1. Division
of Image Processing, Department of Radiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
2. Department
of Neurosurgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, United States
3. Computer
Graphics and Visualization Group, Faculty of EEMCS, Delft University of Technology, 2628 CN Delft, The Netherlands
4. Fondazione Pisana per la Scienza ONLUS, 56121 Pisa, Italy