Characteristics of vascular anastomoses in monochorionic twin 587 placentas with selective intrauterine growth restriction via 89 three-dimensional computed tomography angiography

Objective To determine the characteristics of the choriovascular anatomy, especially the potential role of arteriovenous perfusion imbalance in the pathogenesis of selective intrauterine growth restriction (sIUGR) using three-dimensional computed tomography angiography (3D-CTA). Method Computed tomography angiography of the placental choriovascular tree from 15 twins with sIUGR and 15 twins without sIUGR were analyzed, and inter-twin vascular anastomoses were compared between the placentas from these two groups. The parameters evaluated were the presence and measures of artery-to-artery anastomoses (AAA), vein-to-vein anastomoses (VVA) or artery-to-vein anastomoses (AVA). Results The frequency of AAA, VVA, and AVA did not differ significantly between sIUGR and without sIUGR-pairs. The area of the vein draining to the AVA in the larger twin's placenta was significantly greater in sIUGR compared to when no sIUGR was present. Based on the net cross-sectional area difference we speculate that in sIUGR there is net flow from the smaller to the larger twin. Conclusion We used 3D-CTA to display the vascular anastomoses in sIUGR twin pairs, demonstrating a difference in cross-sectional diameter of the vein draining to the AVA.