Measurement of limb circumferences with three-dimensional ultrasound for fetal weight estimation

Two-dimensional fetal biometry versus three-dimensional fractional thigh volume for ultrasonographic prediction of birthweight

OBJECTIVE

To develop and validate birthweight prediction models using fetal fractional thigh volume (TVol) in an Indian population, comparing them with existing prediction models developed for other ethnicities.

METHODS

A prospective observational study was conducted among 131 pregnant women (>36 weeks) attending a tertiary hospital in New Delhi, India, for prenatal care between December 1, 2014, and November 1, 2016. Participants were randomly divided into formulating (n=100) and validation (n=31) groups. Multiple regression analysis was performed to generate four models to predict birthweight using various combinations of two-dimensional (2D) ultrasonographic parameters and a three-dimensional (3D) ultrasonographic parameter (TVol). The best fit model was compared with previously published 2D and 3D models.

RESULTS

The best fit model comprised biparietal diameter, head circumference, abdominal circumference, and TVol. This model had the lowest mean percentage error (0.624 ± 8.075) and the highest coefficient of determination (R² =0.660). It correctly predicted 70.2% and 91.6% of birthweights within 5% and 10% of actual weight, respectively. Compared with previous models, attributability for the 2D and 3D models was 0.65 and 0.55, respectively. Accuracy was -0.05 ± 1.007 and -2.54 ± 1.11, respectively.

CONCLUSION

Models that included TVol provided good prediction of birthweight in the target population.

Effects of maternal tobacco-smoke exposure on fetal growth and neonatal size

Exposure to tobacco smoke, through both active and passive measures, has a significant impact on women's health, including effects on the cardiovascular, pulmonary and reproductive systems. Of particular interest is the effect of smoking on pregnancy outcomes. One crucial outcome that has been linked to the subsequent development of both neonatal and adult disease is intrauterine or fetal growth restriction. In this article, we will summarize the effects of smoking on newborn size and fetal growth. We will review evidence showing that tobacco consumption during pregnancy leads to a reduction in birthweight, largely through affecting specific anthropometric measures and newborn body composition. We will highlight the role of genetic susceptibility to these effects and discuss how smoking cessation prior to the third trimester results in a reduction in the risk of fetal growth restriction.

Weight estimation by three-dimensional ultrasound imaging in the small fetus

OBJECTIVES

To improve birth weight estimation in fetuses weighing <or= 1600 g at birth by deriving a new formula including measurements obtained using three-dimensional (3D) sonography.

METHODS

In a prospective cohort study, biometric data of 150 singleton fetuses weighing <or= 1600 g at birth were obtained by sonographic examination within 1 week before delivery. Exclusion criteria were multiple pregnancy, intrauterine death as well as major structural or chromosomal anomalies. A new formula was derived using our data, and was then compared with currently available equations for estimating weight in the preterm fetus.

RESULTS

Different statistical estimation strategies were pursued. Gradient boosting with component- wise smoothing splines achieved the best results. The resulting new formula (estimated fetal weight = 656.41 + 1.8321 x volABDO + 31.1981 x HC + 5.7787 x volFEM + 73.5214 x FL + 8.3009 x AC - 449.8863 x BPD + 32.5340 x BPD(2), where volABDO is abdominal volume determined by 3D volumetry, HC is head circumference, volFEM is thigh volume determined by 3D volumetry, FL is femur length and BPD is biparietal diameter) proved to be superior to established equations in terms of mean squared prediction errors, signed percentage errors and absolute percentage errors.

CONCLUSIONS

Our new formula is relatively easy to use and needs no adjustment to weight percentiles or to fetal lie. In fetuses weighing <or= 1600 g at birth it is superior to weight estimation by traditional formulae using two-dimensional measurements.

What does 2-dimensional imaging add to 3- and 4-dimensional obstetric ultrasonography?

OBJECTIVE

The purpose of this study was to determine whether 2-dimensional (2D) ultrasonography adds diagnostic information to that provided by the examination of 3-dimensional/4-dimensional (3D/4D) volume data sets alone.

METHODS

Ninety-nine fetuses were examined by 3D/4D volume ultrasonography. Volume data sets were evaluated by a blinded independent examiner who, after establishing an initial diagnostic impression by 3D/4D ultrasonography, performed a 2D ultrasonographic examination. The frequency of agreement and diagnostic accuracy of each modality to detect congenital anomalies were calculated and compared.

RESULTS

Fifty-four fetuses with no abnormalities and 45 fetuses with 82 anomalies diagnosed by 2D ultrasonography were examined. Agreement between 3D/4D and 2D ultrasonography occurred for 90.4% of the findings (123/136; intraclass correlation coefficient, 0.834; 95% confidence interval, 0.774-0.879). Six anomalies were missed by 3D/4D ultrasonography when compared to 2D ultrasonography (ventricular septal defect [n = 2], interrupted inferior vena cava with azygous continuation [n = 1], tetralogy of Fallot [n = 1], horseshoe kidney [n = 1], and cystic adenomatoid malformation [n = 1]). There were 2 discordant diagnoses: transposition of the great arteries diagnosed as a double-outlet right ventricle and pulmonary atresia misinterpreted as tricuspid atresia on 3D/4D ultrasonography. One case of occult spinal dysraphism was suspected on 3D ultrasonography but not confirmed by 2D ultrasonography. When compared to diagnoses performed after delivery (n = 106), the sensitivity and specificity of 3D/4D ultrasonography (92.2% [47/51] and 76.4% [42/55], respectively) and 2D ultrasonography (96.1% [49/51] and 72.7% [40/55]) were not significantly different (P = .233).

CONCLUSIONS

Information provided by 2D ultrasonography is consistent, in most cases, with information provided by the examination of 3D/4D volume data sets alone.

Three- and 4-dimensional ultrasound in obstetric practice: does it help?

OBJECTIVE

The purpose of this article was to review the published literature on 3-dimensional ultrasound (3DUS) and 4-dimensional ultrasound (4DUS) in obstetrics and determine whether 3DUS adds diagnostic information to what is currently provided by 2-dimensional ultrasound (2DUS) and, if so, in what areas.

METHODS

A PubMed search was conducted for articles reporting on the use of 3DUS or 4DUS in obstetrics. Seven-hundred six articles were identified, and among those, 525 were actually related to the subject of this review. Articles describing technical developments, clinical studies, reviews, editorials, and studies on fetal behavior or maternal-fetal bonding were reviewed.

RESULTS

Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, especially facial clefts. There is also evidence that 3DUS provides additional diagnostic information in neural tube defects and skeletal malformations. Large studies comparing 2DUS and 3DUS for the diagnosis of congenital anomalies have not provided conclusive results. Preliminary evidence suggests that sonographic tomography may decrease the examination time of the obstetric ultrasound examination, with minimal impact on the visualization rates of anatomic structures.

CONCLUSIONS

Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, evaluation of neural tube defects, and skeletal malformations. Additional research is needed to determine the clinical role of 3DUS and 4DUS for the diagnosis of congenital heart disease and central nervous system anomalies. Future studies should determine whether the information contained in the volume data set, by itself, is sufficient to evaluate fetal biometric measurements and diagnose congenital anomalies.

Fetal upper arm volume in predicting intrauterine growth restriction: a three-dimensional ultrasound study

As fetuses with intrauterine growth restriction (IUGR) may have increased risks with perinatal morbidity and mortality, prenatal diagnosis of IUGR is a very important issue in perinatology. To assess the efficacy of fetal upper arm volume in predicting IUGR, we undertook a prospective, cross-sectional study using quantitative three-dimensional (3D) ultrasound (US). In total, 40 fetuses with IUGR and 442 fetuses without IUGR were included for the upper arm volume assessment in utero by 3D US. All the fetuses were singletons and were followed up to delivery to establish whether they were complicated with IUGR or not. Our results showed that fetal upper arm volume assessed by 3D US can differentiate fetuses with IUGR from fetuses without IUGR well. The best predicting threshold for IUGR is at the 10th percentile by upper arm volume. Using the 10th percentile as the cutoff, the sensitivity of fetal upper arm volume in predicting IUGR was 97.5%, with specificity 92.8%, predictive value of positive test 54.9%, predictive value of negative test 99.8% and accuracy 93.1%. Furthermore, upper arm volume is the best parameter for detecting IUGR among the common fetal biometric indices, such as biparietal diameter (BPD), occipitofrontal diameter (OFD), head circumference (HC), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW). In conclusion, fetal upper arm volume assessed by quantitative 3D US can be used to predict fetuses with IUGR antenatally. We believe fetal upper arm volume assessment by 3D US would be a useful test in detecting fetuses with IUGR.

The efficacy assessment of thigh volume in predicting intrauterine fetal growth restriction by three-dimensional ultrasound

Intrauterine growth restriction (IUGR) is an important issue in perinatology. To assess the efficacy of fetal thigh volume (ThVol) in predicting IUGR, we undertook a prospective cross-sectional study using quantitative 3-D ultrasound (US). During the study period, 30 fetuses with IUGR and 282 fetuses with non-IUGR were included for the ThVol assessment in utero by 3-D US. All the fetuses were singletons and had follow-up to the delivery to determine whether they were complicated with IUGR or not. Our results showed fetal ThVol assessed by 3-D US can differentiate fetuses with IUGR from fetuses with non-IUGR well. Using the 10th percentile as the screening threshold, the sensitivity of fetal ThVol in predicting IUGR was 86.6%, with specificity 91.1%, predictive value of positive test 51.0%, predictive value of negative test 98.5% and accuracy 90.7%. In conclusion, fetal ThVol assessed by quantitative 3-D US can be used to predict fetuses with IUGR antenatally. We believe fetal ThVol assessment by 3-D US would be a useful test in detecting fetuses with IUGR.

Fetal growth and well-being

Accurate monitoring of fetal growth is one of the most critically important components of prenatal care. Whether too large or too small for gestational age, the ramifications of abnormal fetal growth have both short-term and long-term sequelae for early neonatal life and beyond. Although not perfectly accurate, ultrasound and other monitoring technologies have markedly improved the ability to follow abnormalities of fetal growth and to decide if early intervention or early delivery is necessary. Clearly, perinatal morbidity and mortality are decreased with close surveillance of these at-risk fetuses.

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.

Three-dimensional ultrasound experience in obstetrics

PURPOSE OF REVIEW

Three-dimensional (3D) ultrasound is a natural development of the imaging technology. Fast computers are essential to enable 3D and four-dimensional (4D) ultrasound pictures. A short review of the technical points and clinical aspects is presented. Our purpose is to acquaint the reader with the possibilities of this new technology and to increase awareness of its present clinical usefulness. A short review of technical information is provided.

RECENT FINDINGS

The advantages of 3D and 4D ultrasound in certain areas are unequivocal. Its use in the workup of fetal anomalies involving the face, limbs, thorax, spine and the central nervous system are already applied by most centers. The use of this technology in applying color Doppler, in guiding needles for different puncture procedures as well in evaluating the fetal heart are under close research scrutiny. The bonding effect between the parents and their future offspring is becoming evident as 3D ultrasound is used. Consulting specialists understand fetal pathology better and can better plan postnatal interventions. 4D or real time 3D ultrasound was developed and is expected to achieve new meaning with the planned introduction of electronic transducer multilinear arrays.

SUMMARY

3D ultrasound is an extremely promising imaging tool to image the fetus. In spite of the scant outcome studies the potential of 3D ultrasound is understood by a large number of obstetricians, maternal fetal specialists and imaging specialists.

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.

Fetal weight estimation by three-dimensional ultrasound

OBJECTIVE

To assess the value of three-dimensional volume scanning in predicting fetal weight at birth.

STUDY DESIGN

Prospective cross-sectional study within 7 days of delivery. A total of 190 patients were considered for final analysis (formula-finding group: n = 125, formula evaluation group: n = 65). Inclusion criteria were a singleton pregnancy and absence of chromosomal or significant structural anomalies. Three-dimensional (3D) volumetric measurements of the fetal thigh, upper arm and abdomen were performed together with conventional two-dimensional (2D) biometry.

RESULTS

All measurements were completed successfully in each patient. Polynomial regression analysis with standard biometric parameters and volumes of the upper arm, the thigh and the abdomen was employed to yield the best-fit formula for prediction of fetal weight at birth. The new 3D formula (estimated fetal weight (EFW) = -1478.557 + 7.242 x thigh volume + 13.309 x upper arm volume + 852.998 x log10 abdominal volume + 0.526 x BPD3) proved to be superior to established 2D equations with the lowest mean error (25.8 +/- 194.4 g), the lowest mean absolute error (155.2 +/- 118.2 g) and the lowest mean absolute percentage error (6.1 +/- 5.0%) when studied prospectively in the evaluation group.

CONCLUSION

3D sonography allows superior fetal weight estimation by including soft tissue volume. Further studies at the extremes of fetal weight are needed to confirm the value of our formula in these subsets.

An interactive tool to visualize three-dimensional ultrasound data

Three-dimensional ultrasound can provide images that are easily understood by people who are not specialists in ultrasonography. However, current visualization methods do not perform very well on 3-D ultrasound data. Apart from some specific cases (obstetrics, cardiology), 3-D ultrasound images have not yet demonstrated major benefits from a clinical point of view. In this article, we introduce an interactive method that allows the user easily to produce 3-D images for each ultrasound examination. It is a two-step method. First, the user roughly segments the data by drawing three boundary curves in perpendicular planes. A ray-casting algorithm then automatically retrieves the details of the objects. Because it can be used routinely, this tool should help to evaluate the potential of 3-D ultrasonography.

Three-dimensional ultrasound imaging

The objective of this article is to provide scientists, engineers and clinicians with an up-to-date overview on the current state of development in the area of three-dimensional ultrasound (3-DUS) and to serve as a reference for individuals who wish to learn more about 3-DUS imaging. The sections will review the state of the art with respect to 3-DUS imaging, methods of data acquisition, analysis and display approaches. Clinical sections summarize patient research study results to date with discussion of applications by organ system. The basic algorithms and approaches to visualization of 3-D and 4-D ultrasound data are reviewed, including issues related to interactivity and user interfaces. The implications of recent developments for future ultrasound imaging/visualization systems are considered. Ultimately, an improved understanding of ultrasound data offered by 3-DUS may make it easier for primary care physicians to understand complex patient anatomy. Tertiary care physicians specializing in ultrasound can further enhance the quality of patient care by using high-speed networks to review volume ultrasound data at specialization centers. Access to volume data and expertise at specialization centers affords more sophisticated analysis and review, further augmenting patient diagnosis and treatment.

Application of the surface rendering technique of three-dimensional ultrasound in prenatal diagnosis and counselling of Klippel-Trenaunay-Weber syndrome

Klippel Trenaunay-Weber syndrome is a complex developmental disorder characterized by a triad of cutaneous haemangioma, varicosities of the body, and unilateral limb hypertrophy. We describe the prenatal diagnosis of Klippel-Trenaunay-Weber syndrome at 15 weeks' gestation using the surface rendering technique of three-dimensional ultrasound. The vivid three-dimensional images of the affected fetus are invaluable in prenatal diagnosis and parental counselling.

Sonographic diagnosis of intrauterine growth restriction

Estimation of fetal weight in utero using multiple ultrasonic parameters remains the mainstay in screening for IUGR. The use of various fetal morphometric ratios and/or measurements of other fetal parameters may provide additional useful information. Serial evaluation to assess interval growth may be necessary to clarify the diagnosis. The use of Doppler ultrasound, especially the evaluation of the umbilical artery and middle cerebral artery velocity flow, is an important adjunct for both the diagnosis of IUGR caused by uteroplacental insufficiency and its continued management.

Predicting birth weight by fetal upper-arm volume with use of three-dimensional ultrasonography

OBJECTIVE

Our purpose was to determine the usefulness and accuracy of the three-dimensional ultrasonography assessed fetal upper-arm volume in predicting birth weight.

STUDY DESIGN

From June 1996 to October 1996, we performed a prospective study of ultrasonography on 105 pregnant women without fetal structural anomaly or aneuploidy. Both the traditional two-dimensional ultrasonographic parameters and three-dimensional ultrasonography for fetal upper arm volume were measured within 48 hours of delivery.

RESULTS

The upper arm volume correlated well with birth weight (r = 0.92, n = 105, p < 0.0001). With use of linear and polynomial regression, we obtained a best-fit new formula, Birth weight = 1088.60 + 36.024 x Upper-arm volume. The accuracy of this new formula is compared with that of two Chinese equations predicting fetal weight reported before and other formulas commonly used in the world as well. Our formula is more accurate in predicting birth weight than all the other formulas by traditional two-dimensional ultrasonography, either in error, percentage error, or absolute error. Another group by prospective validation further proved this finding.

CONCLUSION

The upper-arm volume assessed by three-dimensional ultrasonography can accurately predict birth weight, and its accuracy is superior to the previous, formulas. Our study has at least validated the application of upper-arm volume by three-dimensional ultrasonography in estimating fetal weight. Further larger series are needed to confirm our findings.

Control of intrauterine device insertion with three-dimensional ultrasound: is it the future?

A comparative study was designed to determine whether three-dimensional transvaginal sonography (3D-TVS) offered advantages over two-dimensional transvaginal sonography (2D-TVS) for the identification and location of IUDs in 66 asymptomatic women. Hysteroscopy was performed in cases in which there was a discrepancy between the information obtained by both methods (n = 14). In eight cases (12.2%) the IUD was misidentified with 2D-TVS. In six cases (9.1%) it was not possible to identify the device model with 2D-TVS. In two cases (3.0%) 2D-TVS failed to identify the position of the device. In contrast, all IUDs were identified and located accurately with 3D-TVS.