[1] Leeds Teaching Hosp, Chapel Allerton Hosp, Musculoskeletal Ctr, Dept Radiol, Leeds LS7 4SA, W Yorkshire, England
[2] Chapel Allerton Hosp, Natl Inst Hlth Res, Leeds Biomed Res Ctr, Leeds, W Yorkshire, England
[3] Univ Washington, Dept Radiol, Seattle, WA 98195 USA
[4] Univ Calif Los Angeles, David Geffen Sch Med, Dept Radiol Sci, Los Angeles, CA 90095 USA
[5] Univ Michigan, Med Ctr, Dept Radiol, Ann Arbor, MI 48109 USA