Obtaining first trimester two-dimensional (2D) anatomical views with the aid of three-dimensional (3D) ultrasound volumes
By Jayne Lander, University of Oxford
Objectives
To assess whether fetal anatomy can be examined using 2D image slices extracted from a 3D volume taken at this gestation.
Methods
This was a prospective observational study of women attending a routine first trimester ultrasound scan between November 2021 and April 2022. A routine 2D first trimester scan was performed, followed by a 3D volume of the entire fetus, starting in the sagittal plane. If successfully obtained, the 3D volume was uploaded to GE 4D view software. Each 3D volume was examined in multiplanar view to assess whether 2D images of diagnostic quality could be extracted for the axial head, facial profile, stomach, cord insertion, bladder, bilateral hands and feet, crown-rump length (CRL) and nuchal translucency (NT).
Results
In total, 81 participants were prospectively recruited. A successful 3D volume was obtained for 94% of participants. It was possible to diagnostically evaluate the following structures using only the 2D image slices obtained from the 3D volume: CRL (88%), NT (72%), head (93%), facial profile (80%), stomach (62%), cord insertion (86%), bladder (22%) bilateral hands (97%), bilateral feet (93%).
Conclusions
A single 3D volume has the potential to provide information on key anatomical structures within minutes. With appropriate training, extraction of 2D images from this volume at 11-14 weeks allows evaluation of major anatomical structures in the first trimester, reducing time pressures on ultrasound departments, and may provide additional benefit in reducing the rate of repetitive strain injuries for sonographers. Future studies should aim at optimising 3D acquisition, taking into account more difficult to extract anatomies; and examine whether this could be a useful alternative to 2D imaging rather than an adjunct.