Figures
Fig. 1: Four-chamber views of different fetal
conditions. Panel a shows normal fetal anatomy, whereas panels b to f
depict cardiac anomalies, which will be discussed and further delineated
within the paper.
Fig. 2: Ebstein’s anomaly at 32 completed weeks with
STIC volume reconstruction and automatic labeling using FINE method. All
nine diagnostic planes are clearly depicted. The 3-vessel-trachea view
shows a size discrepancy of the great vessels with a small transverse
aorta. The 4-chamber view is abnormal with a marked left rotation (63
degrees) and ventricular asymmetry (LV<RV) and demonstrates
apically displaced tricuspid valve hinges (atrialization of the RV; aRV)
with somewhat thickened septal and lateral leaflets. In both the
5-chamber view (5CV) and left ventricular outflow tract (LVOT) views,
there is a small ascending aorta corresponding to tubular aortic
stenosis. The RVOT view shows normal main and right branch pulmonary
arteries and aRV. There is no regularly filled stomach in the abdominal
plane. The ductal arch view depicts the rotated tricuspid valve and
gives an impression of the remaining genuine RV. In contrast, the aortic
arch is rather hypoplastic, which confirms the finding of an obstructed
LVOT. In addition, an enlarged RA can be seen. The vena cave view
denotes similar findings.
A - transverse aortic arch; Ao - aorta; Desc - descending; IVC -
inferior vena cava; LA - left atrium; LV - left ventricle; P - pulmonary
artery; PA - pulmonary artery; RA - right atrium; RV - right ventricle;
RVOT - right ventricular outflow tract; S - superior vena cava; SVC -
superior vena cava; Trans - transverse.
Fig. 3: Tricuspid atresia at 22 gestational weeks. FINE
application on STIC volumes in both cases showed hypoplastic right-sided
cardiac structures. While assessing the altered anatomy in detail,
subtle but functional important differences can be noted. Whereas the
3VT view in the left panel (a) demonstrates an only slightly smaller
main pulmonary artery, there is a hardly a visible pulmonary arm in
panel b, corresponding to a severely hypoplastic or atretic RV outflow.
The RV in panel b is small and hypocontractile due to an obstructed
inflow via the atretic TV. The findings are referred to as hypoplastic
right heart (in contrast to the typical findings of tricuspid atresia
shown in panel a). A perimembranous VSD was seen in the 4CV, 5CV and
LVOT views (panel a); this interventricular communication could only be
assumed in the 4CV view (panel b). There was a normal interatrial
communication via a patent foramen ovale. The ductal arch view in panels
a and b is abnormally thin. The LVOT as well as the aortic arch in both
cases are normal.
Fig. 4: Severe pulmonary stenosis seen at 29 weeks.
Diagnostic plane reconstruction using FINE shows moderate cardiomegaly
and a slight left-rotated cardiac axis. The main pulmonary artery
depicted in the 3VT view is narrow due to a thickened pulmonary valve
(PV). There is a moderate asymmetry in ventricular and atrial size, and
the tricuspid valve leaflets appear to be thickened (related to marked
regurgitation confirmed by additional Doppler interrogation). The RV
cavity is narrow but shows myocardial hypertrophy. The LVOT is otherwise
normal; on the other hand, the RVOT shows an hourglass-like appearance
with an echoic, thickened PV corresponding to valvular stenosis. Both
arch views as well as the bicaval plane are normal.
Fig. 5: Fetus with critical pulmonary stenosis and an
intact ventricular septum at 33 weeks (panel a) and complex cardiac
anomaly with pulmonary atresia and an intact ventricular septum,
tricuspid atresia, LVOTO and pericardial effusion at 17 weeks (panel b).
In both cases, there is a marked cardiomegaly in late and early
pregnancy caused by a significant RVOT obstruction. The characterizing
anatomic sequelae of RVOTO are clearly depicted after reconstruction
using FINE. The 3VT view in both cases is abnormal. In panel a, both
vessels are equal in size, and the PV is thickened and domed through
cardiac cycle. In panel b, the pulmonary artery cannot be visualized,
resulting in an ‘I’-shaped appearance on the 3VT view. The entire
cardiac morphology is distorted, and the cardiac axis is left-rotated.
In panel a, the massively enlarged heart occupies more than half of the
thorax (merely due to the dilated RA) and extends from wall to wall. The
RV is round, and the myocardium shows marked hypertrophy. The TV
leaflets appear dysplastic and thickened (Doppler ultrasound revealed
regurgitation of >2 m/s). In panel b, the TV is atretic,
the LV is normal, and the MV is patent. The RVOT plane confirms the
narrow pulmonary trunk that bifurcates into the pulmonary arteries
(panel a), and no detectable pulmonary artery is visible in panel b. The
ductal arch in both cases is narrow or hypoplastic. The bicaval plane
shows the enlargement of the RA and normal venoatrial arrangement.
Fig. 6: Antenatal cases with different types of DORV
(a-d). 3D-reconstructed planes showing the complexity of malposition of
both great arteries. In all cases, the 3VT view shows an abnormal
parallel course of both outlet vessels arising from the anatomical RV.
The spatial arrangement of the aorta is right anterior in panel a (TGA
type at 20 gestational weeks), and it is considerably smaller than the
main pulmonary artery. This size discrepancy is confirmed in the LVOT
and aortic arch cut section views. There is a huge VSD displayed in the
5CV and LVOT views (noncommitted). The 4CV view further shows a common
atrium and atretic mitral valve but normal cardiac axis. The latter also
applies to the cardiac specimens in panel b and c (compared to a marked
left rotation in panel d). Panels b-d show both vessels located in a
side-by-side position, representing the most common anatomic variant of
DORV. According to the accompanying VSD, panels b and d show a doubly
committed arrangement of both outlet vessels. Note the extremely small
LV with an atretic MV and the diminished size of the main pulmonary
artery (3VT, RVOT) in panel d (seen in the 4CV, 5CV, and LVOT views).
Fig. 7: Tetralogy of Fallot at 22 weeks of gestation.
The 3VT view shows both vessels nearly equal in size with a patent DA,
and the 4CV view appears to be normal (the cardiac axis is slightly
left-rotated). There is a perimembraneous VSD with an overriding
medially shifted ascending aorta seen in the 5CV and LVOT views. The
RVOT and ductal arch views basically show the main pulmonary artery to
be smaller than expected.
Fig. 8: Fetus with ToFAPVS at 29 gestational weeks. The
complex cardiac anomaly can be depicted in its entirety in 8 of 9
diagnostic planes. Nonrestrictive interventricular communication in the
membranous septum. The 3VT view is distorted with no arterial duct. The
cardiac proportions are altered, and the cardiac axis is left rotated,
as seen in the 4CV, 5CV and LVOT views. There is an overriding aorta
with a broad aortic root, and, most strikingly, both the LVOT and RVOT
planes show a marked bulging of the main and branch pulmonary arteries
and a tiny hourglass-like narrowing at the level of the absent pulmonary
valve. The ductal arch cannot be properly reconstructed due the absent
DA. The aortic arch and the bicaval plane are otherwise normal.