Received: 24 March 2021
Accepted: 31 August 2021
First Online: 15 September 2021
: We conducted this study according to the ethical guidelines of our institution (approval by the research ethics committee of the University of Tsukuba: 1527) in accordance with the principles of the Declaration of Helsinki. The requirement for informed patient consent was waived because of the anonymous nature of the data by the ethics committee of the University of Tsukuba.
: Not applicable.
: Fast DOCTOR Ltd. sponsored RI’s joint appointment as an associate professor at the University of Tsukuba. Fast DOCTOR Ltd. also sponsored KM’s XJ’s appointment as an assistant professor at the University of Tsukuba. IM and NT have no conflict of interest.