1. Stroke Unit, Department of Acute Medicine Queen's Medical Centre, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
2. Stroke Trials Unit, University of Nottingham, Nottingham, United Kingdom
3. Department of Neurosurgery, Queen's Medical Centre, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
4. Department of Neurology, Neurosurgery and Radiology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts
5. Department of Neurosurgery, King's College Hospitals NHS Foundation Trust, London, United Kingdom