1 Department of Neurosurgery, John Radcliffe Hospital, Oxford University Hospitals NHS Trust, Oxford, United Kingdom. Electronic address: Puneet.Plaha@ouh.nhs.uk.
2 Department of Neurosurgery, John Radcliffe Hospital, Oxford University Hospitals NHS Trust, Oxford, United Kingdom.
3 Oxford Centre for MRI of the Brain, Nuffield Department of Clinical Neuroscience, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.