Article History
Received: 12 April 2018
Accepted: 18 February 2019
First Online: 26 February 2019
Ethics approval and consent to participate
: The research protocol was approved by Seoul National University Bundang Hospital Institutional Review Board approval (IRB number: B-1704/390-106). Informed consent was waived for this study.
: Not applicable.
: The authors declare that they have no competing interests.
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