Article History
First Online: 21 May 2019
Compliance with ethical standards
:
: This was not an industry supported study. The authors have no commercial, financial, or otherrelationship related to the subject of this paper that could constitute or suggest a conflict ofinterest.
: All procedures performed in studies involving human participants were in accordance withthe ethical standards of the Institutional Review Board of the Samsung Medical Center.
: Informed consent was obtained from all individual participants included in the study.