials: F
authors.lastname: Akisik
authors.affiliation: Department of Radiology, Indiana University Health, Indianapolis, Indiana, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Koons
authors.affiliation: Department of Radiology and Imaging Science, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Chen
authors.initials: C
authors.lastname: Lin
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging* / Q000502:physiology; D000293:Adolescent; D000328:Adult; D000368:Aged; D003287:Contrast Media / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D016014:Linear Models; D008099:Liver / Q000000981:diagnostic imaging / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
chemical_list: D003287:Contrast Media
keywords: DCE-MRI; Dixon; fat suppression; variable flip angle