[1] Univ Helsinki, Cent Hosp, Dept Neurol, FIN-00014 Helsinki, Finland
[2] Univ Helsinki, Cent Hosp, Dept Radiol, FIN-00014 Helsinki, Finland
[3] Univ Helsinki, Cent Hosp, Program Neurosci, FIN-00014 Helsinki, Finland
[4] Univ Helsinki, Cent Hosp, Biomedicum, Helsinki Emergency Med Serv, FIN-00014 Helsinki, Finland