[1] Univ Calgary, Dept Clin Neurosci, Calgary, AB, Canada
[2] Natl Taiwan Univ Hosp, Dept Neurol, Taipei, Taiwan
[3] Univ Hosp Tours, Diagnost & Intervent Neuroradiol Dept, Tours, France
[4] Univ Manitoba, Hlth Sci Ctr, Dept Internal Med, Neurol Div,Rady Fac Hlth Sci, Winnipeg, MB, Canada
[5] Royal Univ Hosp, Dept Neurosurg, Saskatoon, SK, Canada
[6] Foothills Med Ctr, Alberta Hlth Serv, Calgary, AB, Canada
[7] Univ Calgary, Hotchkiss Brian Inst, Calgary, AB, Canada
[8] Univ Calgary, Dept Radiol, Calgary, AB, Canada
[9] Univ Calgary, Cummings Sch Med, Dept Clin Neurosci Radiol & Community Hlth Sci, 1403 29th St NW, Calgary, AB T2N 2T9, Canada