Text and Data Mining valid from 2018-05-14
Received: 30 January 2018
Revised: 10 April 2018
Accepted: 18 April 2018
First Online: 14 May 2018
Compliance with ethical standards
: The scientific guarantor of this publication is Koichiro Yasaka.
: The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.
: No complex statistical methods were necessary for this paper.
: Written informed consent was waived by the institutional review board.
: Institutional review board approval was obtained.
: • retrospective• diagnostic or prognostic study• performed at one institution