1. Computer Graphics and Multimedia Systems Group; University of Siegen; Germany
2. Department of Neurosurgery; University Hospital Motol; Prague Czech Republic
3. International Clinical Research Center; St. Anne's University Hospital Brno; Brno Czech Republic
4. Department of Neurosurgery; University Hospital Gießen and Marburg; Marburg Germany
5. Department of Neurosurgery; Jan Evangelista PurkyněUniversity; Ústí nad Labem Czech Republic