Purpose or Case Report: Central nervous system (CNS) infections acquired in-utero are a significant cause of fetal and neonatal morbidity and mortality. Early detection is crucial for timely therapy, prognostication, and peripartum planning. Fetal imaging plays an important role in diagnosing CNS infection and determining the extent of involvement. It has been of particular diagnostic importance with the current outbreak of Zika virus, a neurotropic virus that can result in severe CNS anomalies. An imaging review of commonly encountered congenital infections, including Zika virus, will be presented, with an emphasis on fetal magnetic resonance imaging (MRI).
Methods & Materials: A literature review was performed to determine the spectrum of fetal imaging findings that have been described in various congenital CNS infections. We demonstrate the range of neuroimaging findings of congenital CNS infection using a multi-institutional series of patients. The utility of ultrasound and MRI in prenatal imaging of CNS infections will be highlighted. Postnatal outcomes will be discussed.
Results: Congenital brain infections include the common TORCH infections (toxoplasmosis, rubella, cytomegalovirus, and herpes simplex). However, the range of possible infective pathogens is broad and also includes human immunodeficiency virus, parvovirus, varicella, Zika virus, among others – including bacterial agents. A wide spectrum of CNS abnormalities can occur depending upon the infectious agent, burden of disease and timing of infection with respect to gestational age. Many of which can be detected by fetal imaging, including hydrocephalus, microcephaly, calcifications, malformations of cortical development, and brain destruction. The timing and sensitivity of ultrasound and MRI modalities in the diagnosis and monitoring of fetal CNS infection has been shown to be important.
Conclusions: Fetal CNS infections can result in severe brain abnormalities. Knowledge of distinguishing prenatal imaging features of CNS infections is important for parental counseling and perinatal management. Recent advancements in fetal imaging, particularly fetal MRI, have made it possible to detect and define unique and common imaging findings of congenital CNS infections.