Delayed fenestration of Blake's pouch with or without vermian hypoplasia: fetal MRI at 3 tesla versus 1.5 tesla.

This pictorial case vignette supports the suggestion that mid-gestational MRI at 3 Tesla has the potential to exclude pronounced vermian hypoplasia with higher confidence than at 1.5 Tesla. However, the discrimination of mild hypoplasia from slight deformation of the cerebellar vermis will likely remain challenging.