From the Divisions of Neurosurgery (G.B.A., D.E.S., J.M.F.) and Diagnostic Imaging (R.A., R.F.), University of Alberta, Edmonton, Alberta, Canada. Correspondence to J. Max Findlay, MD, Division of Neurosurgery, 2D1.02 WMC, University of Alberta, 8440 112 St, Edmonton, Alberta, Canada T6G 2B7. (At 2000-09)