1. Department of Radiology, University Hospital Jena, Am Klinikum 1, Jena 07747, Germany e-mail:
2. Department of Radiology, Charité University Hospital, Charitépl. 1, Berlin 10117, Germany
3. Department of Radiology, Charité University Hospital, Charitépl. 1, Berlin 10117, Germany e-mail: