title: Comparison of R2* correction methods for accurate fat quantification in fatty liver.
abstract: OBJECTIVE
  To compare the performance of fat fraction quantification using single-R(2)* and dual-R(2)* correction methods in patients with fatty liver, using MR spectroscopy (MRS) as the reference standard.
  
  
  METHODS
  From a group of 97 patients, 32 patients with hepatic fat fraction greater than 5%, as measured by MRS, were identified. In these patients, chemical shift encoded fat-water imaging was performed, covering the entire liver in a single breathhold. Fat fraction was measured from the imaging data by postprocessing using 6 different models: single- and dual-R(2)* correction, each performed with complex fitting, magnitude fitting, and mixed magnitude/complex fitting to compare the effects of phase error correction. Fat fraction measurements were compared with co-registered spectroscopy measurements using linear regression.
  
  
  RESULTS
  Linear regression demonstrated higher agreement with MRS using single-R(2)* correction compared with dual-R(2)* correction. Among single-R(2)* models, all 3 fittings methods performed similarly well (slope = 1.0 ± 0.06, r(2) = 0.89-0.91).
  
  
  CONCLUSIONS
  Single-R(2)* modeling is more accurate than dual-R(2)* modeling for hepatic fat quantification in patients, even in those with high hepatic fat concentrations.
authors.affiliation: Department of Radiology, University of Wisconsin, Madison, Wisconsin 53792-3252, USA.
authors.forename: Debra E
authors.initials: DE
authors.lastname: Horng
authors.forename: Diego
authors.initials: D
authors.lastname: Hernando
authors.forename: Catherine D G
authors.initials: CD
authors.lastname: Hines
authors.forename: Scott B
authors.initials: SB
authors.lastname: Reeder
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D050154:Adiposity; D000328:Adult; D000368:Aged; D000465:Algorithms; D016477:Artifacts; D005234:Fatty Liver / Q000473:pathology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity