MRI of CNS fungal infections: review of aspergillosis to histoplasmosis and everything in between.

Fungal infections of the central nervous system (CNS) represent a wide spectrum of diseases with some common magnetic resonance imaging (MRI) features. Risk factors include immunocompromise of any cause and living in endemic areas. CNS infection occurs through hematogenous spread, cerebrospinal fluid seeding, or direct extension. MRI features include heterogeneous or ring reduced diffusion and weak ring enhancement. Angioinvasive aspergillosis is characterized by multifocal hemorrhagic lesions with reduced diffusion. Cryptococcosis results in gelatinous pseudocyst formation in the basal ganglia. Mucormycosis is characterized by frontal lobe lesions with markedly reduced diffusion. Candidiasis is usually manifest by numerous microabscesses of less than 3 mm occurring at the corticomedullary junction, basal ganglia, or cerebellum. Coccidioidomycosis often results in meningitis with contrast enhancement of the basal cisterns. Blastomycosis and histoplasmosis are rare infections with parenchymal abscesses or meningitis. Recognizing the imaging features of CNS infections allows for early, aggressive treatment of these otherwise rapidly fatal infections.