1Core Facility Small Animal MRI, Ulm University, Ulm, Germany, 2Target Discovery Research, In-vivo imaging laboratory, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany, 3Department of Neuroradiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany, 4Department of Internal Medicine II, Ulm University, Ulm, Germany