Three-dimensional sonographic volume measurement of the fetal cerebellum

Purpose The objective of this longitudinal study was to evaluate the growth of the fetal cerebellum in normal pregnancy by using three-dimensional ultrasound. Methods Three-dimensional sonographic examinations were performed for 13 appropriate-for-gestational-age fetuses. Fetal cerebellar volume was measured every 2 to 3 weeks after 20 weeks of gestational age until delivery. The common multiplanar technique was used to calculate the fetal cerebellar volume. Results A curvilinear relationship was found between gestational age and cerebellar volume (R² = 78.6%, P < 0.0001), and normal ranges of cerebellar volume measurements for estimating the growth of the fetal cerebellum during normal pregnancy were generated. The data gathered in this study were fairly comparable with previous data obtained using three-dimensional ultrasound. However, the normal ranges of cerebellar volume that we determined were relatively wide throughout pregnancy. Conclusions Our findings suggest that a standard curve for fetal cerebellar volume using three-dimensional ultrasound can play a role in the evaluation of normal cerebellar growth in the fetus. However, we do cast doubt on the reliability and reproducibility of cerebellar volume measurement using three-dimensional ultrasound. Further studies involving a larger sample size and another technique (the rotational method with VOCAL) would be needed to confirm these findings.     

MR超快速成像序列测量正常胎儿肾脏

目的 探讨MR超快速成像序列评估正常胎儿肾脏的可行性。方法 收集135胎肾脏发育正常胎儿的MR资料,测量肾脏长度（RL）、宽度（RW）、厚度（RT）、肾实质厚度（RPT）、肾盂宽度（RPW）和体积（RV）,分析上述参数测量的重复性及其与胎龄（GA）的关系。结果 RL、RW、RT、RPT、RPW在2名观察者间、同一观察者2次测量间、MR与超声两种测量方法间均具有较好的一致性,各参数测量值在双侧肾脏间差异无统计学意义（P均>0.05）。RL、RW、RT、RPT、RPW、RV与GA均呈正相关（r分别为0.95、0.87、0.86、0.77、0.44、0.90,P均<0.001）。在各参数与GA的回归方程中,RL的确定系数最大（R²=0.90）。结论 MR超快速成像序列用于正常胎儿肾脏检查中具有可行性,可弥补超声检查的不足,为临床决策提供更多有价值的影像学信息。     

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。     

Fetal renal volume in normal gestation: a three-dimensional ultrasound study

To establish a reference chart of fetal kidneys in normal pregnancy, we performed a prospective and cross-sectional study. A total of 152 singleton fetuses ranging between 20 and 40 weeks' gestation and meeting the criteria of normal pregnancies were included. Three-dimensional ultrasound (3-D US) was used to measure the fetal renal volume. Our results revealed that both renal volumes are highly correlated with the fetal gestational age. Using gestational age (GA) as the independent variable and right renal volume (RRV) as the dependent variable, the best-fit regression equation was RRV (mL)=0.74053xGA (week)-13.318 (r = 0.89, p < 0.001). Similarly, the best-fit equation for the left renal volume (LRV) was LRV (mL)=0. 76093xGA (week)-13.421 (r = 0.86, p < 0.001). The normal growth centiles of both kidneys were established based on these two equations. There were no significant differences of the volumes between bilateral kidneys. In conclusion, our data of fetal renal volumes assessed by 3-D US may serve as a reference in evaluating fetal renal growth.     

三维超声计算机辅助虚拟脏器分析技术评价胎儿胆囊发育

目的 探讨三维超声计算机辅助虚拟脏器分析(VOCAL)技术测量不同孕龄胎儿胆囊体积,建立胆囊体积的正常参考值范围,并评价其与孕周的相关性。方法 选择19~40孕周正常胎儿230胎作为研究对象,采用二维超声和三维超声测量胎儿胆囊体积,并观察其重复性和一致性,分析胆囊体积与孕周的相关性。结果 同一操作者和不同操作者应用三维超声的重复性和一致性均优于二维超声。胎儿胆囊体积随孕周增加而增大,回归方程为Y=-0.027+0.104X-0.005X²(r=0.774,P=0.0001)。结论 三维超声VOCAL技术在胎儿胆囊体积测量方面的重复性和一致性优于二维超声,有助于评价胎儿胆囊发育。     

Three‐Dimensional Ultrasonography of the Fetal Vermis at 18 to 26 Weeks' Gestation

Objective. The purpose of this study was to establish the normality of the fetal vermis, ie, the time of appearance of the primary fissure, as well as its measurements between 18 and 26 weeks' gestation, using 3‐dimensional (3D) ultrasonography. Methods. A prospective cross‐sectional study of normal singleton pregnancies was conducted. Examinations were performed with high‐resolution transabdominal ultrasonography using the axial plane in 173 fetuses between 18 and 26 weeks' gestation. Postprocessing measurements of the fetal vermis were done with 4‐dimensional software using static volume contrast imaging and tomographic ultrasound imaging in the C‐plane. Detection of the primary fissure was evaluated in all cases, and the time of appearance was documented. Results. Adequate vermis measurements were obtained in 173 fetuses. Vermian length as a function of gestational age was expressed by regression equations, and the correlation coefficients were found to be highly statistically significant (P < .001). The normal mean ± 2 SD for each gestational week was defined. The primary fissure was observed at 24 weeks' gestation in all cases, at 22 weeks in 94% of cases, and as early as 18 weeks in 40%. Conclusions. This 3D study documents the appearance of the primary fissure and presents the normal range of vermian measurements, confirming normal development of the fetal vermis starting as early as 18 weeks' gestation. It also shows an easy method for visualizing the vermis with 3D ultrasonography at every gestational week regardless of fetal presentation.     

Placental Volumes Measured by 3‐Dimensional Ultrasonography in Normal Pregnancies From 12 to 40 Weeks' Gestation

Objective. The purpose of this study was to construct nomograms of placental volumes according to gestational age and estimated fetal weight. Methods. From March to November 2007, placental volumes were prospectively measured by ultrasonography in 295 normal pregnancies from 12 to 40 weeks' gestation and correlated with gestational age and estimated fetal weight. Inclusion criteria were healthy women, singleton pregnancies with normal fetal morphologic characteristics on ultrasonography, and confirmed gestational age by first‐trimester ultrasonography. Results. The mean placental volume ranged from 83 cm³ at 12 weeks to 427.7 cm³ at 40 weeks. Linear regression yielded the following formula for the expected placental volumes (ePV) according to gestational age (GA): ePV (cm³) = ?64.68 + 12.31 × GA (r = 0.572; P < .001). Placental volumes also varied according to estimated fetal weight (EFW), and the following mathematical equation was also obtained by linear regression: ePV = 94.19 + 0.09 × EFW (r = 0.505; P < 0.001). Conclusions. Nomograms of placental volumes according to gestational age and estimated fetal weight were constructed, generating reference values.     

Normal fetal lung volume measured with three-dimensional ultrasound.

OBJECTIVES: To construct reference intervals for fetal lung volumes measured longitudinally using three-dimensional (3D) ultrasound, and to evaluate the effect of gender on lung size. METHODS: This was a prospective, longitudinal study in the obstetric outpatient department of the VU University Medical Center, Amsterdam. Seventy-eight women with uncomplicated pregnancies were scanned three to four times at gestational ages of 18-34 weeks. 3D models of the lung were constructed using the ultrasound machine's software. After the infants were delivered the entire group was reanalyzed with regard to fetal gender. Centiles for the lung volumes of the entire group and for each gender separately were estimated using multilevel modeling. RESULTS: Charts and tables of right and left fetal lung volumes, using gestational age and estimated fetal weight as the independent variables, are presented. There was a significant difference in lung volume between male and female fetuses at each gestational age. Charts and tables of right and left fetal lung volumes for each gender at gestational ages of 18-34 weeks are also presented. CONCLUSIONS: We present valid references for volumetric measurements of the right and left fetal lungs in male and female fetuses. The feasibility and reliability of fetal lung volume measurements using 3D ultrasound is good.     

Ultrasonographic assessment of growth and estimation of birthweight in late gestation fetal sheep

Our aim was to identify which ultrasound parameters can be most accurately measured and best predict ovine fetal weight in late gestation. Singleton pregnancies were established using embryo transfer in 32 adolescent ewes, which were subsequently overnourished to produce fetuses of variable size (1720–6260 g). Ultrasound measurements at 126–133 days gestation were compared with fetal weight/biometry at late-gestation necropsy (n = 19) or term delivery (n = 13). Abdominal circumference (AC) and renal volume (RV) correlated best with physical measurements (r = 0.78–0.83) and necropsy/birth weight (r = 0.79–0.84). Combination of AC + RV produced an estimated fetal weight equation [Log EFW = 2.115 + 0.003 AC + 0.12 RV – 0.005 RV²] with highest adjusted R² (0.72) and lowest mean absolute/percentage prediction error (396–550 g/11.1%–13.2%). In conclusion, AC and RV are parameters of choice for assessment of late-gestation ovine fetal growth and can be used to estimate fetal weight with similar accuracy to human fetuses.     

Doppler Velocimetry of the Ophthalmic Artery in Normal Pregnancy

Objective. This study aimed at analyzing the correlation between ophthalmic Doppler indices and gestational age (GA) in healthy patients with singleton pregnancies. Intraobserver reproducibility and right‐to‐left eye correlation were also evaluated. Methods. Healthy pregnant women (n = 289) at 20 to 40 weeks' GA were evaluated. The resistive index (RI), pulsatility index (PI), and peak ratio (PR) were determined by 2 measurements in each eye. Comparisons were performed first between the 2 measurements in each eye and later between the right and left eyes. Spearman rank correlation was used to analyze the relationship of the RI, PI, and PR with GA. Linear regression analysis was also performed. Results. No significant differences were found between the values obtained for the first and the second measurements in each eye and those for the RI, PI, and PR in the right and left eyes. There was a significant decrease in RI and PI values with advancing GA, however (ρ = ?0.264 and ?0.1192, respectively), with low R² values for both. Thus, only a small proportion of the variations observed in the RI and PI was associated with changes in GA. No significant difference was found between the PR values with regard to GA intervals. Conclusions. Doppler velocimetry is a reproducible technique for evaluation of the RI, PI, and PR in the ophthalmic artery. Unilateral analysis of these indices can be used. Linear regression analysis indicated that other factors were associated with a decrease in the RI and PI values with advancing GA. No significant change was observed in the PR values throughout normal pregnancy.     

Fetal Cerebellar Volume and Symmetry on 3-D Ultrasound: Volume Measurement with Multiplanar and Vocal Techniques

The purpose of this prospective longitudinal study was to evaluate the growth of the fetal cerebellar volume by means of 3-D ultrasound to evaluate whether there is a difference between the volumes of the left and right cerebellar hemispheres, and to evaluate the intra- and interobserver reliability of two different techniques of volume measurement. Three-dimensional ultrasound examinations were performed every two to three weeks on 27 fetuses between 20 and 40 weeks' gestation. Measurements of the total cerebellar volume and of the left and right cerebellar hemispheres were done using the multiplanar technique. Multilevel analysis was used to determine the growth of cerebellar volume based on individual developmental trajectories and compare the volume of the right and left hemispheres of the cerebellum. The intra- and interobserver reliability was calculated for the multiplanar and VOCAL™ techniques in a subgroup of 10 fetuses. A nonlinear growth curve of cerebellar volume in normal pregnancy was generated. The cerebellar growth per two-week decreased from a gain of 51% of the first measurement at 20 weeks to a gain of 16% of the first measurement at 38 weeks. The left cerebellar hemisphere was significantly larger (12.3%, p < 0.01) than the right. The intraclass correlation coefficient for the measurements by the two techniques was 0.99. Intraobserver reliability: the intraclass correlation coefficient for the measurements using the multiplanar technique was 0.96 and 0.97 and for VOCAL™ it was 0.98 and 0.97 for the two observers, respectively. Interobserver reliability: the intraclass correlation coefficient for the measurements using the multiplanar technique was 0.97 and for VOCAL™ 0.98. Longitudinal growth curves based on individual developmental trajectories were generated for the cerebellar volume. The left fetal cerebellar hemisphere was found to be significantly larger than the right. Both multiplanar and VOCAL™ techniques had a good intra- and interobserver reliability and yielded very similar results. (E-mail: l.pistorius@umcutrecht.nl)     

Comparison of B‐Mode Ultrasound, 3‐Dimensional Ultrasound,and Magnetic Resonance Imaging Measurements of Carotid Atherosclerosis

Objective. We compared the intraobserver and interscan variability of carotid atherosclerosis measured using B‐mode ultrasound for quantifying intima media thickness (IMT), 3‐dimensional ultrasound (3DUS) for quantifying vessel wall volume (VWV) and total plaque volume (TPV), and magnetic resonance imaging (MRI) for measuring VWV. We also evaluated the associations of these measurements and sample sizes required to detect specific changes in patients with moderate atherosclerosis. Methods. Ten patients were evaluated with B‐mode ultrasound, MRI, and 3DUS twice within 14 ± 2 days. Measurements of IMT, MRI VWV, 3DUS VWV, and 3DUS TPV were performed by single observers using manual (VWV and TPV) and semiautomated (IMT) segmentation. Results. Intraobserver coefficients of variation were 3.4% (IMT), 4.7% (3DUS VWV), 6.5% (MRI VWV), and 23.9% (3DUS TPV). Interscan coefficients of variation were 8.1% (MRI VWV), 8.9% (IMT), 13.5% (3DUS VWV), and 46.6% (3DUS TPV). Scan‐rescan linear regressions were significant for 3DUS TPV (R² = 0.57), 3DUS VWV (R² = 0.59), and IMT (R² = 0.75) and significantly different (P < .05) for MRI VWV (R² = 0.87). Conclusions. B‐mode ultrasound‐derived IMT provided the highest intraobserver and interscan reproducibility. Three‐dimensional measurements of VWV derived from 3DUS and MRI provided both high sensitivity and high intraobserver and interscan reliability.     

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 fetal cerebellar volume using three-dimensional ultrasound

The purposes of this study were to assess the fetal cerebellar volume during normal gestation using three-dimensional (3-D) ultrasound (US) and to establish a normal chart of fetal cerebellar volume using Altman's model of statistics. In total, 231 healthy fetuses were studied for assessment of cerebellar volume using a 3-D US volume scanner. The fetuses to be studied were selected to give a cross-sectional series (i.e., each fetus was examined only once). Polynomial regression analysis was calculated to find the best-fit model using gestational age as the independent variable and cerebellar volume as the dependent variable. Altman's model was used to calculate the age-related reference centiles for the variance of cerebellar volume. In addition, common fetal growth indices, such as biparietal diameter, occipitofrontal diameter, head circumference, abdominal circumference, femur length and estimated fetal weight, were also measured for the correlation between cerebellar volume and these indices. Our results indicated that the fetal cerebellar volume was highly correlated with gestational age in normal pregnancies with the best-fit polynomial regression equation of a second-order (r = 0.91, p < 0.0001). In addition, fetal cerebellar volume in normal gestation is also highly correlated with common fetal growth indices, such as biparietal diameter, occipitofrontal diameter, head circumference, abdominal circumference, femur length and estimated fetal weight (all p < 0.0001). Following the Altman's model, a normal growth chart of fetal cerebellar volume was established for clinical reference. In conclusion, with 3-D US, the assessment of fetal cerebellar volume becomes feasible. We believe that fetal cerebellar volume assessed by 3-D US may be useful in detecting cerebellar hypoplasia and relevant syndromes prenatally.     

Three-dimensional sonography of prenatal skull base development.

OBJECTIVE: To explore longitudinally the development of the fetal skull base using three-dimensional (3D) sonography. METHODS: Serial 3D sonographic measurements of anterior skull base length, posterior cranial fossa length and skull base angle were made in 126 normal singleton pregnancies at 18-34 weeks of gestation. In a sub-study of 22 pregnancies, intraobserver variability was determined. Regression analysis for repeated measurements was performed by means of the random coefficients model. Results from an earlier publication on brain volume were extended to the total patient cohort. RESULTS: Measurements were technically successful in 69-94% of cases. The coefficient of variation for differences between repeated tests within women was 3.5-7.6% and between repeated analyses of the same recorded volume it was 3.0-5.1%. A statistically significant gestational age-related increase was established for both the anterior skull base length and the posterior cranial fossa length and the skull base angle showed a small but significant flexion of about 6 degrees . A higher increment in posterior cranial fossa length relative to anterior skull base angle was established. A significant quadratic relationship could be established for both anterior skull base length (P < 0.0001) and posterior cranial fossa length (P < 0.0001) but not for skull base angle, relative to brain volume. CONCLUSION: The reproducibility was acceptable for all fetal skull base measurements. The more pronounced growth in posterior cranial fossa length relative to anterior skull base length is influenced by brain growth. The small flexion of the skull base angle, however, may be caused by other factors. Published by John Wiley & Sons, Ltd.     

时空关联成像-M模式评价胎儿右心室收缩功能

目的 应用时空关联成像-M模式(STIC-M)评价正常胎儿右心室收缩功能。方法 对胎儿正常的150名孕妇进行STIC-M检测,测量胎儿三尖瓣半环平面收缩位移(f-TAPSE);应用体器官计算机辅助分析自动测量技术测量胎儿右心室舒张末期容积和收缩末期容积,计算右心室每搏输出量和射血分数(RVEF),分析胎儿f-TAPSE、孕周、RVEF之间的相关性。结果 f-TAPSE与孕周呈显著正相关(r=0.964,P<0.01),与RVEF之间无相关性(r=0.040,P=0.773);胎儿RVEF相对恒定,不随孕周增加而变化,与孕周之间无相关性(r=-0.231,P=0.310)。结论 STIC-M评价正常胎儿右心室收缩功能简单、重复性好,值得临床推广应用。     

孕早期超声测量胎儿腹主动脉与肠系膜上动脉夹角用于预测先天性膈疝北大核心CSCD

目的观察孕早期采用超声测量胎儿腹主动脉与肠系膜上动脉(SMA)夹角(AS角)预测先天性膈疝(CDH)的价值。方法纳入206胎接受超声检查的孕早期胎儿,其中200胎正常,5胎经随访证实为CDH、1胎为巨大脐膨出;测量胎儿AS角及头臀长(CRL)。以组内相关系数(ICC)评价观察者间测量结果的一致性;采用Pearson相关性评价正常胎儿AS角与CRL的相关性。结果2名观察者测量AS角及CRL的一致性良好(ICC均>0.75,P均<0.05)。正常胎儿AS角平均为(37.02±9.41)°,AS角与CRL无明显相关(R^(2)=0.0004,P=0.783)。5胎CDH中,3胎为孤立性左侧膈疝,1胎为左侧膈疝合并多发畸形,1胎为右侧膈疝合并多发畸形,孕早期AS角均明显增大(73°~119°)。1胎孕早期SMA走行明显异常,AS角150°,超声诊断为巨大脐膨出。结论超声测量孕早期胎儿AS角操作简便,且不受胎儿大小影响;AS角增大可能对预测胎儿CDH具有一定价值。     

时间-空间相关成像联合组织多普勒超声观察妊娠期糖尿病孕妇胎儿心脏结构和功能

目的 探讨时间-空间相关成像（STIC）联合组织多普勒（TDI）超声检测妊娠期糖尿病（GDM）孕妇胎儿心脏结构和功能的应用价值。方法 选取140例GDM孕妇（胰岛素治疗组40例,饮食控制组62例,血糖控制不良组38例）和211名正常妊娠孕妇（对照组）。应用STIC后处理获得M型图像（STIC-M型）,测量胎儿左、右心室壁和室间隔收缩末期和舒张末期厚度,以TDI测量胎儿心脏房室瓣环舒张早期运动速度（Ea）、舒张晚期运动速度（Aa）及收缩期运动速度（Sa）,并计算Ea/Aa值,比较4组间参数的差异。结果 4组间胎儿左、右心室壁及室间隔舒张末期和收缩末期厚度总体差异均有统计学意义（P均<0.05）,GDM各组均大于对照组（P均<0.05）,GDM各组间差异均无统计学意义（P均>0.05）。4组间二尖瓣环Ea/Aa总体差异有统计学意义（P=0.002）,GDM各组二尖瓣环Ea/Aa均小于对照组（P均<0.05）,GDM各组间差异无统计学意义（P均>0.05）。4组间三尖瓣环Ea/Aa、二尖瓣环Sa、三尖瓣环Sa总体差异均无统计学意义（P均>0.05）。结论 GDM孕妇胎儿心室壁及室间隔厚度增加,心脏舒张功能降低,血糖控制情况的差异对胎儿心肌厚度和心脏功能改变无显著影响。STIC-M型联合TDI超声技术对评估GDM孕妇胎儿心脏结构和功能具有一定应用价值。     

Reference values for left and right ventricular systolic-to-diastolic duration ratio (SDR) found using both spectral and tissue Doppler of fetal heart between 20 and 36+6 weeks of gestation

Purpose

To establish reference values for the systolic-to-diastolic duration ratio (SDR) of the left ventricle (LV) using spectral Doppler, as well as for the SDR’ of the interventricular septum (SEP), LV, and right ventricles (RV) using tissue Doppler of the fetal heart.

Method

This prospective and cross-sectional study evaluated 374 low-risk singleton pregnancies from 20 to 36 + 6 weeks of gestation. The ventricular filling time (FT) was obtained from LV inflow using spectral Doppler. Tissue Doppler was used to assess the FT of each ventricle by placing the cursor at the atrioventricular junction marked by the mitral and tricuspid valves, respectively. SDR was calculated as the sum of the isovolumic contraction time (ICT) and the ejection time (ET) divided by the sum of the isovolumic relaxation time (IRT) and the ventricular FT. We used regression analysis to obtain the best-fit model polynomial equation for the parameters. The concordance correlation coefficient (CCC) was used to assess intra- and inter-observer reproducibility.

Results

SDR and SDR’ LV showed a progressive decrease with gestational age (GA); the SDR’ RV and SDR’ SEP did not show a significant decrease with advancing GA. The SDR LV (r = 0.29, p < 0.0001), SDR’ RV (r = 0.21, p < 0.0001), SDR’ LV (r = 0.20, p = 0.0001), and SDR’ SEP (r = 0.25, p < 0.0001) showed a significant weak positive correlation with fetal heart rate. The inter-observer SDR’ SEP measurements demonstrated poor reproducibility (CCC: 0.50), whereas intra-observer SRD LV measurements demonstrated moderate reproducibility (CCC: 0.78).

Conclusions

Reference values for SDR SEP, LV, and RV using spectral and tissue Doppler of fetal heart were established between 20 and 36+6 weeks of gestation.