[1] Royal Melbourne Hosp, Dept Neurol, Parkville, Vic 3050, Australia
[2] Royal Melbourne Hosp, Dept Radiol, Parkville, Vic 3050, Australia
[3] Royal Melbourne Hosp, Dept Endocrinol & Diabet, Parkville, Vic 3050, Australia
[4] Austin & Repatriat Med Ctr, Dept Neurol, Parkville, Vic, Australia
[5] Univ Melbourne, Parkville, Vic 3052, Australia