VP20.04: The fetal umbilical‐portal system in persistent right umbilical vein

The aim of this study was to describe the anatomy of the fetal umbilical-portal venous system, in fetuses with persistent right umbilical vein (PRUV). A prospective observational study was carried out at our tertiary referral ultrasound unit. All patients carrying a fetus diagnosed with PRUV underwent a comprehensive anatomy scan in addition to a detailed umbilical-portal system evaluation. Over a period of 18 months, 12 cases of PRUV were diagnosed and recruited. A unique anatomical venous pattern was recognised in all cases, appearing as a mirror image of the ordinary left umbilical-portal system (figure 1). As the right umbilical vein enters the liver, it drains into the portal sinus (PS) (the future to be right portal vein (RPV)). Three branches emerge from the PS/RPV resembling the configuration of the ordinary left portal vein (LPV). The inferior (RPVi) and superior (RPVs) branches course to the right side, while the medial (RPVm) course to the left. Then the PS/RPV courses to the left, at which point it merges with the main portal vein (MPV) to form the left portal vein (LPV), which give rise to the ductus venosus and then bifurcates to the anterior (LPVa) and posterior (LPVp) left branches, resembling the configuration of the ordinary right portal vein (RPV). PRUV has a unique umbilical-portal venous configuration mirroring that of the ordinary fetal portal system. Knowledge of the unique anatomy of this vascular anomaly can aid in cases where the portal venous anatomy is unclear and PRUV diagnosis is in doubt. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.