1. Institute of Inorganic and Analytical Chemistry, University of Münster , Münster, Germany
2. Division of Internal Medicine, Universitätsspital and University of Zurich , Zurich , Switzerland
3. Department of Neurosurgery, Clinical Neuroscience Center, Universitätsspital and University of Zurich , Zurich , Switzerland
4. Diagnostic Imaging Research Unit, Clinic for Diagnostic Imaging, University of Zurich , Zurich , Switzerland