[1] Univ Hosp Freiburg, Dept Diagnost Radiol, D-79106 Freiburg, Germany
[2] Univ Hosp Freiburg, Dept Med Phys, D-79106 Freiburg, Germany
[3] Univ Hosp Freiburg, Dept Cardiovasc Surg, D-79106 Freiburg, Germany
[4] Univ Hosp Freiburg, Dept Neurophysiol, D-79106 Freiburg, Germany