Funding for this research was provided by:
University of Texas Southwestern Medical Center
Received: 3 January 2018
Accepted: 5 February 2018
First Online: 20 February 2018
Ethics approval and consent to participate
: The study was approved by the UT Southwestern Medical Center institutional review board (IRB). Given the retrospective, non-invasive nature of the study and a minimal potential for harm to study participants, the informed consent requirement was waived by the IRB.
: No individually identifiable patient data is presented in this report.
: The authors declare that they have no competing interests.
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