Prenatal assessment of normal fetal humerus volume by three-dimensional ultrasound.

Because fetal humerus dysplasia is associated with a variety of congenital syndromes, prenatal assessment of the fetal humerus growth is very important. The fetal humerus volume is one of the indexes in evaluating the humerus growth, but it has never been studied by 3-D ultrasound (US) in utero. To establish a normal reference chart of the fetal humerus volume for clinical use, we undertook a prospective and cross-sectional study using 3-D US to assess the fetal humerus volume in normal pregnancy. A total of 216 singleton fetuses that ranged between 20 and 40 weeks of gestation and fit the criteria of normal pregnancies were included in this study. Our results showed that the fetal humerus volume is highly correlated with the gestational age (GA). Using GA as the independent variable and the humerus volume as the dependent variable, the best-fit regression equation was humerus volume (mL) = 0.0044GA(2) - 0.0841GA + 0.6874 (r = 0.97, n = 216, p < 0.0001). For clinical use, a chart of normal growth centiles of the fetal humerus volume was then established based on this equation. In addition, the common indexes of fetal biometry, such as biparietal diameter, occipitofrontal diameter, head circumference, abdominal circumference, femur length and estimated fetal weight, were all highly correlated with the humerus volume (all p < 0.0001). In conclusion, our data of the fetal humerus volume assessed by 3-D US can serve as a useful reference in evaluating the fetal humerus growth during normal gestation.

Assessment of fetal adrenal gland volume using three-dimensional ultrasound.

To assess the normal fetal adrenal gland volume during normal gestation, we performed a prospective study on 119 normal fetuses with gestational age ranging from 21 to 40 weeks using a 3-D ultrasound (US) volume scanner with a pure cross-sectional design. Polynomial regression analysis was calculated to find the best-fit model between gestational age (GA) and adrenal gland volume. In addition, estimated fetal weight (EFW) was also measured to demonstrate the correlation between adrenal gland volume and fetal weight. Our results showed that fetal adrenal gland volume is highly correlated with GA. Furthermore, using GA as the independent variable and adrenal gland volume as the dependent variable, the best-fit regression equation was adrenal glands volume (mL) = -0.2683 x GA + 0.0082 x GA(2) + 3.1927 (r = 0.93, n = 119, p < 0.0001). For clinical use, a chart of normal growth centiles of fetal adrenal gland volume in utero was then calculated based on this equation. In addition, fetal adrenal gland volume during normal gestation is also highly correlated with EFW (p < 0.0001). In conclusion, our data of fetal adrenal gland volume assessed by 3-D US can serve as a useful reference in evaluating fetal growth status during gestation.

Assessment of normal fetal upper arm volume by three-dimensional ultrasound.

Fetal upper arm volume (UAV) is closely related to fetal growth and nutrition status. In the past, 2-D ultrasound (US) has shown limitations in assessing fetal UAV. With the recent advancement of 3-D US, the limitation in assessing fetal UAV by 2-D US can be overcome. To establish a reference chart of fetal UAV for clinical use, a prospective and cross-sectional study using 3-D US was undertaken to assess the fetal UAV in normal pregnancy. In total, 206 singleton fetuses ranging between 20 and 40 weeks of gestation that fit the criteria of normal pregnancies were enrolled in this study. Our results showed that fetal UAV is highly correlated with the gestational age. Furthermore, using gestational age (GA) as the independent variable and UAV as the dependent variable, the best-fit regression equation was UAV (mL) = 43.546 - 4.530 x GA + 0.133 x GA(2) (r = 0.913, n = 206, p < 0.0001). For further clinical use, a chart of normal growth centiles of fetal UAV in utero was then calculated based on this equation. In conclusion, we believe our data of fetal UAV assessed by 3-D US can serve as a useful reference in evaluating fetal growth and nutrition status during gestation.

Three-dimensional ultrasound in the assessment of normal fetal thigh volume.

Accurate assessment of the fetal organ volumes is very important in the evaluation of fetal well-being and maturation. Previous investigators have pointed out that fetal thigh volume (ThiV) may be a useful predictive factor of intrauterine growth retardation. Yet, 2-D ultrasound (US) is limited in assessing fetal ThiV accurately. With the recent advance of 3-D US, the limitation in assessing fetal ThiV by 2-D US can be overcome. To establish a normal reference chart of fetal ThiV for clinical use, a prospective and cross-sectional study using 3-D US was undertaken to assess the fetal ThiV in normal pregnancy. In total, 204 singleton fetuses ranging between 20 and 40 weeks of gestation and fitting the criteria of normal pregnancies were enrolled in this study. Our results showed that fetal ThiV is highly correlated with the gestational age (GA). Furthermore, using GA as the independent variable and ThiV as the dependent variable, the best-fit regression equation was ThiV (mL) = 35.494 - 4.985 x GA + 0.183 x GA(2) (r = 0.91, n = 204, p < 0.0001). For further clinical use, a chart of normal growth centiles of fetal ThiV was then calculated based on this equation. Furthermore, common indexes of 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 ThiV (all p < 0.0001). In conclusion, our data of fetal ThiV assessed by 3-D US can serve as a useful reference in evaluating fetal growth and nutrition status during normal gestation.

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.

The assessment of normal fetal liver volume by three-dimensional ultrasound.

Liver volume (LIVV) is very important in determining the status of fetal growth. However, to measure human fetal LIVV in utero precisely and noninvasively is not an easy task. With the recent advancement of three-dimensional (3-D) ultrasound (US), the limitation in assessing fetal LIVV by 2-D US can be overcome. The purpose of this study was to establish a normal reference chart of fetal LIVV for clinical use. A prospective and cross-sectional study using 3-D US was undertaken to assess the fetal LIVV in normal pregnancy. In total, 226 singleton fetuses ranging between 20 and 40 weeks of gestation and fitting the criteria of normal pregnancies were enrolled in this study. Our results showed that fetal LIVV is highly correlated with the gestational age (GA). Furthermore, using GA as the independent variable and fetal LIVV as the dependent variable, the best-fit regression equation was LIVV (mL) = -398.26 + 46.199 xGA - 1.7567 x GA(2) + 0.0236 x GA(3) (r = 0.97, n = 226, p < 0.0001), with SD of LIVV (mL) = 1.2533 x (0.77956 + 0.17267 x GA). These common indexes of fetal biometry, such as biparietal diameter (BPD), occipitofrontal diameter (OFD), head circumference (HCi), abdominal circumference (ACi), femur length (FL), and estimated fetal weight (EFW), were all highly correlated with fetal LIVV (all p < 0.0001). In conclusion, our data of fetal LIVV assessed by 3-D US can serve as a useful reference in evaluating fetal growth status during normal gestation.

Volumetric assessment of normal fetal lungs using three-dimensional ultrasound.

We attempted to construct normal reference centiles of fetal lung volume (LV) for clinical application by using three-dimensional (3-D) ultrasound (US) during normal gestation. A prospective study was performed on 195 healthy fetuses with gestational age (GA) ranging from 20 to 40 weeks for the assessment of fetal LV using a 3-D US volume scanner with a mixture of cross-sectional and serial measurements. Polynomial regression analysis was calculated to find the best-fit model between GA, right lung volume (RLV), left lung volume (LLV) and total lung volume (TLV). In addition, common fetal growth parameters, such as biparietal diameter (BPD), occipitofrontal diameter (OFD), head circumference (HCi), abdominal circumference (ACi), femur length (FL) and estimated fetal weight (EFW) were also measured to demonstrate the correlations between RLV, LLV, TLV and these parameters. Our results showed that RLV, LLV and TLV were highly correlated with GA. Using GA as the independent variable and RLV, LLV and TLV as the dependent variable, the best-fit regression equations were: RLV (mL) = 0.067 GA(2) - 1.2464 GA + 2.7825 (r = 0.95, n = 173, p < 0.0001), LLV (mL) = 0.0573 GA(2) - 1.599 GA + 12.454 (r = 0.95, n = 159, p < 0.0001) and TLV (mL) = 0.1263 GA(2) - 2.982 GA + 17.448 (r = 0.96, n = 152, p < 0.0001). For clinical use, a chart of normal growth centiles of fetal LV in utero was then calculated based on this equation. Furthermore, RLV, LLV and TLV were also highly correlated with the common fetal growth parameters during normal gestation (all p < 0.0001). In conclusion, the 3-D US nomograms of the fetal lung volume established in this study can be utilized as useful references in prenatal detection of fetal pulmonary pathologic status and relevant abnormalities.

Assessment of normal fetal liver blood flow using quantitative three-dimensional power Doppler ultrasound.

Fetal liver blood flow is very important for fetal hemodynamics. To assess the development of fetal liver vascularization and blood flow in normal gestation, we measured the fetal liver vascularization and blood flow in normal fetuses using the three-dimensional (3-D) power Doppler ultrasound (US) and quantitative 3-D power Doppler histogram analysis. This study was undertaken with a prospective, cross-sectional design. In total, 196 normal singletons with gestational age between 20 and 40 weeks were included. The 3-D power Doppler US and the quantitative histogram analysis were used to assess the fetal liver vascularization index (VI), flow index (FI), vascularization-flow index (VFI) and mean greyness in each case. Our results showed that all the fetal liver VI, FI and VFI increased significantly with gestational age (GA), whereas, fetal liver mean greyness decreased with GA. Using GA as the independent variable, the linear regression equations for fetal liver VI, FI, VFI and mean greyness were VI = 0.5746 x GA - 5.8264 (r = 0.86, p < 0.0001), FI = 0.3291 x GA + 35.624 (r = 0.35, p < 0.001), VFI = 0.2905 x GA - 3.4871 (r = 0.82, p < 0.0001) and mean greyness = -0.2034 x GA + 42.315 (r = -0.20, p < 0.0001). In addition, fetal liver VI, FI, VFI and nean greyness were all significantly correlated with common fetal growth indexes, such as biparietal diameter, occipitofrontal diameter, head circumference, abdominal circumference, femur length and estimated fetal weight. Our study indicates that normal fetal liver vascularization and blood flow change significantly with the advancement of GA as well as fetal growth indexes. We believe our data may serve as a reference for further studies of fetal liver blood flow in abnormal conditions.

Prenatal diagnosis of fetal multicystic dysplastic kidney with two-dimensional and three-dimensional ultrasound.

Fetal multicystic dysplastic kidney (MCDK) may have grave prognosis and prenatal diagnosis of MCDK by ultrasound (US) is very important. Traditionally, MCDK is diagnosed by 2-D US. Recently, 3-D US has emerged, and may overcome the weakness of 2-D US. In this series, we retrospectively analysed the cases of MCDK diagnosed by prenatal 2-D and 3-D US from November 1995 to March 2002 to evaluate the prenatal sonographic characteristics of this disease and to compare the efficacy of 2-D and 3-D US. The 2-D assessment included the lesion of MCDK, the amniotic fluid volume and associated anomalies. The 3-D assessment included three-orthogonal multiplanar views and various rendering modes of reconstruction of MCDK. In total, 28 cases were diagnosed by prenatal 2-D and 3-D US. Within the study period, 2-D US detected 100% of MCDK, as did 3-D US, and revealed that left, right and bilateral MCDK were in 46.4%, 28.6%, and 25% of cases, respectively. Oligohydromnios was present in 6 cases (21.4%). In addition, 3-D US showed fetal MCDK vividly and provided a whole view of the disease that assisted comprehension of the severity and extent better than 2-D US. In conclusion, although 2-D US detected all the cases of fetal MCDK in utero as did 3-D US, the 3-D images generated by various rendering modes can further assist in evaluating the severity and extent of MCDK, with a novel view that substantially aids the medical team in prenatal management and the parents in genetic consultation.