Ventriculomegaly associated with multiple echo-dense nodules is characteristic of severe fetal toxoplasmosis and carries a poor prognosis. When the ventricles have normal size or are only mildly dilated, the nodules restricted to the parenchyma development may be normal.

Infection during pregnancy is common and the developing fetal brain is vulnerable to vertical transmission due to immaturity of the fetal immune system. Infection is a major cause of multiple organ abnormalities, including the neuraxis, due to the neurotropism of the infectious agents. This review sets out to give an overview of fetal infection, review the general principles of the nature and timing of the infectious insult with respect to outcomes, review the neuroimaging of infection by ultrasound and magnetic resonance imaging (MRI), and review the various pathogens involved, including the two most common, cytomegalovirus (CMV) and Toxoplasma, and also other common viral and nonviral infections.