Three- and four-dimensional ultrasonography for the structural and functional evaluation of the fetal face.

Ultrasonographic examination of the fetal face can provide information that may lead to the diagnosis of anomalies in other organs or systems. Thus, the fetal face represents a "diagnostic window" for fetal diseases and syndromes. Three-dimensional ultrasonography (3DUS) improves the evaluation of anatomic fetal facial anomalies over what is possible by 2-dimensional ultrasonography (2DUS). Four-dimensional ultrasonography (4DUS), by adding the temporal component to the examination, allows visualization of facial expressions that might be useful in the study of fetal behavior and maternal-fetal bonding. In this article, we evaluate the potential of 3D/4DUS for the study of structural and functional development of the fetal face.