[1] RWTH Aachen Univ Hosp, Dept Diagnost & Intervent Neuroradiol, Pauwelsstr 30, D-52074 Aachen, Germany
[2] RWTH Aachen Univ Hosp, Dept Neurosurg, Aachen, Germany
[3] RWTH Aachen Univ Hosp, Dept Neurol, Aachen, Germany
[4] Justus Liebig Univ Giessen, Dept Neurosurg, Giessen, Germany
[5] Justus Liebig Univ Giessen, Inst Med Informat, Med Stat, Giessen, Germany
[6] Paracelsus Kliniken, Dept Neurosurg, Osnabruck, Germany