[1] Washington Univ, Dept Neurosurg, 660 South Euclid Ave,Campus Box 8057, St Louis, MO 63110 USA
[2] George Washington Univ, Biostat Ctr, Dept Biostat & Bioinformat, 6110 Execut Blvd,Suite 750, Rockville, MD 20852 USA
[3] Weill Cornell Med Coll, Dept Neurosurg, 525 East 68th St,Whitney 6,Box 99, New York, NY 10065 USA
[4] Cornell Tech, Dept Operat Res & Informat Engn, 2 West Loop Rd, New York, NY 10044 USA