[1] St Anna Hosp, Herne, Germany
[2] DRK Kliniken Westend, Dept Clin Radiol, Herne, Germany
[3] Free Univ Berlin, UK Benjamin Franklin, Abt Rheumatol & Gastroenterol, D-1000 Berlin, Germany
[4] Deutsch Rheumaforschungzentrum, Berlin, Germany
[5] Univ Limburg, Dept Rheumatol, NL-6200 MD Maastricht, Netherlands
[6] Rheumazentrum Ruhrgebiet, Herne, Germany