In-utero evaluation of the fetal umbilical-portal venous system among fetuses with persistent right umbilical vein: Two-and three-dimensional ultrasonographic study

Objective: The aim of this study was to describe the anatomy of the portal system in fetuses with persistent right umbilical vein (PRUV).

Methods: Prospective observational study of fetuses diagnosed with PRUV. All patients underwent a comprehensive portal system anatomy scan supplemented by two-dimensional (2D) and three-dimensional (3D) color doppler modalities.

Results: 29 fetuses with PRUV were studied. We perceived an identical anatomical pattern in 28 fetuses. The right umbilical vein drains to the portal sinus (future right portal vein, RPV), which has a configuration of a left portal vein (LPV) in the normal left portal system, with three emerging branches: inferior (RPVi), medial (RPVm) and superior (RPVs). The RPV then courses to the left, towards the stomach to the point of the bifurcation of the main portal vein (MPV) to become the left portal vein. The LPV has an RPV configuration in a normal portal system with anterior (LPVa) and posterior (RPVp) branches. This anatomical layout mimics a mirror image of the normal anatomy of left portal system.

Conclusion: PRUV has unique umbilical portal venous anatomy, which is a mirror image of the normal left portal system. It can be demonstrated prenatally and serve as an additional tool for prenatal diagnosis of PRUV.