Fetal magnetic resonance imaging of the central nervous system: a pictorial essay.

Prenatal ultrasonography is the primary screening modality for the evaluation of fetal pathology. Ultrafast fetal MRI is a recent development that examines the fetus in utero. The short acquisition times (as short as 400 ms/slice) allow to picture freeze the fetus without the need for fetal sedation. The high spatial resolution, good contrast-to-noise ratio, and the multiplanar capabilities are especially advantageous in pathologies of the fetal central nervous system (CNS). Fetal MRI currently serves as a second-line imaging tool for complex fetal cerebral malformations and pathologies. Fetal ventriculomegaly, lesions within the posterior fossa, and abnormalities in cerebral myelination, migration, and sulcation are particularly well identified.