Imaging of CNS Fungal Infections: Review Article

Abstract

Fungal infections of the central nervous system (CNS) are usually identified in immunocompromised patients but rare in immunocompetent hosts. The clinical and imaging manifestations are mainly influenced by types of fungal pathogen and immune status of the patients. The CNS fungal infections can develop through hematogenous dissemination from primary site of infection, cerebrospinal fluid seeding, or direct extension from adjacent sources of infection. Fungal infections can result in meningitis, meningoencephalitis, cerebritis, granuloma, or abscess formation, which imaging findings are often non-specific and difficult to distinguish from bacterial or tuberculous infection, non-infectious inflammatory disease, or even intracranial neoplasm. Vascular complications including vasculitis, cerebral infarction, or mycotic aneurysm are commonly present due to angioinvasion of fungal hyphae. In addition, some characteristic imaging features of fungal infections can be identified by computed tomography (CT) or magnetic resonance imaging (MRI), such as intracavitary projections in fungal abscesses and gelatinous pseudocysts in cryptococcosis that could help suggest the diagnosis. Recognizing the imaging findings of common intracranial fungal infections combined with appropriate clinical setting is crucial for allowing early diagnosis and leading to early specific treatment. The present article reviewed common imaging findings of CNS fungal infections and distinct imaging features of specific pathogens. Keywords: Fungal infection, Brain abscess, Cryptococcosis, Central nervous system (CNS), Computed tomography (CT), Diffusion weighted imaging (DWI), Magnetic resonance imaging (MRI)