[1] Univ Florida, Shands Hosp, Dept Neurol, Gainesville, FL 32610 USA
[2] Univ Florida, Shands Hosp, Dept Neurosurg, Gainesville, FL 32610 USA
[3] Univ Florida, Shands Hosp, Dept Radiol, Gainesville, FL 32610 USA
[4] Univ Louisville, Dept Med, Hlth Care Ctr, Louisville, KY 40292 USA