Funding for this research was provided by:
The Chinese Ultrasound Doctors Association (KJXX2019002, KJXX2019002, KJXX2019002, KJXX2019002)
Article History
Received: 28 August 2019
Accepted: 11 December 2019
First Online: 9 January 2020
Supplementary information
:
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee (the ethics committee of the China–Japan Union Hospital of Jilin University) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: The need for individual consent was waived by the committee.