[1] Vancouver Gen Hosp, Dept Pathol & Lab Med, Vancouver, BC, Canada
[2] Univ British Columbia, Dept Pathol & Lab Med, Vancouver, BC V5Z 1M9, Canada
[3] Univ British Columbia, Dept Phys & Astron, Vancouver, BC V5Z 1M9, Canada
[4] Univ British Columbia, Dept Radiol, Vancouver, BC V5Z 1M9, Canada
[5] Vancouver Gen Hosp, Dept Radiol, Vancouver, BC, Canada
[6] UBC Hosp, Vancouver, BC, Canada
[7] Vancouver Gen Hosp, Dept Med, Vancouver, BC, Canada
[8] UBC Hosp, Multiple Sclerosis Clin, Vancouver, BC, Canada