Received: 21 April 2020
Accepted: 3 August 2020
First Online: 12 August 2020
Ethics approval and consent to participate
: This retrospective study was approved by the Asan Medical center institutional review board (IRB number: 2018–0670), which waived the requirement for patient consent.
: Not applicable. We removed details on individuals (etc. sex, age.) reported within the figure legend. We believe that consent for publication of images may not be required.
: The authors have no conflict of interest relevant to this study to declare.