Spatio-Temporal Image Correlation; the key to fetal EchocaRdiography
Part II congenital heart malformations.

Congenital heart defects (CHD) are the most common congenital anatomic
maformations, affecting approximately 0,6-5% of live born children. In neonates
with congenital malformations, CHD cause 20% of neonatal deaths and up to 50%
of infant mortality and morbidity in the first year of life. Nevertheless,
cardiac anomalies are the most commonly overlooked lesions. Prenatal diagnosis
of congenital heart malformations is associated with improvement in neonatal
morbidity and mortality.

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.
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 threedimensional volume dataset. Echocardiography using
STIC technology may have the potential to make the echoscopic screening for
congenital heart malformations less operator-dependent and may increase the
prenatal detection rate of congenital heart defects.

No studies however have systematically investigated the feasibility and
capability of STIC to perform a full cardiac examination when cardiac anomalies
are suspected. Another field that is not yet has been studied is the
possibility of "tele-medicine" via internet.

1. To evaluate the clinical usefulness of STIC with post-process rendering
capability. Our goal is to investigate whether STIC gives more accurate
information about a suspected cardiac anomaly, compared to conventional 2D
ultracardiography.
2. To investigate whtether STIC allows "tele-medicine".

During the ultrasound investigation, when cardiac anomalies are suspected,
multiple STIC volume datasets are acquired from fetuses with a gestational age
ranging from 12 to 40 weeks. Before acquisition of a STIC volume, a full 2D
echocardiographic examination is performed by one experienced sonographer.
During the 2D echocardiographic examination a listed number of anatomical and
morphological structures are scored, based on their visibility. The STIC
volumes are examined off-line, using the same check list. The scores from both
tests are calculated and compared. Eventually, the postmortem/postnatal
diagnosis acts as the gold standard.

The STIC volumes will be scored by three different experts at a remote site,
with a lot of experience in fetal echocardiography. All the differents experts
will make a diagnosis, based on the STIC volumes. The results will be compared.
Thereby, the possibility of "tele-medicine" in the future will be investigated.

Spatio-Temporal Image Correlation (STIC)

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