Trigeminal Autonomic Cephalalgias -TACs-: a review of neuroimaging studies

Trigeminal autonomic cephalalgias are a group of disabling and excruciating primary headache disorders, consisting of cluster headaches, paroxysmal hemicrania, and short-lasting unilateral neuralgiform headaches with conjunctival injection and tearing (SUNCT). The attacks are strictly unilateral, presenting predominantly in the orbital, peri-orbital, and temporal regions, although pain may radiate to teeth and jaws. Pain is typically accompanied by prominent ipsilateral cranial autonomic symptoms. Ppathophysiology of these disorders is unknown and has therefore driven a number of studies using a variety of neuroimaging modalities in an attempt to unravel this. In this paper, we review the literature for neuroimaging studies that have been performed in these headache disorders and present their findings.