Received: 16 July 2018
Accepted: 18 December 2018
First Online: 8 January 2019
Ethics approval and consent to participate
: Ethics approval was given (Committee of the Medical Association of Rhineland-Palatinate, Mainz, Germany, reference no. 837.271.15), and participants in this study gave written consent to participate.
: Not applicable.
: PG and JF are paid members of an advisory board for Siemens. SV, KS, BS, MS, NB, and HK declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.