Assessment of the third-trimester fetus using 3-dimensional volumes: a pilot study.
OBJECTIVE
To examine whether the third-trimester fetus can be assessed sonographically using 3-dimensional (3D) volume data sets.


METHODS
Twenty-seven consecutive third-trimester fetuses were evaluated. Fetuses were scanned using 2-dimensional (2D) imaging followed by 5 3D volume acquisitions. The initial scan was interpreted and reported based on the 2D images. The 3D volume data sets were independently reviewed offline several weeks later by 2 sonologists. Parameters evaluated included fetal presentation, placental location, amniotic fluid volume, fetal biometry including a calculation of estimated fetal weight, and major fetal anatomic structures. The result of the interpretation via 3D reconstruction of the volume from each of the 2 sonologists was compared with the original 2D sonography report.


RESULTS
Fetal presentation, amniotic fluid volume, and placental location with respect to the cervix were correctly identified 100% of the time by each sonologist. The estimated fetal weight was within 10% of the 2D estimate 89% (95% CI, 0.71-0.98) of the time for sonologist A and 96% (95% CI, 0.81-0.99) of the time for sonologist B. The majority of major anatomic landmarks were adequately seen by both sonologists.


CONCLUSIONS
Offline review of 3D volume data sets is a reliable method for determining fetal presentation, amniotic fluid volume, placental location, and estimating fetal weight in the third trimester.
Bromley
Bryann
B
Department of Radiology and Obstetrics & Gynecology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA.
Shipp
Thomas D
TD
Benacerraf
Beryl
B
D000653:Amniotic Fluid / Q000000981:diagnostic imaging*; D005260:Female; D005333:Fetus / Q000033:anatomy & histology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D015588:Observer Variation; D010920:Placenta / Q000000981:diagnostic imaging; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D016216:Ultrasonography, Prenatal / Q000379:methods*