Neuroimaging in Secondary Headache Disorders.

A secondary headache may develop de novo or in patients with a history of primary headaches, and a thorough history and neurological exam often helps to suspect a secondary etiology. The causes of secondary headaches include tumors, vascular etiologies, structural brain disorders, infection, inflammation, and alterations of cerebrospinal fluid pressure dynamics. Computed tomography (CT) is very sensitive for detecting acute hemorrhage but magnetic resonance imaging (MRI) is preferred over a head CT in subacute and non-emergent cases. Obtaining the correct diagnosis may include incorporation of intravenous contrast agents, special imaging sequences, and functional imaging techniques.