Fetal echocardiography using Spatiotemporal Image Correlation (STIC) for the detection of congenital heart malformations (CHD).

Congenital heart malformations represent the most common severe congenital
disease. Approximately 8 out of 1000 babies are born with congenital heart
malformations. 1 Nevertheless cardiac anomalies are the most commonly
overlooked lesions. Prenatal diagnosis of congenital heart malformations allows
planning and delivery of timely and appropriate neonatal care.
Real-time 2D ultrasound, the routinely-used tool for fetal echocardiography, is
a sophisticated diagnostic method but it remains limited. The technique is very
operator-dependent and is commonly time consuming. The addition of imaging the
right and left outflow tracts to fetal heart examination has increased the
detection of cardiac defects, but the detection rate of isolated congenital
heart malformations still remains low.
Spatio-temporal image correlation (STIC) is the latest approach to clinical
assessment of the fetal heart. STIC is an automated volume acquisition in which
the array inside the transducer housing performs a slow, single sweep,
recording one single three-dimensional volume dataset. Echocardiography using
new STIC technology may have the potential for making the echoscopic screening
for congenital heart malformations less operator-dependent and may increase the
prenatal detection rate for congenital heart defects.
No studies however have systematically investigated the feasibility and
capability of STIC technology to perform a full cardiac examination when
cardiac anomalies are suspected and compared this with convertional 2D
echocardiography. Another field that is not yet has been studied is the
reproducibility of an echocardiographic assessment using STIC technology.

1. To investigate whether examination of STIC volumes give an investigator more
information about the cardiac anomaly compared to 2D ultrasound.
2. To evaluate the reproducibility of fetal heart examinations of STIC volumes
by different investigators.

1. During and ultrasound investigation when cardiac anomalies are suspected,
multiple STIC volume datasets are acquired from fetuses with different CHD with
gestational age ranging from 11 to 40 weeks. Before acquisition of a STIC
volume a full 2D cross-sectional echocardiographic examination is preformed by
one experienced sonographer. During the 2D echocardiographic examination a
listed number of anatomical structures are scored on their visibility. The STIC
volumes are examined off-line and are also scored on their ability to display
the listed cardiac anatomic structures when present. For the ability to
visualize the cardiac structures percentages are calculated to compare the two
forms of fetal cardiac examination

2. From a digital database containing STIC volume datasets volumes of twenty
fetus are selected with congenital heart defects. For each fetus two volume
datasets of sufficient quality are selected for review by one investigator.
Then the volumes are randomly assigned for a blinded review to three
independent investigators. All of the investigators are experienced in fetal
echocardiography and all will receive a training in the use of the software
used to examine the volumes off-line. All investigators will diagnose the
present CHD or exclude the existence of CHD for all twenty fetus examined. The
results of all three investigators are compared to examine inter-investigator
reproducibility of cardiac diagnoses using STIC technology.

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