[1] Mayo Clin, Dept Internal Med, Div Rheumatol, Rochester, MN 55905 USA
[2] Southend Univ Hosp, Dept Rheumatol, Westcliff On Sea, Essex, England
[3] Univ Genoa, Dept Internal Med, I-16126 Genoa, Italy
[4] Mayo Clin, Dept Hlth Sci Res, Rochester, MN USA
[5] Immanuel Krankenhaus Berlin, Med Ctr Rheumatol Berlin Buch Berlin, Dept Rheumatol, Berlin, Germany
[6] Innsbruck Med Univ, Dept Internal Med 1, Innsbruck, Austria
[7] Arcispedale S Maria Nuova, Dept Rheumatol, Reggio Emilia, Italy
[8] Mil Inst Med, Dept Rheumatol & Internal Med, Warsaw, Poland
[9] Med Univ Graz, Dept Rheumatol, Graz, Austria
[10] Gen Hosp Kufstein, Dept Internal Med, Kufstein, Austria
[11] Gentofte Univ Hosp, Div Rheumatol, Hellerup, Denmark
[12] Serv Med Interne, Amiens, France
[13] Natl Inst Rheumatism & Physiotherapy, Dept Radiol, Budapest, Hungary
[14] Natl Inst Rheumatism & Physiotherapy, Gen & Pediat Rheumatol Dept, Budapest, Hungary
[15] Univ Roma La Sapienza, Dipartimento Med Interna & Specialita Med, Rheumatol Unit, Rome, Italy
[16] Osped Misericordia & Dolce, Rheumatol Unit, Prato, Italy
[17] Hosp Clin Barcelona, Ctr Diag Imaging, Barcelona, Spain
[18] Univ Barcelona, Hosp Clin, Dept Syst Autoimmune Dis, Barcelona, Spain
[19] Univ Cantabria, Fac Med, Serv Reumatol, E-39005 Santander, Spain
[20] Sahlgrens Univ Hosp, Dept Rheumatol, Gothenburg, Sweden
[21] Marmara Univ, Sch Med, Dept Rheumatol, Istanbul, Turkey
[22] Princess Alexandra Hosp, Dept Rheumatol, Harlow, Essex, England
[23] Addenbrookes Hosp, Dept Rheumatol, Cambridge, England
[24] Univ Leeds, Rheumatol & Rehabil Res Unit, Leeds, W Yorkshire, England
[25] Univ Oxford, Nuffield Dept Orthopaed Rheumatol & Musculoskelet, Oxford, England
[26] Mayo Clin, Div Rheumatol, Dept Internal Med, Jacksonville, FL 32224 USA
[27] Rheumatol Associates N Jersey, Teaneck, NJ USA
[28] Mayo Clin, Div Rheumatol, Dept Internal Med, Scottsdale, AZ USA