Anatomic variations of the left portal vein and its branches in the fetal period

Objective: To define the non-pathological branches of the left portal vein and the anatomical variations of these branches in developmental anatomy, to determine the diameter of the left portal vein and the length of the portal sinus. Method: 735 single, uncomplicated pregnant women were included in the study. The L-shaped umbilical-portal venous system was placed in the transverse plane of the fetal abdomen in the images taken by advanced dynamic flow (ADF), which is a broadband color Doppler ultrasonography technique. Umbilical vein (UV), left portal vein (LPV), portal sinus (PS), ductus venosus (DV) and right portal vein (RPV) were imaged with grayscale and ADF and color comparison mode (mirror image) ultrasound technique. After a period of experience, the "capture and stretch" technique was used to visualize the main portal vein and RPV branches in color Doppler images. Patients with diabetes mellitus, transport or preeclampsia, poly/oligo-hydramnios, fetal congenital abnormality, ductus venosus agenesis, fetal growth protector and fetal size were excluded from the study. Results: The average length of the intrahepatic UV was found to be 17.69mm with a diameter of 4.84mm. Laterally from the left portal vein, two branches were found in 90% of cases, a single branch in 5.2% of cases, and three branches in 4.4% of cases. In 7.1% of cases, it originated as a single branch and then divided into two. The average length of the portal sinus was found to be 25.18mm. In the medial portion of the left portal vein, a single branch was observed in 74.7% of cases, two branches in 18% of cases, and three branches in 1.1% of cases. Conclusion: In our study, the measurements of the left portal vein, its branches, the UV, and the portal sinus, which have not been clearly defined in the literature, were identified. Key words: fetal left portal vein, fetal umbilical vein, obstetric color Doppler.