2 | MATERIALS AND METHODS
This retrospective study analysed two-dimensional ultrasound, colour
Doppler and STIC images of CAT diagnosed using prenatal ultrasound at
the Gansu Maternal and Child Health Hospital from June 2017 to June
2022. The age of the pregnant women was 17–37 years (average 27.34 ±
4.76 years) and the first detected gestational week was 13–37 weeks
(average 23.92 ± 3.38 weeks). The exclusion criteria were incomplete
ultrasound or clinical data and lost to follow-up.
The Voluson E8, E10 colour Doppler ultrasound diagnostic instrument
(General Electric Co., Boston, MA, USA) and an abdominal volume probe at
a frequency of 2.0–5.0 MHz were used for the ultrasound. Pregnant women
were placed in the supine position, the main structures of the foetuses
were examined, and related growth and development assessments were
performed. Visceral locations were determined, beginning with the
transverse section of the abdomen. The foetal heart mode was selected,
and reserved sections were checked according to cardiac standards,
including two-dimensional ultrasonography, colour Doppler and STIC
volume images. The ventricular outflow tract section and the
three-vessel tracheal section were mainly observed. A CAT was considered
if the ventricular outflow tract view showed only one set of semilunar
valves, only one thick arterial trunk emerged from the left or right
ventricles, the normal order of the great arteries disappeared on the
three-vessel tracheal view, or only a single arterial trunk and the
superior vena cava were displayed. The woman was instructed to hold her
breath, and the STIC condition was selected for volume data acquisition
when the foetus was in a quiet state, and the connection between the
left and right pulmonary arteries and the common arterial trunk was
determined on the stereoscopic STIC images. The diagnosis was confirmed
by two deputy chief physicians with prenatal diagnosis qualifications.
The pregnancy outcomes were followed up in all cases.
The common arterial trunk was divided into 4 types using the Van Praagh
classification based on the origin of the pulmonary
artery:4 A1 type: the common pulmonary artery
originated from the left wall of the PTA (Figures 1a, 1b); A2 type: the
left and right pulmonary arteries originated from the posterior or both
lateral walls of the PTA, respectively (Figures 2a, 2b); A3 type:
pulmonary artery originated from a single trunk and the ductus
arteriosus, or collaterals supplied the other lung (Figures 3a, 3b);
type A4: persistent trunk with severed interrupted aortic arch (IAA).
SPSS 25.0 statistical software (SPSS Inc., Chicago, IL, USA) was used to
analyse the data. Maternal age and the detected gestational age were
normally distributed and expressed as mean ± standard deviation. The
count data are expressed as frequencies and percentages, and the
chi-square or Fisher’s exact test was used to compare the groups. All
results are two-tailed, and P <0.05 was considered
significant.