[1] Penn State Univ, Milton S Hershey Med Ctr, Coll Med, Dept Radiol,Ctr NMR Res, Hershey, PA 17033 USA
[2] Penn State Univ, Milton S Hershey Med Ctr, Coll Med, Dept Cellular & Mol Physiol, Hershey, PA 17033 USA
[3] Univ Cincinnati, Childrens Hosp Res Fdn, Imaging Res Ctr, Dept Pediat, Cincinnati, OH 45221 USA
[4] Univ Cincinnati, Childrens Hosp Res Fdn, Imaging Res Ctr, Dept Radiol, Cincinnati, OH 45221 USA