Subjects and methods
The present study was conducted according to the tenets of the Declaration of Helsinki. The research protocol and informed consent/assent forms were approved by the institutional review board of Yokohama City University Hospital, and Kanagawa Children’s Medical Center. Written informed consent was obtained from each parent or guardian of the patients included in the study as well as patients aged more than 6 years who were capable of understanding the purpose of this study. Informed consent for publication of identifying information/images in an online open-access publication was also obtained from all patients and/or their legal guardian. This study was supervised by an independent data and safety monitoring committee. This study is available on the website of UMIN Clinical Trial Registry (