MRI and multiplanar 3D ultrasound compared in the prenatal assessment of enlarged posterior fossa.

Our aim was to compare the diagnostic capabilities of the multiplanar mode of 3D ultrasound (3D US) and MRI in the assessment of a fetal enlarged cisterna magna. Two fetuses showing an enlarged posterior fossa by conventional two-dimensional ultrasound at 24 and 29 weeks of pregnancy were assessed using both diagnostic methods. One fetus was found to have Dandy-Walker syndrome malformation. In the other, the syndrome was ruled out using both methods. Our results suggest that multiplanar 3D US is able to achieve similar results as does MRI when observing the fetal brain.