Received: 26 February 2018
Accepted: 24 July 2018
First Online: 5 September 2018
Ethics approval and consent to participate
: All procedures involving human participants were in accordance with the ethical standards of the institution at which the studies were conducted with approval from the Tohoku University Hospital Review Board (IRB no. 2011-120-1) on June 10, 2011, and the Tsukuba University of Technology Review Board (IRB no. 05/02/2015) on February 5, 2015. This protocol was also retrospectively registered with the UMIN Clinical Trials Registry (UMIN-CTR R 000032202) on April 11, 2018. The study was conducted in compliance with the standards of the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from the patients to participate in this study.
: Not applicable.
: The authors declare that they have no competing interests.
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