Quantitative analysis of normal fetal brain volume and flow by three-dimensional power Doppler ultrasound.

BACKGROUND Assessment of the fetal brain volume and blood flow is important in the evaluation of fetal growth. We used three-dimensional (3D) ultrasound and power Doppler to assess the fetal brain volume and the blood flow index during normal gestation. The relationships of these parameters were further analyzed. METHODS We assessed the total volume and the blood flow index of the fetal brain in normal pregnancies using 3D ultrasound (Voluson 730). The bilateral parietal diameter (BPD) plane was measured by a 3D transabdominal probe to scan the fetal brain under the power Doppler mode. Then, we quantitatively assessed the total volume of the fetal brain, mean grey area (MG), vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) by applying Kretz VOCAL software. RESULTS The study included 126 fetuses, ranging from 15 to 38 weeks of gestation. The total volume of the fetal brain was highly positively correlated with the gestational age (GA) (correlation coefficient [r] = 0.976, p < 0.0001). The MG, VI, and VFI were negatively correlated with the GA (correlation coefficient [r] = -0.520, p < 0.0001; [r] = -0.421, p < 0.001; [r] = -0.319, p < 0.0001). The FI was positively correlated with the GA (correlation coefficient [r] = 0.483, p < 0.0001). CONCLUSION 3D ultrasound can be used to assess the fetal brain volume and blood flow development quantitatively. Our study indicates that the fetal brain vascularization and blood flow correlates significantly with the advancement of GA. This information may serve as a reference point for further studies of the fetal brain volume and blood flow in abnormal conditions.