Imaging in headache disorders.

Patients with a suspected change in intracranial pressure or a trigeminal autonomic cephalgia require MRI. The need for investigation for other headache disorders is guided by the clinical evaluation of the patient. Particular care should be taken to identify any 'red flags'. Incidental findings on MRI occur in approximately 2% of patients. Patients with migraine have an increased rate of white matter lesions, but these are of uncertain clinical significance.