title: Chronic daily headache: authors' response.
authors.forename: Graeme C
authors.initials: GC
authors.lastname: Simpson
authors.forename: Celestine
authors.initials: C
authors.lastname: Santosh
mesh_terms: D020773:Headache Disorders / Q000000981:diagnostic imaging* / Q000209:etiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D014057:Tomography, X-Ray Computed