title: Large-vessel vasculitis: interobserver agreement and diagnostic accuracy of 18F-FDG-PET/CT.
abstract: BACKGROUND
  (18)F-FDG-PET visualises inflammation. Both atherosclerosis and giant cell arteritis cause vascular inflammation, but distinguishing the two may be difficult. The goal of this study was to assess interobserver agreement and diagnostic accuracy of (18)F-FDG-PET for the detection of large artery involvement in giant cell arteritis (GCA).
  
  
  METHODS
  31 (18)F-FDG-PET/CT scans were selected from 2 databases. Four observers assessed vascular wall (18)F-FDG uptake, initially without and subsequently with predefined observer criteria (i.e., vascular wall (18)F-FDG uptake compared to liver or femoral artery (18)F-FDG uptake). External validation was performed by two additional observers. Sensitivity and specificity of (18)F-FDG-PET were determined by comparing scan results to a consensus diagnosis.
  
  
  RESULTS
  The highest interobserver agreement (kappa: 0.96 in initial study and 0.79 in external validation) was observed when vascular wall (18)F-FDG uptake higher than liver uptake was used as a diagnostic criterion, although agreement was also good without predefined criteria (kappa: 0.68 and 0.85). Sensitivity and specificity were comparable for these methods. The criterion of vascular wall (18)F-FDG uptake equal to liver (18)F-FDG uptake had low specificity.
  
  
  CONCLUSIONS
  Standardization of image assessment for vascular wall (18)F-FDG uptake promotes observer agreement, enables comparative studies, and does not appear to result in loss of diagnostic accuracy compared to nonstandardized assessment.
authors.affiliation: Department of Internal Medicine and Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, 1007 MB Amsterdam, Netherlands.
authors.forename: K D F
authors.initials: KD
authors.lastname: Lensen
authors.affiliation: Department of Nuclear Medicine and Radiology, VU University Medical Center, 1007 MB Amsterdam, Netherlands.
authors.forename: E F I
authors.initials: EF
authors.lastname: Comans
authors.affiliation: Department of Rheumatology, VU University Medical Center, 1007 MB Amsterdam, Netherlands.
authors.forename: A E
authors.initials: AE
authors.lastname: Voskuyl
authors.affiliation: Department of Rheumatology, VU University Medical Center, 1007 MB Amsterdam, Netherlands.
authors.forename: C J
authors.initials: CJ
authors.lastname: van der Laken
authors.affiliation: Department of Rheumatology, University Medical Center Groningen, 9700 RB Groningen, Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Brouwer
authors.affiliation: Department of Nuclear Medicine, Spaarne Hospital, 2130 AT Hoofddorp, Netherlands.
authors.forename: A T
authors.initials: AT
authors.lastname: Zwijnenburg
authors.affiliation: Department of Nuclear Medicine, Rijnland Hospital, 2350 CC Leiderdorp, Netherlands.
authors.forename: L M
authors.initials: LM
authors.lastname: Pereira Arias-Bouda
authors.affiliation: Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, 9700 RB Groningen, Netherlands.
authors.forename: A W J M
authors.initials: AW
authors.lastname: Glaudemans
authors.affiliation: Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, 9700 RB Groningen, Netherlands.
authors.forename: R H J A
authors.initials: RH
authors.lastname: Slart
authors.affiliation: Department of Internal Medicine and Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, 1007 MB Amsterdam, Netherlands.
authors.forename: Y M
authors.initials: YM
authors.lastname: Smulders
mesh_terms: D000368:Aged; D001158:Arteries / Q000473:pathology*; D050197:Atherosclerosis / Q000175:diagnosis / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D013700:Giant Cell Arteritis / Q000175:diagnosis / Q000473:pathology; D006801:Humans; D007249:Inflammation / Q000175:diagnosis / Q000473:pathology; D008297:Male; D015588:Observer Variation; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods; D014657:Vasculitis / Q000175:diagnosis* / Q000473:pathology
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18