title: Direct Determination of Lean Body Mass by CT in F-18 FDG PET/CT Studies: Comparison with Estimates Using Predictive Equations.
abstract: OBJECTIVE
  The purpose of this study was to estimate lean body mass (LBM) using CT (LBM CTs) and compare the results with LBM estimates of four different predictive equations (LBM PEs) to assess whether LBM CTs and LBM PEs can be used interchangeably for SUV normalization.
  
  
  METHODS
  Whole-body F-18 FDG PET/CT studies were conducted on 392 patients. LBM CT1 is modified adipose tissue-free body mass, and LBM CT2 is adipose tissue-free body mass. Four different PEs were used for comparison (LBM PE1-4). Agreement between the two measurement methods was assessed by Bland-Altman analysis. We calculated the difference between two methods (bias), the percentage of difference, and the limits of agreement, expressed as a percentage.
  
  
  RESULTS
  For LBM CTs vs. LBM PEs, except LBM PE3, the ranges of biases and limits of agreement were -3.77 to 3.81 kg and 26.60-35.05 %, respectively, indicating the wide limits of agreement and differing magnitudes of bias. For LBM CTs vs. LBM PE3, LBM PE3 had wider limits of agreement and greater positive bias (44.28-46.19 % and 10.49 to 14.04 kg, respectively), showing unacceptably large discrepancies between LBM CTs and LBM PE3.
  
  
  CONCLUSIONS
  This study demonstrated that there are substantial discrepancies between individual LBM CTs and LBM PEs, and this should be taken into account when LBM CTs and LBM PEs are used interchangeably between patients.
authors.affiliation: Department of Nuclear Medicine, Wonkwang University School of Medicine, 344-2 Shinyong-Dong, Iksan, 570-711 Korea ; Institute of Wonkwang Medical Science, 344-2 Shinyong-Dong, Iksan, 570-711 Korea.
authors.forename: Chang Guhn
authors.initials: CG
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Wonkwang University School of Medicine, 344-2 Shinyong-Dong, Iksan, 570-711 Korea.
authors.forename: Woo Hyoung
authors.initials: WH
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Wonkwang University School of Medicine, 344-2 Shinyong-Dong, Iksan, 570-711 Korea.
authors.forename: Myoung Hyoun
authors.initials: MH
authors.lastname: Kim
authors.affiliation: Department of Nuclear Medicine, Wonkwang University School of Medicine, 344-2 Shinyong-Dong, Iksan, 570-711 Korea ; Institute of Wonkwang Medical Science, 344-2 Shinyong-Dong, Iksan, 570-711 Korea.
authors.forename: Dae-Weung
authors.initials: DW
authors.lastname: Kim
keywords: Adipose tissue; Body composition; Computed tomography; Lean body mass; Positron emission tomography