[1] Copenhagen Univ Hosp, Neurovasc Sect, Dept Radiol, Rigshosp, Blegdamsvej 9, DK-2100 Copenhagen, Denmark
[2] Copenhagen Univ Hosp, Dept Neurol, Rigshosp, Copenhagen, Denmark
[3] Rigshosp, Sect Transfus Med, Capital Reg Blood Bank, Copenhagen, Denmark
[4] Copenhagen Univ Hosp, Dept Anesthesiol, Ctr Head & Orthoped, Copenhagen, Denmark
[5] Copenhagen Univ Hosp, Dept Neuroanesthesiol, Rigshosp, Copenhagen, Denmark