1. From the Departments of Radiology (B.M., M.K., M.M., J.T.), Orthopedic Surgery (S.C.), and Neurological Surgery (A.B.C., E.K.O.), Mount Sinai Health System, 1468 Madison Ave, Annenberg Building, 8th Floor, New York, NY 10029; and Department of Medicine, California Pacific Medical Center, San Francisco, Calif (J.R.Z.).