Quantitative assessment of placental vasculature and placental volume in normal pregnancies with the use of 3D Power Doppler.

PURPOSE: The aim of the study was to determine reference values for placental vascular indices and placental volume according to gestational age.

MATERIAL/METHODS: The assessment of placental vascular indices and placental volume using 3D Power Doppler and the Virtual Organ Computer-aided Analysis (VOCAL) technique was performed on 100 normal fetuses between 22 and 41 weeks of gestation. In this study the method of the individual setting of the power Doppler gain value was used. Only patients with entirely visualized placenta were included in the study.

RESULTS: No statistically relevant difference in the values of placental vascular indices and placental volume between different localizations of the placenta was detected. No statistically significant changes to placental vascular indices depending on gestational age were found. It enabled to determine the 10th, 50th and 90th percentile values for the vascularization index (VI), flow index (FI), vascularization-flow index (VFI), which are independent of gestational age. No correlation was found between placental volume and placental vascular indices.

CONCLUSIONS: The values of placental vascular indices are constant between the 22nd and 41st week of a normal pregnancy. Placental volume measured with the use of the VOCAL program increases between 22nd and 41st week of a normal pregnancy. In a normal pregnancy the placental vasculature increases adequately to the increase of its volume. The method of the individual setting of the power Doppler gain value makes it possible to achieve comparable values of placental vascular indices regardless of the distance between the probe and the placenta.