Volumetry during the first trimester of the pregnancy using three-dimensional ultrasonography

Classic human embryology was established by Wilhelm His in 1880-85. His
realized the need for magnified three-dimensional (3D) imaging and the need for
a model of the fetal anatomy.
Nowadays ultrasonography has a very important role in practical embryology and
it can not be missed in practice anymore. The development of computer
technology has opened new possibilities for 3D reconstructions. The first
attempt at constructing 3D images of fetus from ultrasound recordings was made
in the early 1980s by Brinkley et al. The first volumetric evaluation using 3-D
ultrasonopgraphy(US) to predict fetal loss during the first trimester was
performed by Steiner et al in 1994. Since a few years very specific
ultrasonogrpaphic volumetry measurements have become possible. This technique
combines the possibilities of ultrasonography and x-ray computed tomography(CT)
and is similar to 3D CT and magnetic resonance imaging both in principle and in
terms of the method of image creation. Due to this technique it is possible to
provide more data about the development of the pregnancy.
Authors of numerous large and small studies report the benefits of adding 3D
ultrasonography to the already well-established 2D ultrasonography to improve
the accuracy of prenatal diagnosis. 3D US takes less time, is more authomated
and less operator-dependent as 2D US.
In vitro studies demonstrated that 3DUS is superior to 2DUS for volumetric
measuring of objects with irregular shapes. With its reproducibility in vivo
being recently proved.
The aim of this study is to gain the normality curve of the volume of the fetus
using transabdominal and transvaginal 3DUS at 11+0 to 13+6 weeks of gestation.
Volumetric calculation by rotation has become possible through the introduction
of the VOCAL imaging program, an extension of 3D View (GE Kretz, ZIpf, Autria).
By measuring the normality curve we suggest that we can prove the diagnose of
pregnancy related disorders more early in the pregnancy by using this 3DUS
technique and the volumetric measurements. These anomalies are now diagnosed
later. It could be congenital anomalies or pregnancy related complications.

Understanding the normal development of the early pregnancy and observing this
process ultrasonographically has allowed us to monitor effectively first
trimester pregnancy, and recognize early signs of abnormal outcome.
The CRL (Crown-Rump-Length) is seen as the most accurate method to determine
the gestational age and in some cases also the pregnancy outcome.
We suggest that 3D ultrasonogrpahic volumetric measurements during the first
trimester will have a important surplus value at preterm diagnosis of
congenital anomalies or pregnancy related disorders.
The primary objective of this study is to measure the volume of the fetus at
11-13 weeks of gestation and calculating the normal values with the secundairy
objective to diagnose pregnancy related complications earlier.
This volume is obtained using 3DUS in singleton pregnancies undergoing the
nuchal translucency (NT) measurement.
By calculating the normal curve we will make allowance for age and length of
the parents, ethnicity and intoxications. The found volumina will be combined
to the outcome of the pregnancy.

This is a prospective cohort study accomplished in the Máxima Medical Centre
Veldhoven, the Netherlands with a duration of 13 months.

Ultrasound is already used for over more than 30 years. Untill now no
unprofitable effects are reported in practice and extensive scientific research
for mother as fetus.
The cooperating patients will not get an different treatment as the not
cooperating patients. But the not-cooperative patients will not get a 3DUS
examination.
This ultrasonogrphic examination will take about 30 minutes. Because of the
supplementary 3DUS it can take a few minutes more.