Early prenatal MR imaging diagnosis of polymicrogyria.

The case of a 24-week-old fetus that showed features suggestive of focal cortical developmental anomaly at prenatal MR imaging is presented. The anomaly was confirmed to be polymicrogyria by 34-week prenatal and the 3-day postnatal MR imaging studies. The report demonstrates that the development of polymicrogyria can be assessed throughout different stages by prenatal MR imaging. In the case reported, the additional presence of periventricular heterotopia strongly suggests that a neuronal migration alteration coexisted with a postmigrational disorder.