1. Department of Epidemiology & Biostatistics (R.V., M.H., M.M.B.B., D.A.M. van der K., A.H., J.C.M.W.) and Department of Radiology, Daniel den Hoed Clinic (M.O.), Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands, and Department of Radiology, State University Groningen/Academic Hospital Groningen, Groningen, The Netherlands (M.O., R.V.).