Text and Data Mining valid from 2019-04-18
Received: 28 October 2018
Accepted: 2 April 2019
First Online: 18 April 2019
Ethics approval and consent to participate
: This study was approved by Institutional review board approval for Severance Hospital (IRB IRB 4-2017-1219). The need for informed consent was waived.
: Not applicable
: The authors declare that they have no competing interests.
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