1. Department of Neuroradiology, Vascular and Interventional Radiology, Medical University Graz, Auenbruggerplatz 9, Graz 8036, Austria
2. Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, Graz 8010, Austria
3. Institute of Solid State Physics, Friedrich Schiller University Jena, Helmholtzweg 5, Jena 07743, Germany