[1] Univ North Carolina Chapel Hill, Biomed Res Imaging Ctr, CB 7513, Chapel Hill, NC 27599 USA
[2] Taipei Vet Gen Hosp, Dept Radiol, Taipei 11217, Taiwan
[3] Univ N Carolina, Sch Med, Dept Radiol, Neuroradiol Sect, CB 7510,511 Old Infirm, Chapel Hill, NC 27599 USA
[4] Univ N Carolina, Sch Med, Div Nucl Med, Lineberger Comprehens Canc Ctr, CB 7510,Phys Off Bldg B119, Chapel Hill, NC 27599 USA