Introduction
Both the double aortic arch (DAA) and the right aortic arch with the
mirror-image branches (RAA-MB) are considered as abnormal development of
the aortic arch. However, their prognoses are quite different.
Therefore, it is necessary to make a differential diagnosis of the DAA
and the RAA-MB in the fetus, which is helpful for the prenatal prognosis
consultation. Previous studies suggested that the three-vessel-trachea
view and their adjacent view could be used to distinguish
them.1 However, if there is hypoplasia or atresia in
the posterior part of the left aortic arch, its manifestations are very
similar to those of the RAA-MB, making it very difficult to distinguish
both. The 3D STIC technique increased the sensitivity of fetal
echocardiography for detecting arch anomalies.2 The
DAA forms an ”O” vascular ring, 1, 3 while the RAA-MB
itself does not.4 The main difference between the two
is to observe whether the first branch of the ascending aorta is
connected with the descending aorta. However, the right aortic arch is
usually higher than the left one, which cannot be displayed completely
in one view. Moreover, in the same view, the angle between the right
aorta and the first vessel branch can be shown. Therefore, we
hypothesized that there might be a difference among the angle between
the two arches of the DAA and that between RAA and the first branch of
the right arch. To our best knowledge, this is the first study to
elucidate on that difference. Based on two-dimensional color
echocardiography, the angles between the two aortic arches and the RAA
and its first branch were measured to distinguish them in this study.