三维超声体积自动测量技术评估肺血减少型先天性心脏病胎儿肺体积变化

目的 采用三维超声计算机辅助虚拟脏器分析（VOCAL）技术观察肺血减少型先天性心脏病（CHD-DPBF）对胎儿肺体积发育的影响。方法 收集41胎法洛四联症（TOF）胎儿（TOF组）和110胎正常胎儿（对照组），以二维超声估测胎儿孕周、体质量及心胸比（CTR），以三维超声VOCAL技术测量胎儿肺体积，计算超声肺重比（肺体积与体质量的比值）和肺体积与孕周比值，比较2组间的差异；评估胎儿肺体积与孕周的相关性。结果 TOF组胎儿孕周、估算体质量和肺体积与对照组比较差异无统计学意义（P均>0.05），TOF组胎儿CTR大于对照组（P<0.001），胎儿肺体积与孕周比值及超声肺重比小于对照组（P均<0.05）。TOF组及对照组胎儿肺体积与孕周均呈正相关（r=0.611、0.547，P均<0.001）。结论 CHD-DPBF胎儿超声肺重比及肺体积与孕周比值均低于正常胎儿，提示CHD-DPBF胎儿肺脏发育受到一定程度不良影响。     

Pulmonary artery diameters in healthy fetuses from 19 to 40 weeks' gestation.

OBJECTIVE: The purpose of this study was to construct nomograms for diameters of the fetal main pulmonary artery (MPA), right pulmonary artery (RPA), and left pulmonary artery (LPA) according to gestational age (GA) and estimated fetal weight (EFW). METHODS: Between May 2005 and February 2006, MPA and branch artery diameters were prospectively estimated with ultrasonography in 220 healthy fetuses from 19 to 40 weeks' gestation and correlated with GA and EFW. RESULTS: Mean MPA, RPA, and LPA diameters ranged from 2.93, 1.71, and 1.66 mm, respectively, at 19 weeks to 9.23, 5.49, and 5.65 mm at 40 weeks. Linear regression yielded the following formulas for the expected diameters according to GA: MPA=-2.77 + 0.30 x GA; RPA=-1.71 + 0.18 x GA; and LPA=-1.95 + 0.19 x GA. The following formulas were obtained by logarithm distribution for the expected diameters according to EFW: MPA=-1.165 + 0.247 x log of estimated fetal weight (lnFW); RPA=-0.651 + 0.141 x lnFW; and LPA=-0.718 + 0.150 x lnFW. CONCLUSIONS: Nomograms of MPA and branch pulmonary artery diameters according to GA and EFW have been described, generating reference values.     

Is there a relationship between estimated fetal weight and umbilical artery Doppler impedance indices?

OBJECTIVE: To establish whether there is a relationship between estimated fetal weight (EFW) and umbilical artery Doppler waveform impedance indices in the third trimester. METHODS: The pulsatility index (PI) and S/D (systolic/diastolic) ratio were obtained together with the EFW from 274 low-risk pregnancies. Measurements were made at fortnightly intervals from 30 weeks' gestation until delivery. A relationship between the two impedance indices and EFW was sought at gestational age ranges of 30-32, 33-35, 36-38 and 39-41 weeks. RESULTS: There were 918 pairs of PI (with S/D) and EFW available for analysis. The mean of the impedance indices decreased with advancing gestational age as expected. There was no clinically relevant correlation between impedance indices and EFW within any of the gestational age ranges. CONCLUSION: Impedance indices from the umbilical artery Doppler waveform decrease with advancing gestational age due, at least partially, to expansion of the placental vascular tree. Within narrow gestational age ranges in the third trimester, there is no meaningful correlation between fetal weight and impedance indices. It is therefore not necessary to adjust umbilical artery Doppler impedance indices to account for fetal size.     

Accuracy of sonographically estimated fetal weight in 840 women with different pregnancy complications prior to induction of labor.

OBJECTIVES: To evaluate the accuracy of sonographically estimated fetal weight (EFW) shortly before induction of labor in the presence of different pregnancy complications, and to define possible variables affecting it. METHODS: The study sample consisted of 840 women with singleton pregnancies and cephalic presentation who were admitted to our unit for induction of labor between January 1999 and December 2000. All underwent detailed ultrasound assessment for EFW, amniotic fluid index, biophysical profile and placental location. Indications included previous Cesarean section, postdate pregnancy, pregnancy-induced hypertension, diabetic pregnancy, suspected large-for-gestational age (LGA) infants, suspected fetal growth restriction (FGR), oligohydramnios, decreased fetal movements, premature rupture of membranes at or before term. EFW was calculated after measuring fetal abdominal circumference and femur length. The EFW was compared with the weight at delivery, 1-3 days later. RESULTS: There was a high correlation between EFW and birth weight (R(2) = 0.775, P < 0.001). The mean birth weight was 3207 +/- 561 g, and mean absolute weight difference was 227 +/- 197 g; (absolute range, 0-1700 g; actual range, - 986 to + 1700 g). The mean weight difference was significantly different between the patients with LGA infants, FGR infants and preterm premature rupture of membranes (PPROM) (- 110 +/- 281 g, + 113 +/- 195 g and + 115 +/- 307 g, respectively, P < 0.01). Stepwise linear regression analysis of the effects of maternal and pregnancy characteristics on the weight difference yielded lower gestational age, higher birth weight, anterior placenta, higher gravidity, and younger maternal age as independent and significant variables associated with greater actual weight difference inaccuracy (R(2) = 0.099, P < 0.001), and higher birth weight as the only independent and significant variable associated with greater absolute weight difference (R(2) = 0.09, P = 0.018). CONCLUSIONS: The sonographic EFW is highly correlated with birth weight. However, clinicians should be aware of the risk of overestimation in pregnancies with suspected LGA and underestimation in pregnancies with PPROM and suspected FGR.     

正常双绒毛膜双胎孕期估重差异性及其影响因素

目的 探讨正常双绒毛膜双胎孕期超声估重（EFW）差异率及其影响因素。方法 回顾性分析550名正常双绒毛膜双胎（1 100胎）孕妇的产前孕期超声生物测量指标,并根据胎儿双顶径、头围、腹围、股骨长计算双胎EFW差异率,分析其与孕周的关系,观察性别、受孕方式（试管组与非试管组）是否影响EFW差异率。结果 正常双绒毛膜双胎EFW差异率总体呈偏态分布,中位数为6.56%,四分位间距为8.92%,第95百分位数为20.81%,与孕周无明显相关。性别相同组与性别不同组、不同受孕方式组间双胎EFW差异率差异均无统计学意义（P均>0.05）。结论 产前超声对双绒毛膜双胎估重有重要参考价值,EFW差异率可作为双绒毛膜双胎孕期生长评估相对恒定的指标。     

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.     

Association of amniotic fluid index with estimated fetal weight.

OBJECTIVE: The relationship between amniotic fluid volume and gestational age has been described previously. The association of body weight and urine output has been observed in human neonates. Our goal was to assess the correlation of the amniotic fluid index (AFI) with estimated fetal weight (EFW) in the third trimester. METHODS: We conducted a retrospective observational study on 426 pregnant women with singleton gestations who were referred to our unit for sonographic evaluation in the third trimester. The AFI, EFW, and EFW percentile corrected for gestational age were evaluated. The sonographic examinations were stratified into 3 gestational age categories: 28 through 33.9 weeks, 34 through 37.9 weeks, and 38 weeks and later. Maternal and fetal outcome variables were collected from medical records. Linear regression, Mann-Whitney U, and Kruskal-Wallis tests were used for statistical analysis. RESULTS: There was no significant relationship between the AFI and EFW in the entire group of patients (R = 0.08; P = .096). There was a significant relationship between the AFI and EFW after 38 weeks' gestation (R = 0.30; P = .003). In addition, in female fetuses the EFW percentile correlated with higher AFI values at all gestational ages (R = 0.31; P < .001); this, however, was not observed in male fetuses. CONCLUSIONS: There is no relationship between the AFI and EFW during the third trimester, although a positive relationship between the AFI and EFW was noted late in gestation. In pregnancies with female fetuses, the AFI was positively associated with EFW percentile before 38 weeks' gestation.     

Assessment of placental fractional moving blood volume using quantitative three-dimensional power doppler ultrasound

To test the hypothesis that the placental fractional moving blood volume is different with advancing gestational age (GA), we assessed the vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) of the placenta in normal pregnancy by using three-dimensional (3-D) power Doppler ultrasound (US). We enrolled 100 healthy pregnant women with gestational age between 20 to 40 weeks for this study. Three-dimensional power Doppler ultrasonography was used to assess the VI, FI and VFI in each case. Our results showed that the linear regression equations for VI, FI and VFI, by using GA as the independent variable, were VI = 0.27107 x GA -4.02748 (r = 0.84, p < 0.0001), FI = 0.56115 x GA + 34.28945 (r = 0.49, p < 0.001), and VFI = 0.15663 x GA -2.53810 (r = 0.82, p < 0.0001), respectively. In addition, the VI, FI and VFI values of the placental flow were also positively correlated with the fetal growth indices, namely, biparietal diameter, occipitofrontal diameter, head circumference, abdominal circumference and estimated fetal weight (all p values < 0.001). In conclusion, our study illustrates that the fractional moving blood volume of the placenta is positively correlated with the increment of gestational age and the fetal growth indices. Our data may be used as a reference in the assessment of the placental fractional moving blood volume using the quantitative 3-D power Doppler US.     

A nomogram of fetal lung volumes estimated by 3-dimensional ultrasonography using the rotational technique (virtual organ computer-aided analysis).

OBJECTIVE: The purpose of this study was to build a nomogram of normal fetal lung volumes throughout gestational age estimated by 3-dimensional ultrasonography using the rotational technique (Virtual Organ Computer-Aided Analysis [VOCAL]; GE Healthcare, Kretztechnik, Zipf, Austria). METHODS: Fetal lung volume was assessed in 146 healthy fetuses by 3-dimensional ultrasonography using the technique of rotation of the multiplanar imaging (VOCAL). Inclusion criteria were healthy women with singleton normal pregnancies, normal fetal morphologic ultrasonographic findings, reliable dating established by dates and by ultrasonographic measurement of the crown-lump length in the first trimester, and gestational age from 20 to 37 weeks. Exclusion criteria were discordance between clinical and ultrasonographic dating, patients lost to follow-up, and birth weight disorders. Each patient was scanned once during pregnancy. RESULTS: The right, left, and total mean pulmonary volumes ranged, respectively, from 5.37, 4.66, and 9.95 cm3 at 20 weeks to 46.06, 37.34, and 84.35 cm3 at 37 weeks. The logistic transformation analysis yielded the following formulas: right lung volume = exp(4.07/[1 + exp(21.90 - gestational age/5.44)]); left lung volume = exp(3.82/(1 + exp[22.03 - gestational age/5.17)]); and, total lung volume = exp(4.72/[1 + exp(20.30 - gestational age/6.05)]). CONCLUSIONS: A new nomogram of fetal lung (right, left, and total) volumes throughout gestational age using the rotational technique (VOCAL) is described, and reference values have been generated.     

三维超声评估胎儿心室壁体积的可行性

目的 探讨三维超声时空相关成像（STIC）及虚拟器官计算机辅助分析（VOCAL）技术评估胎儿心室壁体积的可行性。方法 测量247胎22~32⁺⁶周正常胎儿心室壁体积,采用组内相关系数（ICC）分析观察者内及观察者间一致性。测量14胎心脏异常胎儿数据进行有效性验证。结果 胎儿心脏平均室壁体积与孕周具有良好相关性,左心室壁体积=－6.542+0.339×孕周（r²=0.98）,右心室壁体积=－7.509+0.384×孕周（r²=0.74）。右心室壁体积（ICC=0.994、0.888）及左心室壁体积（ICC=0.995、0.972）的观察者内及观察者间一致性良好。14胎心脏异常胎儿中,6胎心室壁体积发生改变（小于第5或大于第95百分位数）。结论 STIC及VOCAL技术可用于估测胎儿心室壁体积的参考范围,可重复性良好。     

Reference values for Doppler velocimetric indices from the fetal and placental ends of the umbilical artery during normal pregnancy

A range-gated Doppler ultrasound system combined with a real-time imaging system was used to determine arterial blood velocity values from the fetal and placental ends of the umbilical cord in 269 normal pregnancies between 17 and 40 weeks, menstrual age. The systolic–diastolic ratio (S/D), pulsatility index (PI), and resistance index (RI) were higher at the fetal end compared to the placental end of the cord. The individual differences in these Doppler indices, obtained between the fetal and placental recording sites, were inversely related to menstrual age: S/D: r = ?0.38, p < 0.001; PI: r = ?0.25, p < 0.001; and RI: r = ?0.15, p < 0.01. After normalization for the angle of insonation, the peak systolic velocity was higher and the enddiastolic velocity was lower at the fetal than at the placental end of the cord. It is concluded that routine recordings for Doppler velocimetric indices should take into account the recording site on the umbilical cord in order to reduce methodological sources of variance, especially during midgestation. Furthermore, the data presented here in the form of the median and percentile values are proposed as normal reference values to facilitate this procedure. © 1993 John Wiley & Sons, Inc.     

Use of Multiplanar 3‐Dimensional Ultrasonography for Prenatal Sex Identification

Objective. Determination of fetal sex is an important part of detailed second‐trimester ultrasonography. This task can be hindered by the fetal position, a low amniotic fluid volume, and advanced gestational age. Identification of fetal sex is further important in multiple gestations and prior histories of indeterminate‐sex pregnancies. The goal of the study was to compare the effectiveness of 2‐dimensional ultrasonography (2DUS) versus 3‐dimensional ultrasonography (3DUS) at sex identification and to determine how genitalia measurements taken with 3DUS technology compare with measurements taken with 2DUS. Methods. A total of 111 patients at or beyond 16 weeks' gestation were recruited. Assignments of fetal sex using 2DUS and 3DUS were compared by the test of proportions. The actual neonatal sex was obtained after delivery. Given such small number of misdiagnoses by either 2DUS or 3DUS, the accuracies of the two modalities were not found to be statistically distinguishable from one another (P = .5585). The penile length, scrotal width, and bilabial diameter according to gestational age were measured and compared with previously published 2DUS data by t tests. Results. Sexes were assigned and interpreted in 65 cases. Ranges of genitalia measurements were plotted against gestational age and were found to be comparable with published data. There was a dramatic difference between the bilabial diameter and scrotal width with advancing gestational age that made sex determination much easier in the third trimester. Conclusions. Although 3DUS did not have better prediction of fetal sex when compared with 2DUS, it may be a useful tool in conjunction with traditional imaging techniques in assigning fetal sex.     

Three-dimensional sonographic measurement of fetal renal volume

Objective The objective of this longitudinal study was to evaluate the growth of the fetal kidney in normal pregnancies using three-dimensional ultrasound. Methods Three-dimensional sonographic examinations were performed on 13 appropriate-for-gestational-age fetuses. Fetal renal volume was measured every 2 to 3 weeks after 20 weeks gestational age until delivery. Results There was a good linear correlation between left and right renal volumes (r = 0.9614, P < 0.0001). Curvilinear relationships were found between gestational age and left and right renal volume (left: R² = 79.1%, P < 0.0001; right: R² = 74.2%, P < 0.0001), and normal ranges of left and right renal volume measurements for estimating the growth of the fetal kidney during normal pregnancy were generated. There was a difference for each predicted value of the fetal renal volume in the third trimester of pregnancy in our study and in two other previous studies. The left and right fetal renal volume to estimated fetal weight ratios were constant during the pregnancies studied. Conclusion Our findings suggest that fetal renal volume measurement plays a role in assessment of the growth of fetal kidneys. However, we are doubtful about the reproducibility of fetal renal volume measurements made by using three-dimensional ultrasound in utero. Further studies involving larger sample sizes are needed to reevaluate the usefulness and reproducibility of fetal renal volume measurements.     

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.     

构建正常胎儿心胸比Z评分模型

目的 构建正常胎儿心胸比（CTR）Z评分模型,包括横径比（CTR1）、周长比（CTR2）和面积比（CTR3）。方法 对954胎孕11~40⁺⁶周正常胎儿行产前超声检查,于标准切面测量CTR作为因变量,以胎体大小参数,包括孕周（GA）、双顶径（BPD）及股骨长度（FL）为自变量,行回归分析,获得CTR均数回归方程;并分析CTR残差,以确定CTR标准差的最佳回归方程;根据公式计算CTR Z评分。结果 正常胎儿CTR与GA、BPD及FL均呈正相关（r=0.74~0.86,P均<0.05）;胎儿CTR参数与胎体大小参数的最佳拟合方程均为直线回归方程。成功构建了基于胎体大小参数CTR均数的拟合回归方程;CTR残差分析结果提示CTR标准差不随胎体大小变化而改变,均为恒定值标准差;根据方程可计算正常胎儿CTR Z评分。结论 基于GA、BPD及FL建立的正常胎儿CTR Z评分模型可为产前评估胎儿发育提供参考。     

胎儿生长发育受限的超声诊断与监测

胎儿生长受限指因胎盘功能不全导致胎儿生长未能达到其生物学潜能。目前临床最大困惑是如何鉴别胎儿生长受限与健康小于胎龄儿。超声为诊断胎儿生长受限的金标准,主要诊断指标包括估重、腹围及脐动脉血流频谱。超声监测有助于预测胎儿不良结局,协助判断分娩时机。目前已被证明可帮助评估患儿预后的监测指标包括估重、腹围等生长径线、脐动脉血流阻力指数、静脉导管血流频谱、大脑中动脉频谱、脑胎盘血流比率、子宫动脉血流阻力指数。     

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.     

Is there any relation between umbilical artery and vein diameter and estimated fetal weight in healthy pregnant women?

Purpose

The aim of this study was to investigate the relation between umbilical vessel diameter and estimated fetal weight (EFW) and other fetal biometric parameters, and to assess the role of umbilical vessel diameter in prediction of EFW. Umbilical vein/umbilical artery (UV/UA) ratio and its relation to EFW were also examined.

Methods

A prospective study was designed to assess the sonographic diameter of UA and UV in 720 low-risk pregnant women at 20–40?weeks’ gestation. Fetal biometry, EFW, and umbilical vessel measurements were performed.

Results

There were strong correlations between umbilical vessel diameter versus gestational age and EFW. Umbilical vessel diameters increased linearly up to 34?weeks, after which they plateaued. No relation was found between EFW versus UV/UA ratio and gestational age versus UV/UA.

Conclusion

Based on these findings, it is not possible at present to recommend the use of umbilical vessel diameters for prediction of EFW after 34?weeks, but it may be helpful under 34?weeks. UV/UA ratio is not useful for prediction and management of complicated pregnancies.     

Comparison of Estimated Fetal Weights Using Volume and 2‐Dimensional Sonography and Their Relationship to Neonatal Markers of Fat

Objective. The purpose of this study was to compare the accuracy of traditional 2‐dimensional sonographically estimated fetal weight (EW2D) with 3‐dimensional volume‐based estimated fetal weight (EW3D) and to evaluate the relationship between fetal limb volume, birth weight, and markers of neonatal adiposity. Methods. Fifty singleton pregnancies at 32 to 42 weeks' gestation underwent sonographic evaluation within 48 hours of delivery. We compared the accuracy of the EW2D and EW3D in the prediction of birth weight. The Ponderal index, sum of all skin fold measurements, estimated neonatal fat mass, and percent body fat were calculated. Paired t tests, simple regression analyses, a χ² test, and the Steiger z test were used where appropriate. P < .05 was considered significant. Results. The mean birth weight ± SD was 3130 ± 589 g at 38.8 ± 2.1 weeks. The EW2D (r² = 0.66) and EW3D (r² = 0.76) estimates were both correlated with birth weight. The birth weight and neonatal fat mass were more highly correlated with the sonographically based thigh volume (r² = 0.67 and 0.61) than femur length (r² = 0.41 and 0.37). The mean percent error between EW2D and birth weight was larger (?3.3% ± 11.6%) than the mean percent error of EW3D (0.7% ± 9.2%; P = .0004). Conclusions. Sonographically based fetal limb volumes, especially the fractional thigh volume, reflect neonatal fat mass and are better correlated with birth weight.