Fungal infections of the central nervous system.

Fungal infections of the central nervous system (CNS) frequently occur in the immunocompromised or debilitated host. Imaging findings are non-specific but may be organized into extra-axial, parenchymal, and vascular categories. Furthermore, knowledge of fungal morphology may predict the imaging manifestations with large, hyphal species having a predilection for brain parenchymal involvement, while small, unicellular organisms typically result in meningitis. Advanced imaging techniques such as diffusion-weighted imaging, MR perfusion and MR spectroscopy, when combined with clinical findings, may help in differentiating fungal disease from other mimckers such as pyogenic infection or cystic metastases.