Introduction
Introduced as a promising tool, volumetry of the fetal heart using
spatial-temporal image correlation (STIC) has been shown to enable
obtaining in-depth information retrieved from large volume data sets of
the fetal heart and proven to be of additional value in offline analysis
for multidisciplinary consultation, facilitating a more detailed
understanding of the complex fetal anatomy and reducing operator
dependency1,2. Multiplanar navigation and the
application of a number of imaging algorithms are of particular value in
evaluation of cardiovascular integrity or function (in combination with
color Doppler or M-mode). Nevertheless, quite a number of publications
have stated that these techniques have rather poor reliability in
clinical practice and have consequently faced limited use despite their
widespread availability for more than 15 years3. Thus,
the major disadvantages of STIC interrogation include the following:
professional experience has been shown to be the most limiting factor in
the image quality of acquired volumes, and orientation within the volume
is cumbersome and remains challenging for most operators, precluding its
use in a screening setting4. This illustrates the
urgent need for a concept to standardize 4D echocardiography and aid
targeted navigation in STIC volume data sets.
In 2013, fetal intelligent navigation echocardiography (FINE) emerged as
a novel semiautomatic technique to dissect fetal cardiac anatomy after a
STIC volume has been acquired. This intelligent navigation technology is
based on manual selection of key anatomical landmarks, allowing the
system to automatically realign the volume, reorientate and standardize
the anatomical position to find, extract, and display specific
diagnostic cardiac planes5. Recent studies have
demonstrated that the FINE method is able to successfully generate all
nine standard views for complete fetal echocardiography in 96–100 % of
2nd and 3rd trimester fetuses. It has also been shown that detection of
an altered cardiac morphology in case of congenital heart defects (CHDs)
is feasible with high sensitivity (98 %) and specificity (93
%)6.
In this two-part manuscript, we aimed to scrutinize the advantages of
workflow-based semiautomatic postprocessing of STIC volumes for detailed
prenatal assessment of cardiovascular anatomy in fetuses affected by
congenital heart disease (CHD). Despite the fact that from a
physiological perspective left and right ventricular performance are
strictly related to that of the other (ventricular interdependence), for
teaching purposes, we focused on predominantly right- and left-sided
anomalies separately. We highlight the educational value of standardized
reconstruction of both cross-sectional and longitudinal cardiac planes
in order to aid in establishing correct diagnoses in index cases of
normal and anomalous fetal hearts assessed during mid- and third
trimester targeted ultrasound.