1. Headache Division, Department of Neurology, University of Miami, Miller School of Medicine, USA
2. Department of Radiology and Imaging Sciences, Indiana University School of Medicine, USA
3. Department of Radiology and Biomedical Imaging, University of California, San Francisco, USA
4. Headache Group, Department of Neurology, University of California, San Francisco, USA
5. NIHR-Wellcome Trust Clinical Research Facility, King's College London, UK