Paolo Lombardo1, Knud Nairz1, Ingrid Boehm2. 1. Department of Diagnostic, Interventional, and Pediatric Radiology, University of Bern, Inselspital, Bern, Switzerland. 2. Department of Diagnostic, Interventional, and Pediatric Radiology, University of Bern, Inselspital, Bern, Switzerland. Electronic address: Ingrid.boehm@insel.ch.