Prenatal diagnosis of fetal congenitally corrected transposition of the great arteries

Background: Fetal congenitally corrected transposition of the great arteries (ccTGA) is a rare cardiac anomaly and the diagnosis remains a challenge for many sonographers in routine screening programs. We describe a new method of diagnosis by four-dimensional (4D) echocardiography and spatiotemporal image correlation (STIC).

Methods: We reviewed retrospectively 11 cases of fetal ccTGA complicated with ventricular septal defect. The four-chamber view (4CV) and the cardiac outflow tract views were obtained by conventional two-dimensional (2D) echocardiography. Atrioventricular connections were observed in the 4CV and ventriculoarterial connections in the cardiac outflow tract views. 4D volume data sets were acquired at the 4CV level and then analyzed by STIC. All volume data sets were displayed using the multiplanar modality, which allows simultaneous display of images in three orthogonal planes. The correlation of the three planes was used to reveal the spatial relationship of the two great arteries. The diagnosis was confirmed by postnatal echocardiography or by autopsy.

Results: By 4D echocardiography and STIC, the origin, course and relationship of the two great arteries could be revealed by moving the reference dot in the three correlated orthogonal planes: in ccTGA, the aorta could be seen to arise from the right ventricle, anterior and to the left of the pulmonary artery, and its course was upward and parallel to the pulmonary artery.

Conclusions: 4D echocardiography and STIC technique can assist 2D echocardiography in the diagnosis of ccTGA by revealing the spatial relationship of the transposed great arteries, improving the understanding of the anomaly and facilitating the examination.