FETAL FACE VISUALIZATION USING 3-DIMENSIONAL ULTRASONOGRAPHY

Evaluation of the fetal face is an essential part of the sonographic e xamination for high risk pregnancies. Even under optimal conditions, t he complex curvature of the face makes it difficult to obtain adequate images with two-dimensional ultrasonography, and many cross-sectional images are required to obtain a complete impression. The purpose of t his paper is to show preliminary work in assessing the utility of thre e-dimensional ultrasonographic visualization of the fetal face. Fetal facial features were evaluated with three-dimensional sonography by sc anning with a volume transducer and compared to conventional two-dimen sional ultrasonographic images in 27 fetuses (gestational ages 10 to 3 9 weeks). Surface rendered three-dimensional sonographic images of the fetal face were obtained in 24 of 27 fetuses. In four cases the upper lip was clearly imaged on three-dimensional ultrsonography when it co uld not be seen on two dimensional ultrasonography. Information requir ing multiple planes with two-dimensional ultrasonography could be demo nstrated on a single image from three-dimensional ultrasonography. Ima ges of abnormal faces were seen with both two- and three-dimensional u ltrasonography in two cases of cleft lip and one case of holoprosencep haly. Volume data acquisition required approximately 10 sec and recons truction required approximately 5 see with instantaneous review of pla nes through the volume data set. Surface rendering required 2 to 10 mi n depending on the angular viewing range. Three-dimensional ultrasonog raphy has the potential to provide improved visualization of the fetal face compared with conventional two-dimensional sonographic imaging.