[1] Univ Utah, Dept Pediat, Neonatol Div, Salt Lake City, UT 84113 USA
[2] Univ Utah, Dept Radiol & Imaging Sci, Salt Lake City, UT 84113 USA
[3] Loma Linda Univ, Sch Med, Dept Pediat, Div Neonatol, Loma Linda, CA 92354 USA
[4] Univ Southern Calif USC, Dept Pediat, Div Neonatol, Los Angeles, CA 90007 USA