1. From the Department of Radiology, Radiology Informatics Laboratory (P.R., J.C.C., Q.H., K.Z., B.J.E.), Department of Health Sciences Research (C.C.W., T.R., M.J.T., H.M.K.), Department of Orthopedic Surgery (C.C.W., T.R., M.J.T., H.M.K.), Department of Clinical Anatomy (C.C.W.), and Mayo Clinic Alix School of Medicine (S.J.K.), Mayo Clinic, 200 First St SW, Rochester, MN 55905.