title: Quantification of the fat fraction in the liver using dual-energy computed tomography and multimaterial decomposition.
abstract: OBJECTIVE
  The objective of this study was to evaluate the feasibility and accuracy of postcontrast, dual-energy computed tomography (DECT) using multimaterial decomposition (MMD) for quantification of the hepatic fat fraction (HFF).
  
  
  METHODS
  Various degrees of fatty liver were produced in 16 rabbits divided into 4 groups, by feeding them a high-fat, high-cholesterol diet. After 6 weeks, precontrast, single-energy computed tomography (SECT) and postcontrast DECT were performed, and HFF maps were obtained from the DECT using MMD. T2*-corrected, multiecho, chemical-shift imaging for obtaining the proton density fat fraction (PDFF) map and histologic assessment of the hepatic steatosis were also performed. The Pearson correlations coefficients were calculated, and Bland-Altman analysis was performed of the fat fractions determined by DECT, magnetic resonance imaging (MRI), and pathology. Receiver operating characteristic curve analysis was performed to detect 5% hepatic steatosis or greater. The histologic HFF was used as the reference standard, and PDFFs determined by chemical-shift imaging as the technical standard.
  
  
  RESULTS
  The HFFs calculated by MMD of postcontrast DECT scans were strongly correlated with those of pathology as well as the PDFFs of MRI (P < 0.05), and the mean differences of the Bland-Altman plots between the HFFs of DECT with MMD and the PDFFs of MRI were close to zero. The diagnostic performance of postcontrast DECT with MMD for detecting 5% hepatic steatosis or greater was comparable to that of the attenuation value of precontrast SECT and the PDFFs of MRI (P = 0.17-0.82).
  
  
  CONCLUSIONS
  Quantification of the HFF using postcontrast DECT with MMD was feasible and showed comparable sensitivity and specificity to the precontrast SECT for the detection of hepatic steatosis.
authors.affiliation: From the *Department of Radiology, SMG-SNU Boramae Medical Center; and †Department of Radiology, ‡Institute of Radiation Medicine, and §Department of Pathology, Seoul National University Hospital, Seoul, Korea.
authors.forename: Bo Yun
authors.initials: BY
authors.lastname: Hur
authors.forename: Jeong Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Woo
authors.initials: W
authors.lastname: Hyunsik
authors.forename: Kyung Bun
authors.initials: KB
authors.lastname: Lee
authors.forename: Ijin
authors.initials: I
authors.lastname: Joo
authors.forename: Joon Koo
authors.initials: JK
authors.lastname: Han
authors.forename: Byung Ihn
authors.initials: BI
authors.lastname: Choi
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging*; D000818:Animals; D005234:Fatty Liver / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D008297:Male; D011817:Rabbits; D015900:Radiography, Dual-Energy Scanned Projection; D014057:Tomography, X-Ray Computed / Q000379:methods