Contrast enhancement in meningeal and extra-axial disease

Intravenous contrast is firmly established as an important tool in imaging of the central nervous system. Were it not for our ability to perform contrast-enhanced studies, many extra-axial and meningeal disease processes would go undetected, possibly with grave consequences. Other lesions are diagnosed more conclusively by their lack of enhancement. Whether or not a lesion is detected on noncontrast studies, the addition of a contrast agent is indicated in a variety of clinical circumstances. Patterns of diffuse meningeal enhancement are important to recognize despite frequent lack of specificity.