The gap between the aorta and the superior vena cava: A sonographic sign of persistent left superior vena cava and associated abnormalities

Abstract

Objectives: To assess the distance between the right superior vena cava (SVC) and the aorta in fetuses with bilateral superior vena cava as a possible sonographic marker for this. Methods: This was a nested case-control study including 20 cases of bilateral SVC and 40 gestational age-matched controls. The distance between the right SVC and the aorta was measured at the level of the three-vessel trachea view in stored images, as well as the diameters of the aorta and the right SVC. Results: The distance between the aorta and the right SVC was significantly larger in the cases of a left SVC compared with controls, P <.001. A distance of 2.0 mm or more was found in 70% of the cases and 5% of th..