1. From the Neurosurgery Research Group (J.F., A. Piippo, A. Paetau, M.K., M.N., J.H., J.J.), Biomedicum Helsinki, Helsinki, Finland; the Departments of Neurosurgery (J.F., A. Piippo, M.N., J.H.) and Pathology (A. Paetau), and the Medical Imaging Center (M.K.), Helsinki University Central Hospital, Helsinki, Finland; and the Department of Neurosurgery (J.J.), Kuopio University Hospital, Kuopio, Finland.