1. Rheumatology Department, Betsi Cadwaladr University Health Board, Glan Clwyd Hospital, Bodelwyddan, Denbighshire, Wales LL18 5UJ, UK
2. Radiology Department, Polytechnic University of the Marche, 60020 Ancona, Italy
3. Rheumatology Department, Polytechnic University of the Marche, Jesi, 60035 Ancona, Italy