1. Institute of Diagnostic Radiology at the Asklepios Klinik Pasewalk, Academic Teaching Hospital of the University of Greifswald, Pasewalk, Germany.
2. Institute of Diagnostic and Interventional Radiology/Neuroradiology, Westkuestenklinikum Heide, Academic Teaching Hospital of the Universities of Kiel, Luebeck and Hamburg, Heide, Germany.