Effectiveness of fetal cardiac screening for congenital heart disease using a combination of the four-chamber view and three-vessel view during the second trimester scan

Diagnostic accuracy of ultrasound screening for fetal structural abnormalities during the first and second trimester of pregnancy in low-risk and unselected populations

BACKGROUND

Prenatal ultrasound is widely used to screen for structural anomalies before birth. While this is traditionally done in the second trimester, there is an increasing use of first-trimester ultrasound for early detection of lethal and certain severe structural anomalies.

OBJECTIVES

To evaluate the diagnostic accuracy of ultrasound in detecting fetal structural anomalies before 14 and 24 weeks' gestation in low-risk and unselected pregnant women and to compare the current two main prenatal screening approaches: a single second-trimester scan (single-stage screening) and a first- and second-trimester scan combined (two-stage screening) in terms of anomaly detection before 24 weeks' gestation.

SEARCH METHODS

We searched MEDLINE, EMBASE, Science Citation Index Expanded (Web of Science), Social Sciences Citation Index (Web of Science), Arts & Humanities Citation Index and Emerging Sources Citation Index (Web of Science) from 1 January 1997 to 22 July 2022. We limited our search to studies published after 1997 and excluded animal studies, reviews and case reports. No further restrictions were applied. We also screened reference lists and citing articles of each of the included studies.

SELECTION CRITERIA

Studies were eligible if they included low-risk or unselected pregnant women undergoing a first- and/or second-trimester fetal anomaly scan, conducted at 11 to 14 or 18 to 24 weeks' gestation, respectively. The reference standard was detection of anomalies at birth or postmortem.

DATA COLLECTION AND ANALYSIS

Two review authors independently undertook study selection, quality assessment (QUADAS-2), data extraction and evaluation of the certainty of evidence (GRADE approach). We used univariate random-effects logistic regression models for the meta-analysis of sensitivity and specificity.

MAIN RESULTS

Eighty-seven studies covering 7,057,859 fetuses (including 25,202 with structural anomalies) were included. No study was deemed low risk across all QUADAS-2 domains. Main methodological concerns included risk of bias in the reference standard domain and risk of partial verification. Applicability concerns were common in studies evaluating first-trimester scans and two-stage screening in terms of patient selection due to frequent recruitment from single tertiary centres without exclusion of referrals. We reported ultrasound accuracy for fetal structural anomalies overall, by severity, affected organ system and for 46 specific anomalies. Detection rates varied widely across categories, with the highest estimates of sensitivity for thoracic and abdominal wall anomalies and the lowest for gastrointestinal anomalies across all tests. The summary sensitivity of a first-trimester scan was 37.5% for detection of structural anomalies overall (95% confidence interval (CI) 31.1 to 44.3; low-certainty evidence) and 91.3% for lethal anomalies (95% CI 83.9 to 95.5; moderate-certainty evidence), with an overall specificity of 99.9% (95% CI 99.9 to 100; low-certainty evidence). Two-stage screening had a combined sensitivity of 83.8% (95% CI 74.7 to 90.1; low-certainty evidence), while single-stage screening had a sensitivity of 50.5% (95% CI 38.5 to 62.4; very low-certainty evidence). The specificity of two-stage screening was 99.9% (95% CI 99.7 to 100; low-certainty evidence) and for single-stage screening, it was 99.8% (95% CI 99.2 to 100; moderate-certainty evidence). Indirect comparisons suggested superiority of two-stage screening across all analyses regarding sensitivity, with no significant difference in specificity. However, the certainty of the evidence is very low due to the absence of direct comparisons.

AUTHORS' CONCLUSIONS

A first-trimester scan has the potential to detect lethal and certain severe anomalies with high accuracy before 14 weeks' gestation, despite its limited overall sensitivity. Conversely, two-stage screening shows high accuracy in detecting most fetal structural anomalies before 24 weeks' gestation with high sensitivity and specificity. In a hypothetical cohort of 100,000 fetuses, the first-trimester scan is expected to correctly identify 113 out of 124 fetuses with lethal anomalies (91.3%) and 665 out of 1776 fetuses with any anomaly (37.5%). However, 79 false-positive diagnoses are anticipated among 98,224 fetuses (0.08%). Two-stage screening is expected to correctly identify 1448 out of 1776 cases of structural anomalies overall (83.8%), with 118 false positives (0.1%). In contrast, single-stage screening is expected to correctly identify 896 out of 1776 cases before 24 weeks' gestation (50.5%), with 205 false-positive diagnoses (0.2%). This represents a difference of 592 fewer correct identifications and 88 more false positives compared to two-stage screening. However, it is crucial to acknowledge the uncertainty surrounding the additional benefits of two-stage versus single-stage screening, as there are no studies directly comparing them. Moreover, the evidence supporting the accuracy of first-trimester ultrasound and two-stage screening approaches primarily originates from studies conducted in single tertiary care facilities, which restricts the generalisability of the results of this meta-analysis to the broader population.

Improving the Quality of Fetal Heart Ultrasound Imaging With Multihead Enhanced Self-Attention and Contrastive Learning

Fetal congenital heart disease (FCHD) is a common, serious birth defect affecting ∼1% of newborns annually. Fetal echocardiography is the most effective and important technique for prenatal FCHD diagnosis. The prerequisites for accurate ultrasound FCHD diagnosis are accurate view recognition and high-quality diagnostic view extraction. However, these manual clinical procedures have drawbacks such as, varying technical capabilities and inefficiency. Therefore, the automatic identification of high-quality multiview fetal heart scan images is highly desirable to improve prenatal diagnosis efficiency and accuracy of FCHD. Here, we present a framework for multiview fetal heart ultrasound image recognition and quality assessment that comprises two parts: a multiview classification and localization network (MCLN) and an improved contrastive learning network (ICLN). In the MCLN, a multihead enhanced self-attention mechanism is applied to construct the classification network and identify six accurate and interpretable views of the fetal heart. In the ICLN, anatomical structure standardization and image clarity are considered. With contrastive learning, the absolute loss, feature relative loss and predicted value relative loss are combined to achieve favorable quality assessment results. Experiments show that the MCLN outperforms other state-of-the-art networks by 1.52-13.61% when determining the F1 score in six standard view recognition tasks, and the ICLN is comparable to the performance of expert cardiologists in the quality assessment of fetal heart ultrasound images, reaching 97% on a test set within 2 points for the four-chamber view task. Thus, our architecture offers great potential in helping cardiologists improve quality control for fetal echocardiographic images in clinical practice.

Semi-Automatic Measurement of Fetal Cardiac Axis in Fetuses with Congenital Heart Disease (CHD) with Fetal Intelligent Navigation Echocardiography (FINE)

Congenital heart disease (CHD) is one of the most common organ-specific birth defects and a major cause of infant morbidity and mortality. Despite ultrasound screening guidelines, the detection rate of CHD is limited. Fetal intelligent navigation echocardiography (FINE) has been introduced to extract reference planes and cardiac axis from cardiac spatiotemporal image correlation (STIC) volume datasets. This study analyses the cardiac axis in fetuses affected by CHD/thoracic masses (n = 545) compared to healthy fetuses (n = 1543) generated by FINE. After marking seven anatomical structures, the FINE software generated semi-automatically nine echocardiography standard planes and calculated the cardiac axis. Our study reveals that depending on the type of CHD, the cardiac axis varies. In approximately 86% (471 of 542 volumes) of our pathological cases, an abnormal cardiac axis (normal median = 40-45°) was detectable. Significant differences between the fetal axis of the normal heart versus CHD were detected in HLHS, pulmonary atresia, TOF (p-value < 0.0001), RAA, situs ambiguus (p-value = 0.0001-0.001) and absent pulmonary valve syndrome, DORV, thoracic masses (p-value = 0.001-0.01). This analysis confirms that in fetuses with CHD, the cardiac axis can significantly deviate from the normal range. FINE appears to be a valuable tool to identify cardiac defects.

Improved Multi-Head Self-Attention Classification Network for Multi-View Fetal Echocardiography Recognition

The accurate acquisition of multiview fetal cardiac ultrasound images is very important for the diagnosis of fetal congenital heart disease (FCHD). However, these manual clinical procedures have drawbacks, e.g., varying technical capabilities and inefficiency. Therefore, exploring automatic recognition method for multiview images of fetal heart ultrasound scans is highly desirable to improve prenatal diagnosis efficiency and accuracy. In this work, we propose an improved multi-head self-attention mechanism called IMSA combined with residual networks to stably solve the problem of multiview identification and anatomical structure localization. In details, IMSA can capture short- and long-range dependencies from different subspaces and merge them to extract more precise features, thus making use of the correlation between fetal heart structures to make view recognition more focused on anatomical structures rather than disturbing regions, such as artifacts and speckle noises. We validate our proposed method on fetal cardiac ultrasound imaging datasets from a single center and 38 multicenter studies and the results outperform other state-of-the-art networks by 3%-15% of F1 scores in fetal heart six standard view recognition.Clinical Relevance- This technology has great potential in assisting cardiologists to complete the automatic acquisition of multi-section fetal echocardiography images.

The role of fetal echocardiogram after detection of extracardiac anomalies in utero (fetal echocardiogram for extracardiac malformations)

OBJECTIVE

We aimed to investigate the utility of comprehensive screening fetal echocardiography (FE) for patients diagnosed with any type of fetal extracardiac malformation (ECM) at a single multidisciplinary fetal center.

METHODS

We retrospectively reviewed all patients presenting to our referral center for FE due to a prenatal diagnosis of ECM (January 2013-December 2018).

RESULTS

Among 641 patients with ≥1 ECM referred for FE, 78 (12.2%) had CHD diagnosed at 25.6 ± 0.5 weeks. The frequency of CHD by type of ECM ranged from 35.1% for craniofacial to 9.8% for thoracic. Increasing number of fetal ECMs was strongly associated with CHD: odds ratio 2.01 (95% confidence interval: 1.06-3.69) for two ECMs, 9.57 (2.00-49.05) for three ECMs, and 11.68 (3.84-37.15) for more than three ECMs. Of fetuses with ECM and an abnormal genetic finding, 33.3% had CHD as compared to 10.9% of those without (p < 0.0001). Obstetric anatomy sonogram detected 43.6% of CHD.

CONCLUSION

CHD was commonly diagnosed among fetuses with any type of ECM at our center but was not always detected on obstetric sonogram. As the presence of CHD may impact decision-making and perinatal care, patients with a diagnosis of any fetal ECM should be considered for FE.

Reliability of Sonography-based Volume Computer Aided Diagnosis in the Normal Fetal Heart

OBJECTIVES

To explore the inter- and intra-observer reliability of Sonography-based Volume Computer Aided Diagnosis (SonoVCAD) in the display of 8 diagnostic planes of fetal echocardiography and to evaluate its efficiency.

METHODS

Three-dimensional volume data sets of the 56 normal singleton fetuses were acquired from a 4-chamber view by using a volume probe. After processing the data sets by using SonoVCAD, 8 cardiac diagnostic planes were displayed automatically. Three doctors with different experiences of performing fetal echocardiography evaluated each diagnostic plane and the success rates of 8 diagnostic planes were calculated. Inter-observer and intra-observer reliabilities were estimated by Cohen's kappa statistics.

RESULTS

A total of 276 volume data sets acquired from the 56 normal fetuses were used for SonoVCAD analysis and display. The success rate of each diagnostic section was more than 90%, ranging from 90.6% to 99.6%. Among 276 volumes, 81.5% (225/276) of volumes were able to generate all 8 diagnostic views successfully. Moderate to substantial agreement (kappa, 0.509-0.794) was found between 2 less experienced operators. Moderate to near-perfect agreement (kappa, 0.439-0.933) was found between an expert and 2 less experienced sonographers. Intra-observer reliability was substantial to near-perfect (kappa, 0.602-0.903). The efficiency of SonoVCAD was assessed. The expert spent less time than 2 less experienced examiners (P < 0.001) but no significant difference was found between 2 less experienced examiners (P = 0.176). Besides, SonoVCAD consumed significantly less time than 2-dimensional ultrasound (P < 0.001).

CONCLUSIONS

SonoVCAD can significantly improve the success rates of 8 diagnostic planes in fetal echocardiography with low operator dependency, good reproducibility and high efficiency.

WITHDRAWN: Effect of maternal rubella virus infection on fetal cardiac function and neural development by color doppler ultrasound (cardiography) information technology

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Why are congenital heart defects being missed?

OBJECTIVE

Congenital heart defects (CHD) are still missed frequently in prenatal screening programs, which can result in severe morbidity or even death. The aim of this study was to evaluate the quality of fetal heart images, obtained during the second-trimester standard anomaly scan (SAS) in cases of CHD, to explore factors associated with a missed prenatal diagnosis.

METHODS

In this case-control study, all cases of a fetus born with isolated severe CHD in the Northwestern region of The Netherlands, between 2015 and 2016, were extracted from the PRECOR registry. Severe CHD was defined as need for surgical repair in the first year postpartum. Each cardiac view (four-chamber view (4CV), three-vessel (3V) view and left and right ventricular outflow tract (LVOT, RVOT) views) obtained during the SAS was scored for technical correctness on a scale of 0 to 5 by two fetal echocardiography experts, blinded to the diagnosis of CHD and whether it was detected prenatally. Quality parameters of the cardiac examination were compared between cases in which CHD was detected and those in which it was missed on the SAS. Regression analysis was used to assess the association of sonographer experience and of screening-center experience with the cardiac examination quality score.

RESULTS

A total of 114 cases of isolated severe CHD at birth were analyzed, of which 58 (50.9%) were missed and 56 (49.1%) were detected on the SAS. The defects comprised transposition of the great arteries (17%), aortic coarctation (16%), tetralogy of Fallot (10%), atrioventricular septal defect (6%), aortic valve stenosis (5%), ventricular septal defect (18%) and other defects (28%). No differences were found in fetal position, obstetric history, maternal age or body mass index (BMI) or gestational age at examination between missed and detected cases. Ninety-two cases had available cardiac images from the SAS. Compared with the detected group, the missed group had significantly lower cardiac examination quality scores (adequate score (≥ 12) in 32% vs 64%; P = 0.002), rate of proper use of magnification (58% vs 84%; P = 0.01) and quality scores for each individual cardiac plane (4CV (2.7 vs 3.9; P < 0.001), 3V view (3.0 vs 3.8; P = 0.02), LVOT view (1.9 vs 3.3; P < 0.001) and RVOT view (1.9 vs 3.3; P < 0.001)). In 49% of missed cases, the lack of detection was due to poor adaptational skills resulting in inadequate images in which the CHD was not clearly visible; in 31%, the images showed an abnormality (mainly septal defects and aortic arch anomalies) which had not been recognized at the time of the scan; and, in 20%, the cardiac planes had been obtained properly but showed normal anatomy. Multivariate regression analysis showed that the volume of SAS performed per year by each sonographer was associated significantly with quality score of the cardiac examination.

CONCLUSIONS

A lack of adaptational skills when performing the SAS, as opposed to circumstantial factors such as BMI or fetal position, appears to play an important role in failure to detect CHD prenatally. The quality of the cardiac views was inadequate significantly more often in undetected compared with detected cases. Despite adequate quality of the images, CHD was not recognized in 31% of cases. A high volume of SAS performed by each sonographer in a large ultrasound center contributes significantly to prenatal detection. In 20% of undetected cases, CHD was not visible even though the quality of the images was good. © 2019 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Novel foetal echocardiographic image processing software (5D Heart) improves the display of key diagnostic elements in foetal echocardiography

Background

To evaluate the clinical value of foetal intelligent navigation echocardiography (5D Heart) for the display of key diagnostic elements in basic sections.

Methods

3D volume datasets of 182 normal singleton foetuses were acquired with a four chamber view by using a volume probe. After processing the datasets by using 5D Heart, eight cardiac diagnostic planes were demonstrated, and the image qualities of the key diagnostic elements were graded by 3 doctors with different experiences in performing foetal echocardiography.

Results

A total of 231 volume datasets acquired from the 182 normal foetuses were used for 5D Heart analysis and display. The success rate of 8 standard diagnostic views was 88.2%, and the success rate of each diagnostic view was 55.8–99.2% and 70.7–99.0% for the random four chamber view as the initial section and for the apical four chamber view as the initial section, respectively. The success rate of each diagnostic element in the 8 diagnostic sections obtained by 5D Heart was 58.9%~ 100%. Excellent agreement was found between experienced sonographers and less-experienced sonographers (kappa> 0.769). Inter- and intra-observer agreement were substantial to near-perfect, kappa values ranging from 0.612 to 1.000 (Cohen’s kappa).

Conclusions

5D Heart can significantly improve the image quality of key diagnostic elements in foetal echocardiography with low operator dependency and good reproducibility.

The Extended Fetal Cardiac Examination: Is It Feasible in a High-Risk Practice?

The aims of this study were to demonstrate the feasibility of obtaining additional cardiac views as proposed on an extended fetal cardiac examination and to see if there was any variation in individual components of that examination stratified by sonographer training, patient body habitus, or equipment. We retrospectively reviewed 200 consecutive detailed second-trimester high-risk fetal obstetric sonograms that included additional extended cardiac views. We analyzed the percentage of the time individual views were obtained, with variation based on (1) a sonographer with greater than 3 years of training compared with a group with 6 to 12 months of training, (2) 2 different ultrasound units, and (3) different body mass indices. Overall, the highest rate of visualization was achieved with the 4-chamber view (98.2%), whereas the 3-vessel tracheal view had the lowest percentage of visualization (40.2%), among the less experienced sonographers. Differences in successful completion of the extended cardiac views were not statistically different between the sonographer with a level of training greater than 3 years as compared with those with 6 to 12 months' training except for the 3-vessel tracheal view (P < 0.001). There is no statistically significant difference in our ultrasound equipment, when considering only inexperienced sonographers. Increasing body mass index had an inverse relationship with obtaining the components of the detailed cardiac examination. Using state-of-the-art ultrasound equipment and with focused additional training of obstetric sonographers, the majority of extended cardiac views can be obtained. There are exceptions.

Usefulness of color Doppler mode for fetal cardiac ultrasound screening in the second trimester: a study at a single perinatal center

Objectives: To evaluate the usefulness of color Doppler in fetal cardiac ultrasound screening in the second trimester.Methods: Fetuses who underwent ultrasound screening at 18-20 weeks' gestation at Showa University Hospital between 2011 and 2016 were evaluated. After delivery, neonatal congenital heart abnormalities were reviewed and compared with the antenatal ultrasound findings. Since 2014, we have added color Doppler to the routine B mode evaluation of the fetal heart. Congenital heart diseases (CHDs) found antenatally and postnatally were compared before and after protocol alternation. Medical records of all fetuses who underwent ultrasound screening at 18-20 weeks' gestation at Showa University Hospital between 2011 and 2016 were retrospectively reviewed.Results: There were 47 cases of CHDs confirmed postnatally. The detection rates of CHDs were 45.0% (9/20) in 2011-2013 and 55.6% (15/27) in 2014-2016. In 2011-2013, cases with antenatal diagnosis showed obvious abnormal findings of three-vessel view and four-chamber view with the B mode. In 2014-2016, the detection rate of isolated ventricular septal defect (VSD) was elevated from 10 to 42.9% using color Doppler.Conclusions: In this study, color Doppler improved the detection rate of CHDs. Color Doppler could give us additional information on blood flow although the canal or vessel is too small to detect morphological changes in the second trimester. It might be a useful tool for screening of CHDs with stenosis, regurgitation, and shunt that are difficult to detect by only the B mode in the second trimester.

Is echocardiography necessary for all single umbilical artery fetuses? A retrospective study in a selected Chinese population

AIM

Previous evidence on the relationship between single umbilical artery (SUA) and congenital heart disease (CHD) is controversial. We thus conducted a retrospective study to explore the potential risk factors associated with CHD in SUA fetuses, and verify if all these SUA fetuses should be referred for detail fetal echocardiography.

METHODS

We reviewed medical records of SUA fetuses referred to Xinhua Hospital for fetal echocardiography between September 2009 and February 2014. All the pregnancies were divided into two groups of CHD and non-CHD according to the results of fetal echocardiography. The maternal and fetal characteristics were compared via χ² test and Fishers' test. Furthermore, Poisson regression was used to analyze the risk factors associated with CHD in SUA pregnancies.

RESULTS

Nineteen CHD cases (12.5%) were detected among 152 SUA fetuses, all with abnormal cardiac views during obstetric screening ultrasound (P < 0.001). χ² test showed that abnormal cardiac screening findings, extracardiac abnormality and infection or threatened abortion during first trimester were significantly associated with prenatal detection of CHD (P < 0.001). Multivariable Poisson regression after adjustment found that SUA fetuses with extracardiac abnormality had 4.74 (95% confidence interval: 1.89, 11.90) times higher risk of CHD.

CONCLUSION

Incidence of CHD was higher in SUA cases, and CHD fetuses could be screened efficiently by abnormal cardiac screening during obstetric screening ultrasound. SUA fetuses with extracardiac abnormality and maternal risk factors have higher risk of CHD, and should be strongly recommended for fetal echocardiography. In contrast, SUA fetuses without above situations might only need routine obstetric follow-up.