[1] Department of Neuroradiology,
[2] University Hospital of the University of Technology,undefined
[3] Pauwelsstrasse 30,undefined
[4] 52057 Aachen,undefined
[5] Germany e-mail: tkrings@izkf.rwth-aachen.de Tel.: + 49-2 41-8 08 96 02 Fax: + 49-2 41-8 88 84 40,undefined
[6] Department of Neurosurgery,undefined
[7] University Hospital of the University of Technology,undefined
[8] Pauwelsstrasse 30,undefined
[9] 52057 Aachen,undefined
[10] Germany,undefined