Fetal echocardiography using Spatiotemporal Image Correlation (STIC).
In vitro validation and examination of the fetal cardiac anatomy and function.

Congenital heart malformations represent the most common severe congenital
disease. The prevalence ranges from 4 to 8 cases per 1000 live births.(1)
Therefore the fetal heart is the subject of major screening programs aiming to
detect cardiac malformations in an early stage of pregnancy. Nevertheless,
cardiac anomalies are the most commonly overlooked lesions and many efforts
have been made to increase the detection rate of congenital heart
malformations. Another area that has received much attention is the evaluation
of cardiac function to evaluate fetal well being.
Spatio-temporal image correlation (STIC) is the latest ultrasonographic
approach to clinical assessment of the fetal heart. STIC is an automated volume
acquisition, recording one single three-dimensional volume dataset. The cardiac
volumes are then displayed as one real-time cardiac cycle, played in a
cine-loop. This loop can be played in slow motion or stopped at any time for
analysis and because there is a volume dataset, each of the scan planes can be
moved and rotated while maintaining the synchronized cardiac loop. These
possibilities give STIC technology the potential to increase detection rates
for congenital heart malformations.
Conventional ultrasound techniques together with techniques such as M-mode and
pulsed doppler have been used to estimate fetal cardiac function.
Two-dimensional and M-mode ultrasound- based studies have established a range
of cardiac dimensions in the normal and abnormal heart. For cardiac volume
calculations both 2D and M-mode ultrasound, however, have their limitations.
Because STIC technology gives the investigator the opportunity to freeze the
three-dimensional cardiac loop in end-diastolic and end-systolic phase, more
accurate volume measurements can be used to calculate fetal heart stroke
volume, cardiac output and ejection fraction based on 3D volume measurements.

We will investigate the feasibility of using STIC technology to evaluate the
fetal cardiac anatomy in different stages of gestation. Further we will
investigate the fetal cardiac function using STIC technology.

In this prospective longitudinal study STIC volume datasets will sequentially
be collected every four weeks from healthy fetuses with gestational age ranging
from 11 to 24 weeks.

STIC volumes will be scored on their ability to display different cardiac
structures used to evaluate cardiac anatomy. All displayed structures are
scored on a scale of 1 to 5, based on their visualization and image quality.

We will create normograms for stroke volume, ejection fraction and cardiac
output based on 3D volume measurements of right and left ventricular volume in
systole and diastole.

Also an in vitro validation of volume measurement using STIC will be preformed.

Ultrasound has been used in obstetrics since the 1970's. There are no proven
adverse effects of ultrasound investigations on foetus or mother.