[1] Washington Univ, Sch Med, Mallinckrodt Inst Radiol, St Louis, MO 63110 USA
[2] Univ Washington, Sch Med, Div Pediat Cardiol, St Louis, MO USA
[3] Int Med Ctr, Dept Radiol, Tokyo, Japan
[4] Cincinnati Childrens Hosp, Ctr Med, Div Cardiol, Cincinnati, OH USA