[1] Johns Hopkins Sch Med, Dept Radiol, Baltimore, MD USA
[2] Johns Hopkins Sch Med, Dept Surg, Baltimore, MD USA
[3] Johns Hopkins Sch Med, Dept Oncol, Baltimore, MD USA
[4] Northwestern Univ, Dept Radiol, Chicago, IL 60611 USA
[5] Univ Colorado, Ctr Canc, Dept Oncol, Aurora, CO USA
[6] Northwestern Univ, Dept Oncol, Chicago, IL 60611 USA