1Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polythechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 2Universitätsklinikum Münster, Münster, Germany, 3Center for Biomedical Imaging (CIBM) and Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 4Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland