Fetal MRI features related to the Chiari malformations.

Fetal magnetic resonance (MR) imaging may add to ultrasonography some valuable information in the assessment of Chiari malformations during their developmental stage. In Chiari type I, MR imaging role seems mainly related to research on pathophysiology issues rather than to real clinical applications. Some Chiari type II features may be better characterized in utero by MR imaging: such as the degree of downward displacement of cerebellum, possible abnormal signal changes within brain parenchyma and the type of meningocele (covered or uncovered).