Maccabi Health Services, Ultrasound Unit, The Negev Medical Center, Beer Sheba, Israel.
Ultrasound Obstet Gynecol. 2009 Dec;34(6):634-42. doi: 10.1002/uog.7459.
To describe the normal anatomy of the fetal umbilical-portal venous system (UPVS) and to assess possible anatomical variants of the main portal vein (MPV) insertion into the portal sinus (PS).
This was a prospective cross-sectional study of low-risk patients between 14 and 36 weeks of gestation. Two- (2D) and three-dimensional (3D) ultrasound techniques combined with color and high-definition flow Doppler were used to evaluate the fetal UPVS. The standard transverse plane of the fetal upper abdomen, used for measuring the abdominal circumference, was taken in all cases as the point of reference. A longitudinal section was taken to identify the normal course of the umbilical vein and ductus venosus (DV). We performed offline analysis of all gray-scale and color Doppler 2D and 3D volume datasets.
Two hundred and eight fetuses were included in the study. The umbilical vein was observed to course in a cephalad direction from its entry point into the fetal abdomen, joining the L-shaped PS, a confluence of vessels that is the main segment of the left portal vein (LPV). Three branches emerge from the LPV: two to the left, the inferior and superior branches, and one to the right, the medial branch. The main LPV then courses abruptly to the right. Following the emergence of the DV, the communication of the MPV with the LPV marks the point at which the vessel becomes the right portal vein (RPV), giving rise to its anterior and posterior branches. We were able to define three main variants of connection between the MPV and the PS. In 140 (67.3%) fetuses the MPV was connected to the LPV in an end-to-side T-shaped anastomosis, in 26 (12.5%) fetuses the MPV connected with a side-to-side X-shaped anastomosis and in 30 (14.4%) fetuses the two vessels ran in parallel with a short communicating segment, in an H-shaped anastomosis. In the remaining 12 (5.7%) cases classification into one of these three groups was not possible due to intermediate morphology.
Knowing the normal anatomy of the UPVS and being aware of the possible variants of the connection between the MPV and the PS is a fundamental requirement for accurate prenatal diagnosis of the anomalies of the fetal UPVS.
描述胎儿脐门静脉系统（UPVS）的正常解剖结构，并评估主门静脉（MPV）插入门静脉窦（PS）的可能解剖变异。
这是一项针对 14 至 36 孕周低危患者的前瞻性横断面研究。二维（2D）和三维（3D）超声技术结合彩色和高清流量多普勒用于评估胎儿 UPVS。所有病例均采用测量腹围的胎儿上腹部标准横切面作为参考点。取纵向切面以确定脐静脉和静脉导管（DV）的正常走行。我们对所有灰阶和彩色多普勒 2D 和 3D 容积数据集进行离线分析。
本研究共纳入 208 例胎儿。脐静脉从其进入胎儿腹部的入口处呈向头侧方向走行，与 L 形 PS 汇合，PS 是左门静脉（LPV）的主要节段。LPV 有三个分支：两个向左分支，即下支和上支，一个向右分支，即内侧支。LPV 然后突然向右转。DV 出现后，MPV 与 LPV 的连通处标志着该血管成为右门静脉（RPV）的位置，形成其前后分支。我们能够定义 MPV 与 PS 之间的三种主要连接变异。在 140 例（67.3%）胎儿中，MPV 以端侧 T 形吻合方式与 LPV 相连，在 26 例（12.5%）胎儿中，MPV 以侧侧 X 形吻合方式相连，在 30 例（14.4%）胎儿中，两血管平行走行，有短的连通段，呈 H 形吻合。在其余 12 例（5.7%）病例中，由于中间形态，无法归入这三组中的任何一组。
了解 UPVS 的正常解剖结构，并了解 MPV 与 PS 之间连接的可能变异，是准确产前诊断胎儿 UPVS 异常的基本要求。
