Surface vascular placental mapping with virtual endoscopy (sonofetoscopy): qualitative comparison of singleton and monochorionic twin pregnancies

Objective There are limited data on the antenatal ultrasound (US) assessment of the placental vascularity. In this study, we sought to evaluate the feasibility of the antenatal assessment of the placental vascularity using three-dimensional (3D) US with Doppler and to qualitatively characterise its features. Design Nonconsecutive series of singleton and monochorionic (MC) twin pregnancies with anterior placenta referred to a single Fetal Medicine Unit. Methods B-mode transabdominal US using multifrequency volumetric (4–8 MHz) transducers was performed, and power Doppler was applied to map the intraplacental vascularisation. 3D colour volumes were obtained from a section comprising the largest diameter of the placenta and processed using rendering technologies with flow. Results Overall, 3 singleton and 3 MC diamniotic twin pregnancies, of whom one was treated with laser fetoscopy due to twin-to-twin transfusion syndrome and one complicated by selective fetal growth restriction (sIUGR), were included. The median gestational age at examination was 21+6 (16+0–27+6). In all cases, 3D US with flow allowed clear visualisation of the cord insertion and the main vascular branches on the fetal surface of the placenta. In MC twins, the vascular anastomoses as well as the unequal vascular supply in the case of sIUGR could be demonstrated with 3D US with flow. Conclusion Antenatal evaluation of the surface placental vascularity using 3D US with Doppler is feasible. This technique, if prospectively tested, may be of value for planning in complicated MC twin pregnancies requiring fetoscopic treatment.