1. Rheumatology Unit, University of Pisa , Pisa, Italy
2. Department of Medical Biotechnologies, University of Siena , Siena, Italy
3. Radiology Unit, University of Pisa , Pisa, Italy
4. Cardiovascular Thoracic Department, University of Pisa , Pisa, Italy
5. Section of Statistics, University of Pisa , Pisa, Italy