Cardiac screening examination of the fetus: guidelines for performing the 'basic' and 'extended basic' cardiac scan

Recommendations for Prenatal Echocardiography: A Report from International Prenatal Cardiology Collaboration Group

International Prenatal Cardiology Collaboration Group (IPCCG) links specialists from prenatal cardiology all over the world. In this recommendation we would like to focus on the fetal/prenatal echocardiography official report. So far many recommendations focused mainly on technical aspects of the fetal heart examination.

Congenital heart defects in IVF/ICSI pregnancy: systematic review and meta-analysis

OBJECTIVE

There is no consensus in current practice guidelines on whether conception by in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) techniques is an indication for performing a fetal echocardiogram. The aim of the study was to assess whether congenital heart defects (CHD) occur more often in pregnancies conceived after IVF/ICSI as compared with those conceived spontaneously.

METHODS

A systematic search for studies was conducted of PubMed/MEDLINE, EMBASE and Scopus from inception to September 2017. The search included the following medical subject heading (MeSH) terms alone or in different combinations: 'IVF', 'IVF/ICSI', 'ART pregnancy', 'assisted conception', 'birth defect', 'congenital heart defects' and 'congenital malformation or abnormalities'. Studies comparing neonatal incidence of CHD in pregnancies conceived after IVF/ICSI and those conceived spontaneously were included. Studies reporting on other types of assisted reproductive technology (ART) or lacking information concerning termination of pregnancy were excluded. Chromosomal abnormalities were excluded in all analyzed studies. A meta-analysis of selected cohort studies was conducted to estimate the pooled odds ratio (OR) with 95% CI using a random-effects model. Statistical heterogeneity among the studies was evaluated with the I2 statistic and Q-test.

RESULTS

Forty-one studies were identified for review including six case-control and 35 cohort studies. Data of eight selected cohort studies were used for meta-analysis. A total of 25 856 children conceived from IVF/ICSI techniques and 287 995 children conceived spontaneously, involving both singleton and multiple gestations, were included in the analysis. Total CHD events were 337/25 856 (1.30%) and 1952/287 995 (0.68%) in the IVF/ICSI and spontaneous conception groups, respectively. The risk of CHD was significantly increased in the IVF/ICSI group as compared with the spontaneous conception group (pooled OR, 1.45; 95% CI, 1.20-1.76; P = 0.0001; I2  = 44%; P = 0.08). In the subgroup of singleton IVF pregnancies, a significant difference was also obtained (OR, 1.55; 95% CI, 1.21-1.99; P = 0.0005; I2  = 36%; P = 0.18) and also multiple confounding factors adjusted ORs showed statistical significance (pooled OR, 1.29; 95% CI, 1.03-1.60; P = 0.02; I2  = 0%; P = 0.43).

CONCLUSION

Fetuses conceived with IVF/ICSI methods are at an increased risk of developing CHD compared with those conceived spontaneously. However, this finding deserves further investigation due to heterogeneity of both ART procedures and cardiac defects. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Absent fetal nasal bone in the second trimester and risk of abnormal karyotype in a prescreened population of Chinese women

INTRODUCTION

The aim of this study was to evaluate the value of absent fetal nasal bone in the prediction of fetal chromosomal abnormalities, according to whether it was associated with other soft markers or structural abnormalities in a prescreened population of Chinese pregnant women.

MATERIAL AND METHODS

In this retrospective cohort study, women whose fetuses had absent nasal bone detected during the second trimester ultrasound scan were followed. Fetal karyotyping was performed and pregnancy outcomes were recorded. The association between absent fetal nasal bone with abnormal karyotype was evaluated according to whether soft markers or structural abnormalities were also observed.

RESULTS

Fetal nasal bone was assessed in 56 707 singleton pregnancies. After exclusion of unqualified cases, 71 (71/56 707, 0.13%) fetuses were included in the final analyses, of which 16 (16/71, 22.54%) were detected to have chromosomal abnormalities, including 12 cases of trisomy-21, three of trisomy-18, and one of micro-deletion (in 7q). Among the 42 cases with isolated absence of nasal bone, two had trisomy-21 and one had a micro-deletion. Absence of nasal bone in association with other structural abnormalities had a higher rate of abnormal karyotypes compared with isolated absence of nasal bone [83.33% (10/12) vs. 7.14% (3/42), Fisher's exact test χ²  = 25.620, p < 0.001].

CONCLUSION

Absent fetal nasal bone is a highly specific ultrasonographic soft marker that should be included in the routine second trimester ultrasound scan.

Systematic review and meta-analysis of the performance of second-trimester screening for prenatal detection of congenital heart defects

BACKGROUND

The prenatal detection rate of congenital heart defects (CHDs) is increasing, but reported rates vary.

OBJECTIVES

To determine the performance of the second-trimester anomaly scan to detect CHD.

SEARCH STRATEGY

PubMed and Embase were searched for relevant studies in any language from inception to February 3, 2017. The search terms included "prenatal diagnosis" or "pregnancy," "cardiovascular diseases" or "cardiac defects," "congenital," and "specificity," or "sensitivity," or "cohort study."

SELECTION CRITERIA

Cohort studies assessing the detection rate of CHD during population-based prenatal screening from 1995 were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Data were collected from identified studies; authors were approached for additional data when necessary. A review and meta-analysis were performed. When possible, separate analyses were undertaken for isolated CHD cases.

MAIN RESULTS

Meta-analysis of seven studies showed the pooled detection rate of CHD in unselected populations as 45.1% (95% confidence interval 33.5%-57.0%). However, the rate of detection of univentricular defects and heterotaxy was above 85%. Similar rates were found among cases of isolated CHD.

CONCLUSIONS

Prenatal detection showed a strong correlation with CHD severity. The detection of conotruncal anomalies needs to improve. A thoroughly organized screening program will be essential to achieve a higher detection rate.

Role of HDLive in Imaging the Fetal Heart

HDLive is a rendering methodology that generates realistic images of the human fetus from sonographic data. The objective of this study is to demonstrate the utility of high-definition live in evaluating fetal heart especially in the first trimester (11-14-week) scan. The normal atrioventricular valve and its abnormalities along with septal defects can be vividly demonstrated with this technique, and eight cases with cardiac defects are illustrated. Its use in the first-trimester evaluation of heart would give a better perspective of the cardiac malformation, which provides the opportunity for counseling options early in pregnancy.

Left ventricle segmentation in fetal echocardiography using a multi-texture active appearance model based on the steered Hermite transform

OBJECTIVE

Fetal echocardiographic analysis is essential for detecting cardiac defects at early gestational ages. Fetal cardiac function can be assessed by performing some measurements regarding the dimension and shape of the heart cavities. In this work we propose an automatic segmentation method applied to the analysis of the left ventricle in fetal echocardiography.

METHODS

For segmentation of the left ventricle, we designed a novel multi-texture active appearance model (AAM) based on the Hermite transform (HT). Local orientation analysis is addressed by steering the coefficients obtained with the HT. The method basically consists of an AAM-based scheme which uses the steered HT to efficiently code texture patterns of the input image. A wider and detailed description of the image features can be obtained with this method. Compared with classic AAM methods, the segmentation performance is substantially improved with the proposed scheme. Since AAM-based approaches process local information, an automatic method is also proposed to initialize the multi-texture AAM. For this purpose, a database of pre-segmented images was built. Then, techniques such as thresholding, mathematical morphology and correlation are combined to identify the position and orientation of the left ventricle. Typical issues found in fetal cardiac ultrasound images such as different orientations and shape variations of the heart cavities can be easily handled with the designed method.

RESULTS

Several images of fetal echocardiography were used to evaluate the proposed segmentation method. The algorithm performance was validated using different metrics. We used a database of 143 real images of fetal hearts acquired for different phases of the cardiac cycle. We obtained an average Dice coefficient of 0.8631 and a point-to-curve distance of 2.027 pixels. The proposed algorithm was also validated by comparing it with other segmentation methods.

CONCLUSIONS

We have designed an automatic algorithm for left ventricle segmentation in fetal echocardiography. The reported results demonstrate that the proposed approach can achieve an efficient segmentation of the left ventricular cavity. Typical problems found in images of fetal echocardiography are satisfactorily handled with the proposed multi-texture AAM scheme.

Azygos Vein Z Scores in Healthy Fetuses and Fetuses With Venous Malformations Related to the Azygos Vein

OBJECTIVES

To establish fetal azygos vein and descending aorta sonographic Z score formulas based on femur length and gestational age and to determine the value of azygos vein diameter variation for potential use in the diagnosis of fetal venous malformations related to the azygos vein.

METHODS

A total of 452 healthy singleton fetuses and 25 fetuses with venous malformations related to the azygos vein underwent prenatal sonography in this retrospective study. Azygos vein and descending aorta diameters were measured offline after spatiotemporal image correlation volume acquisition. Normal azygos vein and descending aorta Z score formulas were constructed for these measurements based on femur length by performing standard regression analysis followed by weighted regression of absolute residual values. The azygos vein-to-descending aorta ratio was calculated. Three parameters were compared between venous malformations related to the azygos vein and healthy fetuses.

RESULTS

Azygos vein and descending aorta Z score formulas were constructed. Both showed a positive linear correlation with femur length (r = 0.79 and 0.90, respectively; P < .01) and gestational age (r = 0.79 and 0.91; P < .01). The azygos vein Z scores and azygos vein-to-descending aorta ratios of fetuses with malformations were significantly higher than those of healthy fetuses (P < .01). In the abnormal group, 96.0% of azygos vein Z scores (24 of 25) were greater than ±2, and 96.0% of azygos vein-to-descending aorta ratios (24 of 25) were greater than the 95% confidence interval.

CONCLUSIONS

The azygos vein Z score formulas we developed can provide a quantitative basis for prenatal screening of venous malformations related to the azygos vein. Azygos vein dilatation and an abnormal azygos vein-to-descending aorta ratio may contribute to increasing the recognition of venous malformations involving the azygos vein.

Length to width ratio of the ductus venosus in simple screening for fetal congenital heart diseases in the second trimester

Antenatal diagnosis of congenital heart disease (CHD) is still low even though screening was first introduced over 25 years ago. The purpose of our study was to determine the efficacy of a second-trimester prenatal ultrasonographic method of screening for CHD.From September 2012 to September 2013, the length and width of the fetal ductus venosus were measured sonographically in 1006 singleton fetuses, and the ratio of length to width was calculated. The accuracy of each fetal measurement and Doppler ultrasonography were determined. The standard fetal echocardiographic evaluations including 2-dimensional gray-scale imaging, color, and Doppler color flow mapping were performed. The transducer was aligned to the long axis of the fetal trunk to view the ductus venosus in its full length, including the inlet (isthmus) and outlet portions of the vessel. The diameters of the vessel inner wall and mid-point of the ductus venosus were measured using calipers. All scans and fetal measurements were conducted by a registered sonographer with more than 20 years of perinatal ultrasound screening experience.Of the 1006 singleton fetuses between 19 and 28 weeks' gestation, 36 had CHD. The ductus venosus length/width ratio (DVR) for the first CHD screening was extremely sensitive at 88.90%, with a specificity of 99.10% for the cardiac abnormalities included in this study. Chromosomal anomalies accompanied CHD in 0.4% (4/1006) of all cases and 11.11% (4/36) of the CHD cases.The DVR differed significantly between fetuses with CHD and normal fetuses during the second trimester. Careful assessment of the ratio should be a part of the sonographic examination of every fetus. In the case of a small DVR, advanced echocardiography and karyotype analysis should be performed. The ratio is a helpful tool for screening CHD abnormalities prenatally in the Chinese population.

Assessment of the Fetal Heart During Routine Obstetrical Screening, a Standardized Method

Assessment of the fetal heart during routine obstetrical screening remains a challenge for sonographers and physicians. Reliance on still images and nonstandard methods of acquiring images and assessing the fetal heart contribute to the relatively low rate of identification of congenital heart disease (CHD). A standardized assessment of the fetal heart using two cine-loop sweeps has been shown to address some of these challenges. Image acquisition using two cine-loop sweeps combined with a standardized five-step assessment is proposed to address the limitations of the nonstandard approach in place at most screening centers today.

Severity of Fetal Brain Abnormalities in Congenital Heart Disease in Relation to the Main Expected Pattern of in utero Brain Blood Supply

Objectives: We evaluated the hypothesis that in fetuses with congenital heart disease (CHD) there is a correlation between the expected pattern of in utero brain blood supply and the severity of neurodevelopmental impairment. Methods: A total of 58 fetuses with CHD and 58 controls underwent a Doppler ultrasound and fetal MRI at 36-38 weeks. Fetuses with CHD were divided into two functional classes: class A with an expected severe reduction in oxygenated brain blood supply (left outflow tract obstruction and transposition of great vessels) and class B with theoretically near-normal or mildly impaired oxygenated brain blood supply (other CHD). Head biometry and cerebroplacental Doppler were assessed by ultrasound, and brain volumetry, cortical development and metabolism by MRI. Results: Both class A and B CHD fetuses had significant differences in head biometry, brain perfusion, cortical development and brain metabolism compared with controls. However, there was a significant linear tendency for head biometry, cerebral Doppler, volumes, cortical sulcation and metabolic ratios across the three clinical groups, with signs of more severe brain alterations in type A CHD fetuses. Conclusions: All fetuses with CHD showed significant brain developmental changes, but differences were more pronounced in CHD associated with an expected severe reduction in oxygenated blood supply to the brain.

Variation in Prenatal Diagnosis of Congenital Heart Disease in Infants

BACKGROUND AND OBJECTIVE

Prenatal diagnosis allows improved perioperative outcomes for fetuses with certain forms of congenital heart disease (CHD). Variability in prenatal diagnosis has been demonstrated in other countries, leading to efforts to improve fetal imaging protocols and access to care, but has not been examined across the United States. The objective was to evaluate national variation in prenatal detection across geographic region and defect type in neonates and infants with CHD undergoing heart surgery.

METHODS

Cardiovascular operations performed in patients ≤6 months of age in the United States and included in the Society of Thoracic Surgeons Congenital Heart Surgery Database (2006-2012) were eligible for inclusion. Centers with >15% missing prenatal diagnosis data were excluded from the study. Prenatal diagnosis rates were compared across geographic location of residence and defect type using the χ(2) test.

RESULTS

Overall, the study included 31,374 patients from 91 Society of Thoracic Surgeons Congenital Heart Surgery Database participating centers across the United States. Prenatal detection occurred in 34% and increased every year, from 26% (2006) to 42% (2012). There was significant geographic variation in rates of prenatal diagnosis across states (range 11.8%-53.4%, P < .0001). Significant variability by defect type was also observed, with higher rates for lesions identifiable on 4-chamber view than for those requiring outflow tract visualization (57% vs 32%, P < .0001).

CONCLUSIONS

Rates of prenatal CHD detection in the United States remain low for patients undergoing surgical intervention, with significant variability between states and across defect type. Additional studies are needed to identify reasons for this variation and the potential impact on patient outcomes.

Accuracy of Fetal Echocardiography in the Differential Diagnosis between Truncus Arteriosus and Pulmonary Atresia with Ventricular Septal Defect

OBJECTIVES

To report on the accuracy of fetal echocardiography in the distinction between truncus arteriosus communis (CAT) and pulmonary atresia with ventricular septal defect (PA-VSD) and to describe the association with extracardiac and chromosomal anomalies.

METHODS

This was a retrospective study on 31 fetuses with a single arterial trunk overriding a VSD with a nonidentifiable right ventricle outflow tract with anterograde flow. Data on the type of cardiac defect, gestational age, characteristics of the arterial trunk valve, presence of additional vascular, chromosomal and extracardiac abnormalities and postnatal outcome were obtained. Misdiagnosed cases were reevaluated by four-dimensional spatiotemporal image correlation (4D-STIC) echocardiography.

RESULTS

The overall diagnostic accuracy was 81% and increased to 93.5% with 4D-STIC. Chromosomal and extracardiac anomalies were detected in 40 and 27%, respectively. In the PA-VSD group, patent ductus arteriosus and major aortopulmonary collateral arteries (MAPCAs) were present in 70 and 50% of the cases, respectively, coexisting in 1 of 5 cases. MAPCAs were significantly associated with a right aortic arch and with a 22q11 microdeletion in 50% of cases.

CONCLUSIONS

A prenatal distinction between CAT and PA-VSD can currently be achieved in most cases. MAPCAs should be actively searched for when PA-VSD is suspected, as they are associated with a higher risk of 22q11 microdeletion and potentially complicate postnatal treatment.

Sonocubic fine: new three-dimensional ultrasound software to the screening of congenital heart diseases

Congenital heart disease is the most common fetal congenital malformations; however, the prenatal rate detection still is low. The two-dimensional echocardiography is the "gold standard" exam to screening and diagnosis of congenital heart disease during the prenatal; however, this exam is operator-depending and it is realized only in high risk pregnancies. Spatio-temporal image correlation is a three-dimensional ultrasound software that analyses the fetal heart and your connections in the multiplanar and rendering modes; however, spatio-temporal image correlation too is operator-depending and time-consuming. We presenting a new three-dimensional software named Sonocubic fine to the screening of congenital heart disease. This software applies intelligent navigation technology to spatio-temporal image correlation volume datasets to automatically generate nine fetal echocardiography standard views. Thus, this new software tends to be less operator-depending and time-consuming.

Prenatal ultrasonography and Doppler sonography for the clinical investigation of isolated ventricular septal defects in a late second-trimester population

BACKGROUND

The purpose of this study was to evaluate the efficacy of prenatal ultrasonography and Doppler sonography in detecting isolated ventricular septal defects (VSDs) in a late-second-trimester population.

METHODS

Fetal echocardiography, Doppler ultrasound, and biometry were used to evaluate 2,661 singleton fetuses (1,381 male fetuses and 1,280 female fetuses) between 1 August 2006 and 31 May 2010. The efficacy of each fetal biometry, Doppler ultrasound, and nasal bone length (NBL) measurement was evaluated in all of the fetuses. A standard fetal echocardiographic evaluation, including two-dimensional gray-scale imaging and color and Doppler color flow mapping, was performed on all fetuses.

RESULTS

We detected isolated VSDs in 124 of the 2,661 singleton fetuses between 19 and 24 weeks of gestation. The prevalence of isolated VSDs in the study population was 4.66%. A multiple logistic regression analysis indicated that short fetal NBL (odds ratio = 0.691, 95% confidence interval: 0.551 to 0.868) and the pulsatility index (PI) of the umbilical artery (odds ratio = 8.095, 95% confidence interval: 4.309 to 15.207) and of the middle cerebral artery (odds ratio = 0.254, 95% confidence interval: 0.120 to 0.538) are significantly associated with isolated VSDs.

CONCLUSION

Late-second-trimester fetal NBL, umbilical artery PI, and middle cerebral artery PI are useful parameters for detecting isolated VSDs, and can be used to estimate the a priori risk of VSDs in women at high risk and at low risk of isolated VSDs.

Prenatal detection of congenital heart diseases: one-year survey performing a screening protocol in a single reference center in Brazil

Objective. To describe the experience of a tertiary center in Brazil to which patients are referred whose fetuses are at increased risk for congenital heart diseases (CHDs). Methods. This was a cross-sectional observational study. The data was collected prospectively, during the year 2012, through a screening protocol of the fetal heart adapted from the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) guideline. We performed a fetal echocardiogram screening for all pregnant women who were referred to the fetal cardiology outpatient obstetrics clinic of a university hospital. The exams were classified as normal or abnormal. The cases considered abnormal were undergone to a postnatal echocardiogram. We categorized the abnormal fetal heart according to severity in “complex,” “significant,” “minor,” and “others.” Results. We performed 271 fetal heart screening. The incidence of abnormal screenings was 9.96% (27 fetuses). The structural CHD when categorized due to severity showed 48.1% (n = 13) of “complex” cases, 18.5% (n = 5) “significant” cases, and 7.4% (n = 2) “minor” cases. The most common referral reason was by maternal causes (67%) followed by fetal causes (33%). The main referral indication was maternal metabolic disease (30%), but there was just one fetus with CHD in such cases (1.2%). CHDs were found in 19/29 fetuses with suspicion of some cardiac abnormality by obstetrician (65.5%). Conclusion. We observed a high rate of CHD in our population. We also found that there was higher incidence of complex cases.

Timing of ultrasound in pregnancy--how often? At what intervals?

The second trimester fetal anatomic survey has continued to evolve over the past 27 years. This review will summarize the changes in the anatomic survey that have occurred and provide recommendations that serve to improve compliance with the components of the survey. In order to provide clarity and direction, the goals and limitations of the second trimester fetal anatomic survey should be defined. The visualization rate of specific fetal anatomic structures can be increased by specifying acceptable, alternative views. A single follow-up examination within 2-4 weeks of a fetal anatomic survey or before 22 weeks' gestation should be offered when specific components of the fetal anatomic survey cannot be visualized. The fetal anomalies that the anatomic survey seeks to identify should be defined along with an acceptable detection rate.

The effect of preliminary training on quantitative evaluation of sonographer performance in the fetal morphology ultrasound examination

Introduction: The aim of this study is to provide a quantitative scoring system to assess sonographer performance by reviewing images from the fetal morphology examination.

Methods: Ten ultrasound images from patients at 18–22 weeks gestation were assessed and scored for quality according to predefined criteria. One hundred normal cases were randomly selected and 10 images from each case were analysed by four experienced reviewers. The preliminary training incorporated the first 25 cases and involved a training period for reviewers; the remaining 75 cases were allocated to post training. The scores acquired by each reviewer were statistically analysed using Pearson's and intra‐class correlations to determine the reproducibility of the results.

Results: The preliminary training results were calculated separately and compared to the post training study. The preliminary intra‐class correlation coefficient was 0.12. In the post training study the intra‐class correlation coefficient was doubled at 0.24. The greatest correlation was observed between reviewers 1 and 4 with a coefficient of 0.71. Reviewers 3 and 4 demonstrated the lowest correlation coefficient of 0.30.

Discussion: A significant increase in the intra‐class correlation coefficient indicated that training reviewers achieves more reproducible results. Suggested improvements to the study include recording fetal position, maternal BMI and assessing individual reviewer variability. An instruction manual defining each criterion might also yield better results.

Conclusion: The quantitative method used in this study assessed ultrasound images by placing a numerical value on image quality. Analysis of the preliminary training period demonstrates improved reproducibility of the results. Further investigation into the criteria is necessary to refine the quantitative method.

A pictorial guide for the second trimester ultrasound

Introduction: The second trimester ultrasound remains an important screening tool for detecting fetal abnormalities. This pictorial guide for the second trimester ultrasound is designed to assist practitioners to produce a high quality diagnostic survey of the fetus by demonstrating and describing recommended images. Methods: Each image is discussed in detail and has an associated drawn line diagram to aid in the identification of the important features of that image. There is a description of the salient landmarks and relevant measurements. Result: The authors hope this article may act as a useful guide to all practitioners performing second trimester ultrasounds.

Translational paradigms in scientific and clinical imaging of cardiac development

Congenital heart defects (CHD) are the most prevalent congenital disease, with 45% of deaths resulting from a congenital defect due to a cardiac malformation. Clinically significant CHD permit survival upon birth, but may become immediately life threatening. Advances in surgical intervention have significantly reduced perinatal mortality, but the outcome for many malformations is bleak. Furthermore, patients living while tolerating a CHD often acquire additional complications due to the long-term systemic blood flow changes caused by even subtle anatomical abnormalities. Accurate diagnosis of defects during fetal development is critical for interventional planning and improving patient outcomes. Advances in quantitative, multidimensional imaging are necessary to uncover the basic scientific and clinically relevant morphogenetic changes and associated hemodynamic consequences influencing normal and abnormal heart development. Ultrasound is the most widely used clinical imaging technology for assessing fetal cardiac development. Ultrasound-based fetal assessment modalities include motion mode (M-mode), two dimensional (2D), and 3D/4D imaging. These datasets can be combined with computational fluid dynamics analysis to yield quantitative, volumetric, and physiological data. Additional imaging modalities, however, are available to study basic mechanisms of cardiogenesis, including optical coherence tomography, microcomputed tomography, and magnetic resonance imaging. Each imaging technology has its advantages and disadvantages regarding resolution, depth of penetration, soft tissue contrast considerations, and cost. In this review, we analyze the current clinical and scientific imaging technologies, research studies utilizing them, and appropriate animal models reflecting clinically relevant cardiogenesis and cardiac malformations. We conclude with discussing the translational impact and future opportunities for cardiovascular development imaging research.

Application of spatio-temporal image correlation technology in the diagnosis of fetal cardiac abnormalities

Congenital heart disease is the birth defect with the highest incidence in China. Its timely and accurate prenatal diagnosis is critical for appropriate perinatal and postnatal management and salvage treatment. With improvements in the diagnostic capabilities of ultrasound and clinical manipulation techniques, prenatal diagnosis is conducted increasingly early and with greater accuracy. However, the representations of tiny blood vessels and the determination of abnormal spatial structures in the fetal period continue to cause difficulties in prenatal diagnosis. In theory, spatio-temporal image correlation (STIC) technology is able to compensate for the defects of previous traditional two-dimensional (2D) ultrasound and improve the diagnostic accuracy. The aim of the present study was to investigate the clinical application value of STIC technology combined with traditional 2D ultrasound in the diagnosis of fetal cardiac abnormalities. A total of 1,286 fetuses were subjected to sequential echocardiographic examination, during which STIC technology was used to collect heart volume data and carry out image post-processing and off-line analysis. In addition, the prenatal and postnatal echocardiography results were compared with the pathology results following the induced labor of fetuses with cardiac abnormalities. The sensitivity, specificity, misdiagnosis rate and rate of missed diagnosis for the STIC technology in the diagnosis of prenatal fetal cardiac abnormalities were 97.4, 99.6, 0.4 and 2.6%, respectively. The total coincidence rate was 99.2% and the positive and negative predictive values were 97.9 and 99.4%, respectively; the statistics for the consistency check of the STIC technology in the diagnosis of fetal cardiac abnormalities are κ=0.991, P=0.000. STIC technology combined with fetal echocardiography may be used for the definite diagnosis of fetal heart malformations, with high sensitivity and specificity.

Rightward convexity of the great vessel arising from the anterior ventricle: a novel fetal marker for transposition of the great arteries

OBJECTIVES

Traditionally transposition of the great arteries (TGA) is suggested by bifurcation of the great vessel arising from the posterior ventricle and the parallel course of the great vessels as they leave the heart. These findings may be difficult to demonstrate, requiring additional fetal echocardiographic features to indicate TGA. In this study, we investigated a new marker of TGA, namely rightward convexity of the great vessel arising from the anterior ventricle.

METHODS

We reviewed fetal studies from 2006 to 2010 in which an antenatal diagnosis of TGA was confirmed postnatally. We specifically viewed images obtained by scanning the great vessel arising from the anterior ventricle cranially to the superior mediastinum at the level of the three vessels and trachea view and compared them with similar views in normal hearts.

RESULTS

In 21 cases of confirmed TGA, the great vessel arising from the anterior ventricle (aorta) coursing cranially demonstrated an abnormal convexity to the right. This was in contrast to convexity to the left or lack of convexity of the great vessel (pulmonary artery) arising from the anterior ventricle in fetuses with a normal heart. In two fetuses rightward vessel convexity from the anterior ventricle was the clue on the initial scan suggesting TGA, which was subsequently confirmed. In addition, only two vessels, the superior vena cava and aorta, were demonstrated in fetuses with TGA, the pulmonary artery and ductus arteriosus lying below (caudal to) the transverse arch.

CONCLUSIONS

Noting the rightward convexity of the great vessel arising from the anterior ventricle may aid in the prenatal diagnosis of TGA. Furthermore, the relative simplicity of this sign may make it valuable in fetal screening for this cardiac defect.

Fetal isolated prominent left brachiocepalic vein: in utero natural history and neonatal outcome

The objectives of this series were to describe the prenatal sonographic findings of a fetal isolated prominent left brachiocephalic vein with its in utero natural history and neonatal outcome and to discuss the differential diagnosis, especially with a total or partial anomalous pulmonary venous return malformation. We reviewed all cases referred to 2 tertiary medical centers with the presenting finding of a prominent, upper thorax transverse vein entering the superior vena cava. The primary suspicion of a subjective dilated left brachiocephalic vein, as a part of a supracardiac anomalous pulmonary venous return malformation, was investigated by a systematic anatomic evaluation. After exclusion of other cardiac and structural anomalies, we followed the pregnancies and their outcomes. Eight cases were recruited during a 7 year period. The mean maternal age was 31 years, and the mean gestational age at the time of diagnosis was 17 weeks. In 7 cases, the dilatation was not evident during 6 weeks of follow up. In 1 case, the dilatation was evident until delivery at 39 weeks and was not apparent on postnatal echocardiography or spiral computed tomography. All neonates developed without any heart or other complications. We conclude that after exclusion other malformations, a prominent left brachiocephalic vein is a benign transient phenomenon that does not persist post-partum in the neonate.

Accuracy, agreement, and reliability of fetal cardiac measurements using 4-dimensional spatiotemporal image correlation

OBJECTIVES

The purpose of this study was to evaluate the accuracy, agreement, and reliability of 4-dimensional sonography using spatiotemporal image correlation (STIC) in fetal cardiac measurements during the second and third trimesters.

METHODS

Four-dimensional cardiac STIC volumes were acquired from 150 low-risk singleton pregnancies at gestational ages of 18 to 38 weeks. A total of 11 dimensions of the fetal heart and great vessels were analyzed by two different observers. Accuracy was assessed by comparing the measurements acquired by 4-dimensional STIC with those determined by 2-dimensional echocardiography by calculating the mean error and mean percent error and depicted by Bland-Altman plots. Absolute agreement and reliability of STIC-based measurements were evaluated on the basis of an intraclass correlation coefficient (ICC).

RESULTS

For STIC-based measurements of cardiac dimensions, good accuracy was achieved by the two experienced observers (mean percent error, -3.10% to 0.87% for observer A; -2.49% to -0.33% for observer B), and absolute agreement was almost perfect (ICC, 95% confidence interval, 0.916-0.993 for observer A; 0.957-0.990 for observer B). Interobserver ICCs among the two observers were between 0.909 and 0.990 (95% confidence interval), whereas intraobserver ICCs for observer A were between 0.894 and 0.989, and those for observer B were between 0.893 and 0.985, showing no significant differences in the reliability of SITC with regard to observers.

CONCLUSIONS

Four-dimensional sonography with STIC is a feasible and accurate method for fetal cardiac dimension measurements in the second and third trimesters. It is in good agreement with 2-dimensional echocardiography and can be performed by different observers.

Routine use of color Doppler in fetal heart scanning in a low-risk population

Objectives. To investigate the detection rate of major fetal heart defects in a low-risk population implementing routine use of color Doppler. Material and Methods. In a prospective observational study, all women undergoing fetal heart scanning (including 6781 routine examinations in the second trimester) during a three-year period were included. First a gray-scale scanning was performed including assessment of the four-chamber view and the great vessels. Thereafter three cross-sectional planes through the fetal thorax were assessed with color Doppler. Results. Thirty-nine fetuses had major heart defects, and 26 (67%) were prenatally detected. In 9/26 (35%) of cases the main ultrasound finding was related to the use of color Doppler. The survival rate of live born children was 91%. Conclusions. Routine use of color Doppler in fetal heart scanning in a low-risk population may be helpful in the detection of major heart defects; however, still severe malformations were missed prenatally.

Observed prevalence of congenital heart defects from a surveillance study in China

OBJECTIVES

The purpose of this study was to estimate the prevalence of major and minor congenital heart defects among fetuses and neonates using sonography in a general population of 4 areas surrounding Shanghai, China.

METHODS

Pregnant women were recruited between April 2004 and December 2005 in Jiaxing City, Suzhou City, Changshu County, and Haining County. All participants could have 3 sonographic examinations performed by specially trained physicians regardless of medical indication: a fetal sonographic screen and fetal echocardiography between 20 and 28 weeks' gestation and neonatal echocardiography. Diagnoses of congenital heart defects were made on the basis of review of all available scans by an international group of experts in pediatric cardiology. Prevalence rates were calculated per 1000 births.

RESULTS

Among 4006 scanned fetuses and neonates, there were 75 congenital heart defects, including 12 major defects. The observed prevalence for all congenital heart defects was 18.7 (95% confidence interval, 14.8-23.5) per 1000 births, and the prevalence for major defects was 3.0 (95% confidence interval, 1.6-5.2) per 1000 births. The most common defects were ventricular septal defects (n = 47 [62.7%]), atrial septal defects (n = 14 [18.7%]), tetralogy of Fallot (n = 4 [5.3%]), and hypoplastic left heart syndrome (n = 3 [4.0%]).

CONCLUSIONS

The prevalence of all congenital heart defects in the 4 areas of China studied was higher than that reported in other countries, with ventricular septal defects being the most frequent defects. Our data likely reflect a better estimate of the total prevalence of congenital heart defects in China than reported previously.

Assessment of the fetal thymus by two- and three-dimensional ultrasound during normal human gestation and in fetuses with congenital heart defects

OBJECTIVES

Our objectives were to compare the size and volume of the developing fetal thymus obtained by two-dimensional ultrasound (2D-US) and three-dimensional ultrasound (3D-US), develop normative data for thymus volume (TV), and investigate TV in fetuses with congenital heart disease (CHD) and normal twin gestations.

METHODS

We studied 321 fetuses (gestational age (GA): 17-39 weeks) including 238 normal singletons, 64 normal twins and 19 singleton fetuses with CHD. We used 2D-US to assess fetal thymus maximum transverse diameter (MTD), maximum transverse area (MTA), anteroposterior diameter (APD) and superoinferior diameter (SID). TV was obtained by 3D-US using virtual organ computer-aided analysis. Measurements were adjusted for estimated fetal weight where appropriate. Linear regression analysis, general linear models and Fisher's Z-transformation were used where appropriate. A nomogram of fetal TV based on singleton gestations was produced according to previously published methods.

RESULTS

Ultrasound assessment of the fetal thymus was possible in 95.3% (306/321) of cases. Both 3D-US and 2D-US measurements were significantly correlated with GA (TV r = 0.989; MTA r = 0.918; MTD r = 0.884; APD r = 0.849; and SID r = 0.816; all P < 0.05). After Fisher's Z-transformation, the correlation between the TV and GA was significantly stronger than that between any individual 2D-US measurement and GA (P < 0.05). Normal twin fetuses had TVs similar to those of singletons adjusted for estimated fetal weight and GA (P = 0.85). TV adjusted for estimated fetal weight and GA was significantly lower in fetuses with CHD than in normal singletons (P < 0.05).

CONCLUSION

2D-US and 3D-US are useful tools for evaluation of the size and volume of the human fetal thymus through gestation. Fetal TV by 3D-US seems to reflect normal development of the thymus in utero better than do 2D-US measurements. Lower TV should be expected in association with CHDs.

Four-chamber view and 'swing technique' (FAST) echo: a novel and simple algorithm to visualize standard fetal echocardiographic planes

OBJECTIVE

To describe a novel and simple algorithm (four-chamber view and 'swing technique' (FAST) echo) for visualization of standard diagnostic planes of fetal echocardiography from dataset volumes obtained with spatiotemporal image correlation (STIC) and applying a new display technology (OmniView).

METHODS

We developed an algorithm to image standard fetal echocardiographic planes by drawing four dissecting lines through the longitudinal view of the ductal arch contained in a STIC volume dataset. Three of the lines are locked to provide simultaneous visualization of targeted planes, and the fourth line (unlocked) 'swings' through the ductal arch image (swing technique), providing an infinite number of cardiac planes in sequence. Each line generates the following plane(s): (a) Line 1: three-vessels and trachea view; (b) Line 2: five-chamber view and long-axis view of the aorta (obtained by rotation of the five-chamber view on the y-axis); (c) Line 3: four-chamber view; and (d) 'swing line': three-vessels and trachea view, five-chamber view and/or long-axis view of the aorta, four-chamber view and stomach. The algorithm was then tested in 50 normal hearts in fetuses at 15.3-40 weeks' gestation and visualization rates for cardiac diagnostic planes were calculated. To determine whether the algorithm could identify planes that departed from the normal images, we tested the algorithm in five cases with proven congenital heart defects.

RESULTS

In normal cases, the FAST echo algorithm (three locked lines and rotation of the five-chamber view on the y-axis) was able to generate the intended planes (longitudinal view of the ductal arch, pulmonary artery, three-vessels and trachea view, five-chamber view, long-axis view of the aorta, four-chamber view) individually in 100% of cases (except for the three-vessels and trachea view, which was seen in 98% (49/50)) and simultaneously in 98% (49/50). The swing technique was able to generate the three-vessels and trachea view, five-chamber view and/or long-axis view of the aorta, four-chamber view and stomach in 100% of normal cases. In the abnormal cases, the FAST echo algorithm demonstrated the cardiac defects and displayed views that deviated from what was expected from the examination of normal hearts. The swing technique was useful for demonstrating the specific diagnosis due to visualization of an infinite number of cardiac planes in sequence.

CONCLUSIONS

This novel and simple algorithm can be used to visualize standard fetal echocardiographic planes in normal fetal hearts. The FAST echo algorithm may simplify examination of the fetal heart and could reduce operator dependency. Using this algorithm, inability to obtain expected views or the appearance of abnormal views in the generated planes should raise the index of suspicion for congenital heart disease.

Satisfactory rate of postprocessing visualization of standard fetal cardiac views from 4-dimensional cardiac volumes acquired during routine ultrasound practice by experienced sonographers in peripheral centers

The aim of this study was to evaluate the feasibility of visualizing standard cardiac views from 4-dimensional (4D) cardiac volumes obtained at ultrasound facilities with no specific experience in fetal echocardiography. Five sonographers prospectively recorded 4D cardiac volumes starting from the 4-chamber view on 500 consecutive pregnancies at 19 to 24 weeks' gestation undergoing routine ultrasound examinations (100 pregnancies for each sonographer). Volumes were sent to the referral center, and 2 independent reviewers with experience in 4D fetal echocardiography assessed their quality in the display of the abdominal view, 4-chamber view, left and right ventricular outflow tracts, and 3-vessel and trachea view. Cardiac volumes were acquired in 474 of 500 pregnancies (94.8%). The 2 reviewers respectively acknowledged the presence of satisfactory images in 92.4% and 93.6% of abdominal views, 91.5% and 93.0% of 4-chamber views, in 85.0% and 86.2% of left ventricular outflow tracts, 83.9% and 84.5% of right ventricular outflow tracts, and 85.2% and 84.5% of 3-vessel and trachea views. The presence of a maternal body mass index of greater than 30 altered the probability of achieving satisfactory cardiac views, whereas previous maternal lower abdominal surgery did not affect the quality of reconstructed cardiac views. In conclusion, cardiac volumes acquired by 4D sonography in peripheral centers showed high enough quality to allow satisfactory diagnostic cardiac views.

Defining laterality of the descending thoracic aorta in a 4-chamber view of the heart

OBJECTIVE

Right descending aortas have been correlated with an increased risk of congenital heart disease. Nevertheless, the aortic position remains a largely overlooked diagnostic tool in second-trimester sonography because no formal system for assessing the position exists. By developing a method of assigning the position of the aorta relative to the thoracic midline, diagnostic use of the descending aorta's position might be implemented more easily.

METHODS

The method of assessing the position relative to the midline was tested by comparing the analysis of 2 independent observers, who showed a 94.4% concordance rate.

RESULTS

Comparison of the percentages of aortic positions between the gestational ages (GAs) of 18 and 21 weeks showed no significant correlation between the aortic position and GA.

CONCLUSIONS

We suggest simply paying attention to the aortic position in an already standard view. The extra effort is minimal, and it has the potential to improve the diagnostic accuracy of the 4-chamber view.

Three-dimensional fast acquisition with sonographically based volume computer-aided analysis for imaging of the fetal heart at 18 to 22 weeks' gestation

OBJECTIVE

The purpose of this study was to determine how frequently cardiac images derived from 3-dimensional (3D) volume sets, acquired by fast acquisition and evaluated with sonographically based volume computer-aided analysis (sonoVCAD), were satisfactory for prenatal screening at 18 to 22 weeks' gestation.

METHODS

A prospective study of 100 women with singleton pregnancies was undertaken. Three fast acquisition 3D volume sets were obtained from each patient. Four reviewers independently evaluated the 4-chamber and 5 extracted VCAD views. Factors contributing to unsatisfactory screening were also evaluated.

RESULTS

The frequency with which adequate views for cardiac screening could be obtained varied widely; some single views, such as that of the stomach, were well seen frequently, whereas others, such as the ductal arch, were well seen significantly less frequently (P < .05). A satisfactory screening examination, defined as a visualized 4-chamber, left ventricular outflow tract, right ventricular outflow tract, and axial stomach view, was obtained for 43% to 65% of patients (dependent on reviewer). Logistic regression revealed that obesity (odds ratio, 3.0; 95% confidence interval, 1.7-5.0) and a fetus with the spine toward the maternal abdomen (odds ratio, 1.7; 95% confidence interval, 1.1-2.5) were independently associated with an unsatisfactory screening examination

CONCLUSIONS

Three-dimensional fast acquisition volumes evaluated with sonoVCAD did not allow a satisfactory fetal cardiac screening examination to be obtained a high percentage of the time in a general obstetric population during the second trimester. Certain patient factors, such as body habitus and fetal position, are associated with unsatisfactory 3D imaging.

Satisfactory visualization rates of standard cardiac views at 18 to 22 weeks' gestation using spatiotemporal image correlation

OBJECTIVE

The purpose of this study was to determine the frequency with which 3 standard screening views of the fetal heart (4-chamber, left ventricular outflow tract [LVOT], and right ventricular outflow tract [RVOT]) can be obtained satisfactorily with the spatiotemporal image correlation (STIC) technique.

METHODS

A prospective study of 111 patients undergoing anatomic surveys at 18 to 22 weeks was performed. Two ultrasound machines with fetal cardiac settings were used. The best volume set that could be obtained from each patient during a 45-minute examination was graded by 2 sonologists with regard to whether the 4-chamber, LVOT, and RVOT images were satisfactory for screening.

RESULTS

All 3 views were judged satisfactory for screening in most patients: 1 sonologist graded the views as satisfactory in 70% of the patients, whereas the other found the views to be satisfactory in 83%. The position of the placenta did not alter the probability of achieving a satisfactory view, but a fetus in the spine anterior position was associated with a significantly lower probability that the views were regarded as satisfactory for screening (odds ratio, 0.28; 95% confidence interval, 0.09-0.70; P < .05).

CONCLUSIONS

This study suggests that STIC may assist with screening for cardiac anomalies at 18 to 22 weeks' gestation.

Prenatal screening for major congenital heart disease: superiority of outflow tracts over the 4-chamber view

OBJECTIVE

The purpose of this study was to determine the relative importance of the 4-chamber view (4CV) compared with the outflow tract views (OFTVs) in prenatal screening for major congenital heart disease (CHD).

METHODS

We prospectively evaluated 200 consecutive infants undergoing cardiac surgery at our institution for major CHD. By reviewing the infants' medical records and conducting bedside interviews with their parents or guardians, we evaluated detection rates both prenatally and postnatally (before and after discharge to home), and we noted any prenatally identifiable risk factors for CHD. For each infant, we determined whether the 4CV or OFTVs would be expected to have been normal or abnormal on routine midgestation screening fetal sonography.

RESULTS

A prenatal diagnosis of CHD was made in 65 infants (33%): 30 of 124 low-risk pregnancies (24%) and 35 of 76 high-risk pregnancies (46%). An abnormal screening midgestation 4CV would have been expected in up to 63% of the infants, whereas abnormal midgestation OFTVs would have been expected in up to 91% of the infants. Thus, the potential sensitivity for detecting major CHD was higher with the OFTVs than with the 4CV (91% versus 63%; P < .001). Moreover, the OFTVs were more sensitive than the 4CV for detecting ductal-dependent forms of CHD. Diagnosis after discharge to home occurred in 39 of 135 postnatal diagnoses (29%), including many cases of isolated outflow tract abnormalities requiring early invasive intervention.

CONCLUSIONS

Cases of major neonatal CHD with OFTV abnormalities predominate over cases with 4CV abnormalities, particularly among those forms of CHD requiring early invasive intervention.

Feasibility of automated 3-dimensional fetal cardiac screening in routine ultrasound practice

OBJECTIVE

The purpose of this study was to prospectively assess the clinical feasibility of an automated 3-dimensional (3D) software tool for extended basic cardiac screening in routine ultrasound practice.

METHODS

During the 2-month study period, all gravidas fitting our inclusion criteria were consecutively included. Cardiac 3D volumes were acquired within the time slot allocated for the usual 2-dimensional fetal examination. All volumes were assessed on their quality, based on display of the 4-chamber view, and on the ability to sufficiently display diagnostic cardiac planes (left ventricular outflow tract [LVOT], right ventricle outflow tract [RVOT], and stomach location) with Sonography-Based Volume Computer-Aided Diagnosis software (SonoVCAD; GE Healthcare, Milwaukee, WI).

RESULTS

Volume acquisition was successful in 107 of 126 cases (85%). For each sonographer, more than 70% of the acquired cardiac volumes were of high or sufficient quality. Separately analyzed, diagnostic planes of the LVOT, RVOT, and stomach location were visible in 62.1%, 81.6%, and 92.2%, respectively. An extended basic fetal cardiac examination based on retrieval of all diagnostic cardiac planes from a single volume using SonoVCAD could be performed in 46.6% of the cases.

CONCLUSIONS

This study shows that cardiac volume acquisition can be incorporated in a routine ultrasound screening program without much difficulty. However, currently, SonoVCAD software still lacks the consistency to be clinically feasible for cardiac screening purposes. Further advances in ultrasound technology and familiarization with 3D ultrasound might improve its performance.

Quality of 2- and 3-dimensional fast acquisition fetal cardiac imaging at 18 to 22 weeks: ramifications for screening

OBJECTIVE

The purpose of this study was to evaluate the frequency with which 6 different fetal cardiac views taken during a fetal ultrasound examination at 18 to 22 weeks' gestation can be obtained satisfactorily for cardiac anomaly screening using either a 2-dimensional (2D) static or 3-dimensional (3D) fast acquisition technique.

METHODS

A prospective study of 100 low-risk women undergoing an anatomic survey was performed. Standard static 2D and 3D fast acquisition volumes were obtained on all patients. The 2D and 3D images were assigned, in a random order, to be independently graded by 3 reviewers. The degree of inter-reviewer agreement was assessed through the use of the Cohen kappa statistic. The factors contributing to satisfactory imaging were evaluated by random effects logistic regression.

RESULTS

A significant proportion of both 2D and 3D images were judged unsatisfactory for screening purposes. However, 2D images were significantly more likely, for all cardiac views, to be judged satisfactory (P < .05). The odds ratios for the 2D technique's being more likely than the 3D technique to provide images satisfactory for screening were 2.6 for the 4-chamber view, 2.4 for the right ventricular outflow tract, 4 for the left ventricular outflow tract, 3.2 for the 3-vessel view, 8.6 for the aortic arch, and 2.2 for the ductal arch.

CONCLUSIONS

In this prospective study, static 2D imaging was significantly more likely than fast acquisition 2D imaging to yield cardiac views of high enough quality to satisfactorily screen for anomalies.

Impact of audit of routine second-trimester cardiac images using a novel image-scoring method

OBJECTIVE

To assess the impact of using an objective scoring method to audit cardiac images obtained as part of the routine 21-23-week anomaly scan.

METHODS

A prospective audit and re-audit (6 months later) were conducted on cardiac images obtained by sonographers during the routine anomaly scan. A new image-scoring method was devised based on expected features in the four-chamber and outflow tract views. For each patient, scores were awarded for documentation and quality of individual views. These were called 'Documentation Scores' and 'View Scores' and were added to give a 'Patient Score' which represented the quality of screening provided by the sonographer for that particular patient (maximum score, 15). In order to assess the overall performance of sonographers, an 'Audit Score' was calculated for each by averaging his or her Patient Scores. In addition, to assess each sonographer's performance in relation to particular aspects of the various views, each was given their own 'Sonographer View Scores', derived from image documentation and details of four-chamber view (magnification, valve offset and septum) and left and right outflow tract views. All images were scored by two reviewers, jointly in the primary audit and independently in the re-audit. The scores from primary and re-audit were compared to assess the impact of feedback from the primary audit.

RESULTS

Eight sonographers participated in the study. The median Audit Score increased significantly (P < 0.01), from 10.8 (range, 9.8-12.4) in the primary audit to 12.4 (range, 10.4-13.6) in the re-audit. Scores allocated by the two reviewers in the re-audit were not significantly different (P = 0.08).

CONCLUSION

Objective scoring of fetal heart images is feasible and has a positive impact on the quality of cardiac images acquired at the time of the routine anomaly scan. This audit tool has the potential to be applied in every obstetric scanning unit and may improve the effectiveness of screening for congenital heart defects.