Appropriate use of neuroimaging in headache

Headache may be caused by primary disorders, such as migraines, or secondary disorders, such as intracranial neoplasm or hemorrhage. Imaging plays an important role in differentiating between primary and secondary headache disorders. This article reviews the effectiveness of computed tomography (CT) and magnetic resonance imaging (MRI) in the evaluation of a patient with a headache. It also discusses the utility and cost-effectiveness of performing imaging studies in patients with a headache and a normal neurological exam. Emerging imaging techniques such as functional MRI, positron emission tomography (PET) scans, and voxel-based morphometry (VBM) are also discussed.