1. From the Departments of Vascular Medicine (R.D., E.d.G., B.M.E., E.S.S., J.J.P.K.) and Radiology (J.S.L., A.J.N.), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and the Department of Radiology (R.J.v.d.G.), Leiden University Medical Center, Leiden, The Netherlands.