1. From Siemens Healthcare, An der Laende 1, 91301 Forchheim, Germany (T.N., B.S.); Institute of Diagnostic and Interventional Radiology (M.E., N.S., H.A., A.E.) and Department of Rheumatology (D.F., O.D.), University Hospital Zurich, University of Zurich, Raemistrasse 100, 8091 Zurich, Switzerland.