Neuroimaging of infections of the central nervous system.

Neuroimaging plays a crucial role in the diagnosis and therapeutic management of neurologic infections. This article summarizes imaging findings in brain abscesses, ventriculitis, viral diseases, and opportunistic infections. In cases of uncomplicated meningitis, cranial computed tomography is sufficient to exclude brain edema, hydrocephalus, and skull base pathology. Magnetic resonance imaging (MRI) is superior in depicting complications (e.g., empyema, vasculitis). Diffusion-weighted imaging (DWI) shows parenchymal complications of meningitis earlier and is of help in differentiation of pyogenic abscess from other ring-enhancing lesions. Proton magnetic resonance spectroscopy can produce specific peak-patterns in cases of abscess, such as the presence of lactate and cytosolic amino acids. In toxoplasmosis, DWI may help to differentiate from lymphoma, showing no restriction of water diffusion. In patients with viral encephalitis, DWI allows earlier lesion detection. MRI has revolutionized the rapid diagnosis of spinal abscess.