Prenatal diagnosis of transposition of great arteries - an update review.

The simple transposition of the great arteries (TGA) is a cyanotic heart disease that accounts for 5% to 7% of all congenital heart diseases (CHDs). It is one of the CHDs that is commonly underdiagnosed in utero, with prenatal detection rates of less than 50%. The simple TGA is characterized by ventriculoarterial discordance and atrioventricular concordance with the great arteries in a parallel relationship. The prenatal diagnosis of TGA influences the postnatal outcome, thus, requiring planned delivery and perinatal management. For these reasons, it is important to identify the ultrasound key markers of TGA to improve the prenatal diagnosis and consequently provide perinatal assistance. The presence of two vessels instead of three in the three-vessel tracheal view, the parallel course of the great arteries, and the identification of the origin of each of the great arteries are the key markers in diagnosing TGA. In addition to the classical ultrasound signs, other two-dimensional ultrasound markers such as an abnormal right convexity of the aorta, an "I-shaped" aorta and "boomerang sign" may also be used to diagnose TGA in the prenatal period. When disponible, an automatic approach using four-dimensional technologies such as spatio-temporal image correlation and sonographically based volume computer-aided analysis may improve the prenatal diagnosis of TGA. This study aimed to review the ultrasound markers that can be used in the antenatal diagnosis of TGA, with a focus on the tools used by sonographers, obstetric and fetal medicine team, and perinatal cardiologists to improve this diagnosis.