Contrast enhancement in meningeal and extra-axial disease.

Intravenous contrast agents have become an indispensable tool in the CT and MR evaluation of the CNS. With regard to extra-axial and meningeal processes, many lesions would be missed were it not for their tendency to enhance. Unfortunately, contrast enhancement for every patient undergoing neuroimaging may not be cost-effective in the coming era of cost containment. Nonetheless, for patients with an underlying history of neoplastic or possible infectious disease and those whose symptoms are not explained by the noncontrast imaging findings, contrast-enhanced imaging should be performed.