Is the "I-Sign" in the 3-Vessel and Trachea View a Valid Tool for Prenatal Diagnosis of D-Transposition of the Great Arteries?

Prenatal diagnosis of D-transposition of the great arteries remains less frequent compared to other major congenital heart defects. In this study, we examined how often the 3-vessel and trachea view was abnormal in a large series of prenatally diagnosed cases of D-transposition of the great arteries. We found that an abnormal 3-vessel and trachea view in the shape of an "I" ("I-sign"), which represents an anteriorly displaced aorta, was present in all fetuses with D-transposition of the great arteries when a 3-vessel and trachea view was successfully obtained. Therefore we believe that the 3-vessel and trachea view can be used to reliably detect D-transposition of the great arteries during prenatal sonography.