[1] Univ Calgary, Dept Diagnost Imaging, Foothills Hosp, Calgary, AB T2N 4N2, Canada
[2] Univ Calgary, Dept Clin Neurosci, Foothills Hosp, Calgary, AB T2N 4N2, Canada
[3] Univ Calgary, Dept Anat, Foothills Hosp, Calgary, AB T2N 4N2, Canada
[4] Alberta Stroke Program, Calgary, AB, Canada