1 Institute of Neuroscience and Medicine, Forschungszentrum Jülich, Jülich, Germany; Department of Nuclear Medicine, University of Aachen, Aachen, Germany. Electronic address: k.j.langen@fz-juelich.de.
2 Department of Neurosurgery, University of Munich, Munich, Germany.
3 Department of Nuclear Medicine, University of Munich, Munich, Germany.
4 Institute of Neuroscience and Medicine, Forschungszentrum Jülich, Jülich, Germany; Department of Neurology, University of Cologne, Cologne, Germany.