1. Department of Thoracic and Cardiovascular Surgery, West-German Heart and Vascular Center Essen, University Hospital Essen, Essen, Germany
2. Chair of Mechanics and Robotics, University Duisburg-Essen, Campus Duisburg, Lotharstraße 1, 47057 Duisburg, Germany
3. Institute for Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany