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Identification of calcium pyrophosphate deposition disease (CPPD) by ultrasound: reliability of the OMERACT definitions in an extended set of joints—an international multiobserver study by the OMERACT Calcium Pyrophosphate Deposition Disease Ultrasound Subtask Force
  1. Georgios Filippou1,
  2. Carlo Alberto Scirè1,
  3. Antonella Adinolfi2,
  4. Nemanja S Damjanov3,4,
  5. Greta Carrara4,
  6. George A W Bruyn5,
  7. Tomas Cazenave6,
  8. Maria Antonietta D’Agostino7,
  9. Andrea Delle Sedie8,
  10. Valentina Di Sabatino2,
  11. Mario Enrique Diaz Cortes9,
  12. Emilio Filippucci10,
  13. Frederique Gandjbakhch11,
  14. Marwin Gutierrez12,
  15. Daryl K Maccarter13,
  16. Mihaela Micu14,
  17. Ingrid Möller Parera15,
  18. Gaël Mouterde16,
  19. Mohamed Atia Mortada17,
  20. Esperanza Naredo18,
  21. Carlos Pineda12,
  22. Francesco Porta19,
  23. Anthony M Reginato20,
  24. Iulia Satulu21,
  25. Wolfgang A Schmidt22,
  26. Teodora Serban23,
  27. Lene Terslev24,
  28. Violeta Vlad25,
  29. Florentin Ananu Vreju26,
  30. Pascal Zufferey27,
  31. Panagiotis Bozios28,
  32. Carmela Toscano2,
  33. Valentina Picerno29,
  34. Annamaria Iagnocco23
  1. 1 Department of Medical Sciences, Section of Rheumatology, University of Ferrara and Azienda Ospedaliero-Universitaria Sant’Anna di Cona, Ferrara, Italy
  2. 2 University of Siena, Siena, Italy
  3. 3 University of Belgrade, Belgrade, Serbia
  4. 4 SIR Epidemiology Unit, Milan, Italy
  5. 5 Department of Rheumatology, MC Groep, Lelystad, The Netherlands
  6. 6 Instituto de Rehabilitación, Buenos Aires, Argentina
  7. 7 Université Versailles Saint-Quentin en Yvelines, Paris, France
  8. 8 University of Pisa, Pisa, Italy
  9. 9 Rheumatology Unit, University Hospital Fundación Santa Fe de Bogota, Bogota, Colombia
  10. 10 Università Politecnica delle Marche, Jesi, Italy
  11. 11 Department of Rheumatology, APHP, CHU Pitie-Salpetriere, Paris, France
  12. 12 Instituto Nacional de Rehabilitación, Mexico City, Mexico
  13. 13 North Valley Hospital, Whitefish, Montana, USA
  14. 14 Rehabilitation Clinical Hospital, Cluj-Napoca, Romania
  15. 15 Instituto Poal, University of Barcelona, Barcelona, Spain
  16. 16 Rheumatology department, Lapeyronie Hospital & EA 2415, Montpellier, France
  17. 17 Department of Rheumatology and Rehabilitation, Zagazig University, Zagazig, Egypt
  18. 18 Department of Rheumatology, Joint and Bone Research Unit, Hospital Universitario Fundación Jiménez Díaz and Autónoma University, Madrid, Spain
  19. 19 ASL 3, Pistoia, Italy
  20. 20 Division of Rheumatology, The Warren Alpert School of Medicine of Brown University, Providence, Rhode Island, USA
  21. 21 Department of Rheumatology, Internal Medicine Clinic, Kalmar County Hospital, Kalmar, Sweden
  22. 22 Immanuel Krankenhaus Berlin, Berlin, Germany
  23. 23 Rheumatology Unit, Università di Torino, Torino, Italy
  24. 24 Center for Rheumatology and Spine Diseases, Rigshospitalet, Copenhagen, Denmark
  25. 25 Sf. Maria HospitaL, Bucharest, Romania
  26. 26 Rheumatology Department, University of Medicine and Pharmacy Craiova, Craiova, Romania
  27. 27 Lausanne University Hospital, Lausanne, Switzerland
  28. 28 Department of Rheumatology, University of Ioannina, Ioannina, Greece
  29. 29 Rheumatology Department of Lucania, "San Carlo" Hospital of Potenza and "Madonna delle Grazie" Hospital of Matera, Potenza, Italy
  1. Correspondence to Dr Georgios Filippou, Department of Medical Sciences, Section of Rheumatology, University of Ferrara and Azienda Ospedaliero-Universitaria Sant’Anna di Cona, Ferrara 44124, Italy; gf.filippou{at}


Objectives To assess the reliability of the OMERACT ultrasound (US) definitions for the identification of calcium pyrophosphate deposition disease (CPPD) at the metacarpal-phalangeal, triangular fibrocartilage of the wrist (TFC), acromioclavicular (AC) and hip joints.

Methods A web-based exercise and subsequent patient-based exercise were carried out. A panel of 30 OMERACT members, participated at the web-based exercise by evaluating twice a set of US images for the presence/absence of CPPD. Afterwards, 19 members of the panel met in Siena, Italy, for the patient-based exercise. During the exercise, all sonographers examined twice eight patients for the presence/absence of CPPD at the same joints. Intraoberserver and interobserver kappa values were calculated for both exercises.

Results The web-based exercise yielded high kappa values both in intraobserver and interobserver evaluation for all sites, while in the patient-based exercise, inter-reader agreement was acceptable for the TFC and the AC. TFC reached high interobserver and intraobserver k values in both exercises, ranging from 0.75 to 0.87 (good to excellent agreement). AC reached moderate kappa values, from 0.51 to 0.85 (moderate to excellent agreement) and can readily be used for US CPPD identification.

Conclusions Based on the results of our exercise, the OMERACT US definitions for the identification of CPPD demonstrated to be reliable when applied to the TFC and AC. Other sites reached good kappa values in the web-based exercise but failed to achieve good reproducibility at the patient-based exercise, meaning the scanning method must be further refined.

  • chondrocalcinosis
  • ultrasonography
  • osteoarthritis

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  • Handling editor Josef S Smolen

  • Contributors Planning of the work: GF, CAS, AA, GC and AI. Conducting of the work: all authors. Reporting of the work: GF, CAS, NSD, GAWB, MAD, EF, IMP, EN, CP, AMR, LT and AI.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent Detail has been removed from this case description/these case descriptions to ensure anonymity. The editors and reviewers have seen the detailed information available and are satisfied that the information backs up the case the authors are making.

  • Ethics approval Comitato Etico di Area Vasta Sud-Est (siena).

  • Provenance and peer review Not commissioned; externally peer reviewed.

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