1. From the University Institute of Diagnostic and Interventional Neuroradiology (T.D., P.J.M., F.Z., P.M., J.G., E.I.P.) and Department of Neurosurgery (A.R., C.T.U., J.B.), University of Bern, Inselspital, Freiburgstrasse 8, Bern 3010, Switzerland.