1 Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kings Highway Blvd Campus Box 8131, St Louis, MO, 63110, USA. davidballard@wustl.edu.
2 Department of Radiology, LSUHSC-Shreveport, 1501 Kings Highway, Shreveport, LA, 71103, USA.
3 Department of Orthopaedic Surgery, LSUHSC-Shreveport, 1501 Kings Highway, Shreveport, LA, 71103, USA.