An assessment of vascularity and flow intensity of the placenta in normal pregnancy and pre-eclampsia using three-dimensional ultrasound.

OBJECTIVE To test the hypothesis that parameters of vascularity and flow intensity of the placenta as determined by three-dimensional (3D) ultrasound, (1) are different in normal pregnancy compared to pre-eclampsia (2) decrease from the basal plate towards the chorionic plate. METHODS Twenty women with normal pregnancy and 17 women with pre-eclampisa were studied. 3D power Doppler ultrasound was used to acquire individual placental volumes. Rotational measurements of placental volumes were acquired using virtual organ computer aided analysis (VOCAL). The power Doppler signals were then semi-quantified within 'histogram facility', which generates three vascularity and flow intensity parameters: flow index (FI), vascular index (VI) and vascularisation flow index (VFI). RESULTS FI, VI and VFI were lower in pre-eclampsia compared to normal pregnancy in all regions of the placenta. This difference was statistically significant in most regions of the placenta after accounting for gestational age, body mass index and placental site. We were not able to demonstrate a decreasing gradient of these parameters from basal plate to chorionic plate. CONCLUSION 3D ultrasound to assess placental vascularity and flow intensity appears to be an interesting research tool. However, other indices derived from Power Doppler may be more relevant to obstetric practice.