title: International Consensus for ultrasound lesions in gout: results of Delphi process and web-reliability exercise.
abstract: OBJECTIVE
  To produce consensus-based definitions of the US elementary lesions in gout and to test their reliability in a web-based exercise.
  
  
  METHODS
  The process consisted of two steps. In the first step a written Delphi questionnaire was developed from a systematic literature review and expert international consensus. This collated information resulted in four statements defining US elementary lesions: double contour (DC), tophus, aggregates and erosion. The Delphi questionnaire was sent to 35 rheumatology experts in US, asking them to rate their level of agreement or disagreement with each statement. The second step tested the reliability by a web-exercise. US images of both normal and gouty elementary lesions were collected by the participants. A facilitator then constructed an electronic database of 110 images. The database was sent to the participants, who evaluated the presence/absence of US elementary lesions. A group of 20 images was displayed twice to evaluate intra-reader reliability.
  
  
  RESULTS
  A total of 32 participants responded to the questionnaires. Good agreement (>80%) was obtained for US definitions on DC, tophus, aggregates and erosion in the Delphi exercise after three rounds. The reliability on images showed inter-reader κ values for DC, tophus, aggregates, erosion findings of 0.98, 0.71, 0.54 and 0.85, respectively. The mean intra-reader κ values were also acceptable: 0.93, 0.78, 0.65 and 0.78, respectively.
  
  
  CONCLUSIONS
  This, the first consensus-based US definition of elementary lesions in gout, demonstrated good reliability overall. It constitutes an essential step in developing a core outcome measurement that permits a higher degree of homogeneity and comparability between multicentre studies.
authors.affiliation: Rheumatology Department, Clinica Reumatologica, Università Politecnica delle Marche, Jesi, Ancona, Italy, dr.gmarwin@gmail.com.
authors.forename: Marwin
authors.initials: M
authors.lastname: Gutierrez
authors.affiliation: Rheumatology Department, Immanuel Krankenhaus, Medical Centre for Rheumatology, Berlin, Germany.
authors.forename: Wolfgang A
authors.initials: WA
authors.lastname: Schmidt
authors.affiliation: Department of Medicine, Allergy/Immunology and Rheumatology Division, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.
authors.forename: Ralf G
authors.initials: RG
authors.lastname: Thiele
authors.affiliation: School of Medicine and Pharmacology Fiona Stanley Hospital Unit, University of Western Australia, Perth, Australia.
authors.forename: Helen I
authors.initials: HI
authors.lastname: Keen
authors.affiliation: Division of Rheumatology, University of Florida College of Medicine, Jacksonville, FL, USA.
authors.forename: Gurjit S
authors.initials: GS
authors.lastname: Kaeley
authors.affiliation: Rheumatology Department, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors.forename: Esperanza
authors.initials: E
authors.lastname: Naredo
authors.affiliation: Dipartimento di Medicina Interna e Specialità Mediche, Sapienza Università di Roma, Rome.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Iagnocco
authors.affiliation: Rheumatology Department, MC Groep Hospitals, Lelystad, Netherlands.
authors.forename: George A
authors.initials: GA
authors.lastname: Bruyn
authors.affiliation: 3rd Rheumatology Department, National Institute of Rheumatology and Physiotherapy, Budapest, Hungary.
authors.forename: Peter V
authors.initials: PV
authors.lastname: Balint
authors.affiliation: Rheumatology Department, Clinica Reumatologica, Università Politecnica delle Marche, Jesi, Ancona, Italy.
authors.forename: Emilio
authors.initials: E
authors.lastname: Filippucci
authors.affiliation: Division of Rheumatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Mandl
authors.affiliation: Rheumatology Department, Trinity College, Dublin, Ireland.
authors.forename: David
authors.initials: D
authors.lastname: Kane
authors.affiliation: Rheumatology Department, Instituto Nacional de Rehabilitacion, Mexico City, Mexico.
authors.forename: Carlos
authors.initials: C
authors.lastname: Pineda
authors.affiliation: Rheumatology Unit, University of Pisa, Pisa, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Delle Sedie
authors.affiliation: Rheumatology Department, Diakonhjemmet Hospital, Oslo, Norway.
authors.forename: Hilde Berner
authors.initials: HB
authors.lastname: Hammer
authors.affiliation: Musculoskeletal Statistics Unit, The Parker Institute, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark.
authors.forename: Robin
authors.initials: R
authors.lastname: Christensen
authors.affiliation: INSERM U1173, Rheumatology Department, Laboratoire d'excellence INFLAMEX, UFR Simone Veil, Versailles-Saint-Quentin University, Saint-Quentin en Yvelines, France and.
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: D'Agostino
authors.affiliation: Rheumatology Department, Center for Rheumatology and Spine diseases, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Lene
authors.initials: L
authors.lastname: Terslev
mesh_terms: D003697:Delphi Technique; D003952:Diagnostic Imaging / Q000379:methods; D006073:Gout / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D006801:Humans; D020407:Internet; D015588:Observer Variation; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D009626:Terminology as Topic; D014463:Ultrasonography
keywords: Delphi process; elementary lesions; gout; ultrasound; web reliability