[1] Univ Texas MD Anderson Canc, Dept Diagnost Radiol, 1515 Holcombe Blvd,Unit 1473, Houston, TX 77030 USA
[2] NCI, Harris Tech Serv Corp, NIH, Bethesda, MD 20892 USA
[3] NCI, Ctr Canc Res, NIH, Bethesda, MD 20892 USA
[4] Univ Texas MD Anderson Canc Ctr, Dept Canc Syst Imaging, Houston, TX 77030 USA