[1] Childrens Natl Med Ctr, Div Diagnost Imaging & Radiol, Washington, DC 20010 USA
[2] Childrens Natl Med Ctr, Div Fetal & Transit Med, Washington, DC 20010 USA
[3] George Washington Univ, Sch Med & Hlth Sci, Dept Pediat, Washington, DC 20052 USA
[4] George Washington Univ, Sch Med & Hlth Sci, Dept Radiol, Washington, DC 20052 USA
[5] Stanford Univ, Dept Radiol, Stanford, CA 94305 USA
[6] Childrens Natl Med Ctr, Div Neonatol, Washington, DC 20010 USA
[7] Childrens Natl Med Ctr, Div Cardiol, Washington, DC 20010 USA