P04.02: Can single three‐dimensional ultrasound volume of the fetal head be used for measurement both of the facial angle and the nuchal translucency?

Abstract

To evaluate if a three-dimensional (3D) ultrasound volume stored for the assessment of the facial fronto-maxillary (FMF) angle can also be used for measurement of nuchal translucency (NT). To evaluate whether a single 3D ultrasound volume of the fetal head in the sagittal plane is a faster and reliable method for determining the FMF angle and NT compared with standard two-dimensional (2D) ultrasound. This was a prospective study, in which NT of 100 fetuses was measured using the standard 2D ultrasound by a single FMF certified examiner. Also 3D volumes of the fetal head sagittal orientation were acquired by the same sonographer at the time of visit and stored for further analysis. The FMF angle was measured on the 3D images at the time of screening, however NT was measured on the stored 3D volumes off-line. The ability to reconstruct mid-sagittal view and perform measurement of nuchal translucency in 3D volumes was assessed. Consequently, the measurements using a conventional 2D sagittal view and 3D reconstructed sagittal view were compared. The nuchal translucencies of 100 fetuses were measured using both 2D technique and 3D multiplanar reconstruction. It was possible to measure NT in more than 90% of the stored fetal head volumes. In the paired 2D and 3D ultrasound measurements, the difference in NT measurements was less than 5% in more than 90% of the cases. The small variations between 2D and 3D measurements of NT were mainly caused by a different flexion of the fetal neck or slight deviation of the mid-line on 2D images. There is strong correlation between the measurements of the NT in 2D scanning and those obtained from 3D multiplanar reconstruction. Both NT and FMF angle can be easily and accurately measured on a single 3D volume of the fetal head acquired in the sagittal plane. The 3D technique seems potentially useful in fetuses that are not in an optimal position for standard 2D nuchal translucency measurement. Future research will be needed to prove this.