title: A comparative study of software programmes for cross-sectional skeletal muscle and adipose tissue measurements on abdominal computed tomography scans of rectal cancer patients.
abstract: BACKGROUND
  The association between body composition (e.g. sarcopenia or visceral obesity) and treatment outcomes, such as survival, using single-slice computed tomography (CT)-based measurements has recently been studied in various patient groups. These studies have been conducted with different software programmes, each with their specific characteristics, of which the inter-observer, intra-observer, and inter-software correlation are unknown. Therefore, a comparative study was performed.
  
  
  METHODS
  Fifty abdominal CT scans were randomly selected from 50 different patients and independently assessed by two observers. Cross-sectional muscle area (CSMA, i.e. rectus abdominis, oblique and transverse abdominal muscles, paraspinal muscles, and the psoas muscle), visceral adipose tissue area (VAT), and subcutaneous adipose tissue area (SAT) were segmented by using standard Hounsfield unit ranges and computed for regions of interest. The inter-software, intra-observer, and inter-observer agreement for CSMA, VAT, and SAT measurements using FatSeg, OsiriX, ImageJ, and sliceOmatic were calculated using intra-class correlation coefficients (ICCs) and Bland-Altman analyses. Cohen's κ was calculated for the agreement of sarcopenia and visceral obesity assessment. The Jaccard similarity coefficient was used to compare the similarity and diversity of measurements.
  
  
  RESULTS
  Bland-Altman analyses and ICC indicated that the CSMA, VAT, and SAT measurements between the different software programmes were highly comparable (ICC 0.979-1.000, P < 0.001). All programmes adequately distinguished between the presence or absence of sarcopenia (κ = 0.88-0.96 for one observer and all κ = 1.00 for all comparisons of the other observer) and visceral obesity (all κ = 1.00). Furthermore, excellent intra-observer (ICC 0.999-1.000, P < 0.001) and inter-observer (ICC 0.998-0.999, P < 0.001) agreement for all software programmes were found. Accordingly, excellent Jaccard similarity coefficients were found for all comparisons (mean ≥ 0.964).
  
  
  CONCLUSIONS
  FatSeg, OsiriX, ImageJ, and sliceOmatic showed an excellent agreement for CSMA, VAT, and SAT measurements on abdominal CT scans. Furthermore, excellent inter-observer and intra-observer agreement were achieved. Therefore, results of studies using these different software programmes can reliably be compared.
authors.affiliation: Department of Surgery, Erasmus MC University Medical Centre, Rotterdam, the Netherlands.
authors.forename: Jeroen L A
authors.initials: JL
authors.lastname: van Vugt
authors.affiliation: Department of Surgery, Erasmus MC University Medical Centre, Rotterdam, the Netherlands.
authors.forename: Stef
authors.initials: S
authors.lastname: Levolger
authors.affiliation: Department of Surgery, Erasmus MC University Medical Centre, Rotterdam, the Netherlands.
authors.forename: Arvind
authors.initials: A
authors.lastname: Gharbharan
authors.affiliation: Department of Radiology and Medical Informatics, Erasmus MC University Medical Centre, Rotterdam, the Netherlands.
authors.forename: Marcel
authors.initials: M
authors.lastname: Koek
authors.affiliation: Department of Radiology and Medical Informatics, Erasmus MC University Medical Centre, Rotterdam, the Netherlands.|Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands.
authors.forename: Wiro J
authors.initials: WJ
authors.lastname: Niessen
authors.affiliation: Department of Surgical Oncology, Erasmus MC - Daniel den Hoed Cancer Institute, Rotterdam, the Netherlands.
authors.forename: Jacobus W A
authors.initials: JW
authors.lastname: Burger
authors.affiliation: Department of Biostatistics, Erasmus MC University Medical Centre, Rotterdam, the Netherlands.
authors.forename: Sten P
authors.initials: SP
authors.lastname: Willemsen
authors.affiliation: Department of Surgery, Erasmus MC University Medical Centre, Rotterdam, the Netherlands.
authors.forename: Ron W F
authors.initials: RW
authors.lastname: de Bruin
authors.affiliation: Department of Surgery, Erasmus MC University Medical Centre, Rotterdam, the Netherlands.
authors.forename: Jan N M
authors.initials: JN
authors.lastname: IJzermans
mesh_terms: D000005:Abdomen; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D050152:Intra-Abdominal Fat / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D015588:Observer Variation; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging*; D012984:Software; D050151:Subcutaneous Fat / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed
keywords: Adipose tissue mass; Body composition; Comparability; Computed tomography; Skeletal muscle mass; Software