The assessment of normal fetal brain volume by 3-D ultrasound.

The assessment of the fetal brain volume (BV) is very important in the evaluation of fetal growth. The purpose of this study is to use the three-dimensional (3-D) ultrasound (US) in constructing reference centiles of the fetal BV during normal gestation for clinical application. This study was undertaken by a prospective and cross-sectional design. In total, 203 singleton fetuses ranged between 20 and 40 weeks of gestation and fit the criteria of normal pregnancies were enrolled in this study. Our results showed that fetal BV is highly correlated with the gestational age (GA). Furthermore, using GA as the independent variable and the fetal BV as the dependent variable, the best-fit regression equation was BV (mL)=-171.48036+4.8079xGA+0.29521xGA2 (r=0.99, n=203, p<0.0001), with SD of BV (mL)=1.2533x(9.9474+0.07133xGA). In addition, the common growth parameters of the fetal biometry, such as biparietal diameter (BPD), occipitofrontal diameter (OFD), head circumference (HC), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW), were all highly correlated with the fetal BV (all p<0.0001). In conclusion, our data on the fetal BV assessed by 3-D US may serve as a useful reference in evaluating fetal growth.