What has functional neuroimaging done for primary headache … and for the clinical neurologist?

Our understanding of mechanisms involved in primary headache syndromes has been substantially advanced using functional neuroimaging. The data have helped establish the now-prevailing view of primary headache syndromes, such as migraine and cluster headache, as brain disorders with neurovascular manifestations, not as disorders of blood vessels. This review focuses on the results of studies applying positron emission tomography, functional MRI, and voxel-based morphometry, and attempts to synthesize the growing body of literature to provide pathophysiological concepts. We will further outline future research directions and the clinical applicability of functional imaging in headache patients.