The examiner's ultrasound experience has a significant impact on the detection rate of congenital heart defects at the second-trimester fetal examination

Errors in prenatal diagnosis

Prenatal screening and diagnosis are integral to antenatal care worldwide. Prospective parents are offered screening for common fetal chromosomal and structural congenital malformations. In most developed countries, prenatal screening is routinely offered in a package that includes ultrasound scan of the fetus and the assay in maternal blood of biochemical markers of aneuploidy. Mistakes can arise at any point of the care pathway for fetal screening and diagnosis, and may involve individual or corporate systemic or latent errors. Special clinical circumstances, such as maternal size, fetal position, and multiple pregnancy, contribute to the complexities of prenatal diagnosis and to the chance of error. Clinical interventions may lead to adverse outcomes not caused by operator error. In this review I discuss the scope of the errors in prenatal diagnosis, and highlight strategies for their prevention and diagnosis, as well as identify areas for further research and study to enhance patient safety.

Detection of the fetal conotruncal anomalies using real-time three-dimensional echocardiography with live xPlane imaging of the fetal ductal arch view

OBJECTIVE

To evaluate the role of live xPlane imaging of ductal arch view in detection of fetal conotruncal anomalies.

METHODS

Two hundred selected singleton pregnancies, including 152 normal cases, 27 conotruncal anomalies and 21 other types of fetal heart abnormalities were enrolled in this observational study. All the cases were scanned to visualize the ductal arch view with live xPlane imaging by a single observer. The detection rate of conotruncal and non-conotruncal anomalies with live xPlane imaging was compared.

RESULTS

In using this new method of live xPlane imaging, an abnormal ductal arch view was visualized in 92.6% of fetal conotruncal anomalies, compared with that of non-conotruncal anomalies (23.8%, p < 0.001).

CONCLUSION

The ductal arch view can be obtained by live xPlane imaging. This method is relatively simple and feasible, hence may be a useful tool to detect fetal conotruncal anomalies.

Improved prenatal detection of congenital heart disease in an integrated health care system

The reported prenatal detection rates (PDRs) for significant congenital heart disease (sCHD) have been suboptimal, even in the current era. Changes in prenatal ultrasound policy and training may lead to improved prenatal detection of sCHD. This study analyzed the results of a policy to assess fetal cardiac outflow tracts shown by screening prenatal ultrasound using the electronic medical record (EMR). During a 6-year period, fetuses and patients younger than 1 year with sCHD were identified. The EMR was used to gather detection and outcome data. As an internal control within the same health care system, the PDR of only the surgical cases was compared with that of a similar group in which documentation of the fetal cardiac outflow tracts was not standard policy. Among 25,666 births, sCHD was identified in 93 fetuses or patients, yielding an incidence of 3.6 per 1,000 births. The PDR was 74.1%. Detection after birth but before discharge was 20.4%, and detection after discharge was 5.4%. A significant improvement in the PDR of sCHD was found when a concerted effort was made to obtain fetal cardiac outflow tract views during pregnancy screening (59.3 vs. 28%). Within an integrated health care system and with the use of an EMR, a PDR of 74% can be obtained, and 94% of sCHD can be detected before discharge. A concerted program that includes documentation of fetal cardiac outflow tracts in the pregnancy screening can result in improved PDR of sCHD.

Can live xPlane imaging of the in-plane view of interventricular septum be used to detect fetal conotruncal anomalies?

OBJECTIVE

To evaluate the feasibility of live xPlane imaging visualizing the in-plane view of IVS in the screening of the fetal conotruncal anomalies.

METHOD

One hundred and fifty-two consecutive normal singleton fetuses and forty-eight fetal cardiac defects (27 conotruncal and 21 non-conotruncal cases), were enrolled in this study. The in-plane view of IVS was firstly acquired with live xPlane imaging and then judged whether it is normal or not by one operator. The focus was put on observing the relationship of pulmonary artery and aorta. The comparison between conotruncal and non-conotruncal anomalies in demonstrating the relationship of pulmonary artery and aorta was performed.

RESULT

There were 27 cases of conotruncal anomalies enrolled in this study and 19 cases (70.4%) had the abnormal relationship of aorta and pulmonary artery in the in-plane view of IVS. In 21 cases of non-conotruncal CHDs, however, there were only 5 cases (23.8%) had the abnormal relationship in the in-plane view of IVS (p < 0.001).

CONCLUSION

Live xPlane imaging of the in-plane view of IVS is feasible to detect the fetal conotruncal anomalies, which may potentially be a useful tool for the non-experienced operators to screen the fetal conotruncal anomalies.

Barriers to prenatal detection of congenital heart disease: a population-based study

OBJECTIVE

To evaluate the extent and determinants of missed prenatal detection of congenital heart disease (CHD) in a population-based setting.

METHODS

This was a retrospective cohort study of cases with CHD, excluding minor defects, identified between 1997 and 2007 by a statewide surveillance program. We examined a comprehensive list of potential risk factors for which data were available in the surveillance database from abstracted medical charts. We analyzed the association of fetal, maternal and encounter factors with 1) whether a prenatal ultrasound was performed and 2) prenatal detection of CHD.

RESULTS

CHD was detected prenatally in only 39% of 1474 cases, with no improvement in detection rate over the 10-year period. Among the 97% (n = 1431) of mothers who underwent one or more ultrasound examinations, 35% were interpreted as abnormal; fetal echocardiography was performed in 27% of the entire cohort. Maternal and encounter factors increasing the adjusted odds of prenatal detection included: family history of CHD (OR, 4.3 (95% CI, 1.9-9.9)), presence of extracardiac defects (OR, 2.7 (95% CI, 1.9-3.9)) and ultrasound location i.e. high risk clinic vs clinic (OR, 2.1 (95% CI, 1.3-3.1)). Defects that would be expected to have an abnormal outflow-tract view were missed more often (64%) than were those that would be expected to have an abnormal four-chamber view (42%).

CONCLUSION

The majority of CHD cases over the 10-year study period were missed prenatally and detection rates did not increase materially during that time. The failure to detect CHD prenatally was related to encounter characteristics, specifically involving screening ultrasound examinations, which may be targeted for improvement.

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.

Fetal cardiac screening and variation in prenatal detection rates of congenital heart disease: why bother with screening at all?

Antenatal screening for fetal cardiac abnormalities was introduced over 25 years ago, yet detection of congenital heart disease before birth remains a challenge. While experienced tertiary centers report a high level of diagnostic accuracy, with most major forms of congenital heart disease being detectable before birth, the overall detection rate remains low. Pregnancies at increased risk of having an affected baby are referred to tertiary centers for fetal ECG, but most cases of congenital heart disease will occur in low-risk pregnancies. These cases will only be detected by screening the low-risk population at the time of routine obstetric scanning. Many obstetric ultrasound units have learnt to successfully obtain, and correctly interpret, views of the heart, including the four-chamber view and outflow tract views. However, standards for doing this are not uniform, nationally or internationally, so there is a significant variation in detection rates across individual countries and between different countries. Early diagnosis of babies with lesions that can result in cardiovascular collapse and death, could improve their survival as well as reducing morbidity. In addition, detection of a cardiac abnormality during pregnancy allows time to prepare parents for the likely course of events after birth. It also facilitates detection of other abnormalities in the baby and gives parents a choice, even if the choice is difficult and unwelcome. As well as providing parents with accurate and up-to-date information regarding the their baby’s abnormality, it is vital to provide continuing support to help them deal with the problem, regardless of what decisions they make. Much work remains to establish a uniform standard for antenatal detection of cardiac abnormalities. More recent national guidelines for examining the fetal heart along with formalized auditing processes should help to achieve this, although considerable time and effort will be required, particularly with regard to the teaching and training required.

Interobserver agreement in detailed prenatal diagnosis of congenital heart disease by telemedicine using four-dimensional ultrasound with spatiotemporal image correlation

OBJECTIVE

To evaluate the clinical accuracy of four-dimensional (4D) echocardiography in the detailed prenatal diagnosis of congenital heart disease (CHD) in a telemedicine setting.

METHODS

Ten second-trimester spatiotemporal image correlation (STIC) volumes were sent to three observers in different tertiary care centers with expertise in 4D echocardiography. The 10 volumes were selected based on the type of diagnosis to cover a wide spectrum of CHD anomalies, and also included one normal fetal heart. Observers were asked to provide the diagnosis, the postprocessing modalities used and the time spent on examination, and to give a rating of the confidence for the diagnosis on a 5-point Likert scale. They were free to consult other colleagues, including pediatric cardiologists, but were blinded to the prenatal diagnosis and the neonatal outcome. A diagnostic scoring system was used to evaluate different aspects of the heart defects. The results were compared with neonatal echocardiography or postmortem findings ('gold standard').

RESULTS

In two cases all observers correctly diagnosed all details of the volume datasets. The observer with the best performance reached perfect agreement in six cases and nearly perfect agreement in three. The volumes were most frequently studied by sectional planes and were analyzed in a median time of 11.0 (range, 2.5-30.0) min. The median confidence score was 4.0 (range, 1.0-5.0).

CONCLUSIONS

In a telemedicine setting using STIC volumes, fetal cardiac anomalies can be diagnosed correctly by an expert. However, details required for adequate counseling and planning of postnatal care may be missed. STIC by telemedicine is a promising modality, although not accurate enough for exclusive use in clinical decision making regarding treatment, prognosis or termination of pregnancy.

Costs of prenatal detection of congenital heart disease

Little information is available about the transportation costs incurred from the missed prenatal diagnosis of congenital heart disease (CHD). The objectives of the present study were to analyze the costs of emergency transportation related to the postnatal diagnosis of major CHD and to perform a cost/benefit analysis of additional training for ultrasound technicians to study the implications of improved prenatal detection rates. The 1-year costs incurred for emergency transportation of pre- and postnatally diagnosed infants with CHD in Northern California and North Western Nevada were calculated and compared. The prenatal detection rate in our cohort (n = 147) was 30.6%. Infants postnatally diagnosed were 16.5 times more likely (p <0.001) to require emergency transport. The associated emergency transportation costs were US$542,143 in total for all patients with CHD. The mean cost per patient was $389.00 versus $5,143.51 for prenatally and postnatally diagnosed infants, respectively (p <0.001). Assuming an improvement in detection rates after 1-day training for ultrasound technicians, the investment in training cost can be recouped in 1 year if the detection rate increased by 2.4% to 33%. Savings of $6,543,476 would occur within 5 years if the detection rate increased to 50%. In conclusion, CHD diagnosed postnatally results in greater costs related to emergency transportation of ill infants. Improving the prenatal detection rates through improved ultrasound technician training could result in considerable cost savings.

Audit of 10 years of referrals for fetal echocardiography

OBJECTIVES

To evaluate trends over time, indications, diagnoses, noncardiac defects and outcome of fetuses referred for tertiary level echocardiography.

METHODS

Retrospective study of fetal echocardiograms performed between April 1999 and 2009.

RESULTS

Of the 623 fetuses included, 301 (48%) had cardiac pathology. Congenital heart defects (CHDs) were found in 243/301 (81%), mostly in the severe spectrum. Of the fetuses with CHDs, 26% (63/243) had chromosomal anomalies. The chromosomally normal fetuses with CHDs had a mortality rate of 43% (77/180) and 23% (41/180) had extra-cardiac anomalies. The termination of pregnancy (TOP) rate for all cardiac pathology was 24.9% (75/301) and for CHDs 29.6% (72/243). The TOP rates for CHDs diagnosed before 19 and 24 weeks gestation were 61% (28/46) and 44% (68/155), respectively. An increase in referrals followed the introduction of a national screening program, (nuchal translucency (NT) and routine structural ultrasound screening). The main referral indication was an increased NT (>95th percentile; 32% of cases). CHDs were found in 81/239 (34%) fetuses with an increased NT.

CONCLUSIONS

Referral indications for fetal echocardiography were appropriate (almost 50% had cardiac pathology). The mortality was high. Fetal outcome and TOP decisions correlated with CHD severity and presence of noncardiac defects. An increased NT is a strong marker for CHDs.

Online evaluation of fetal second-trimester four-chamber view images: a comparison of six evaluation methods

OBJECTIVE

To compare six online evaluation methods for auditing routine second-trimester four-chamber view still images.

METHODS

We evaluated three different scoring grids (subjective, five-item score and seven-item score), which were applied with or without access to online help, resulting in a total of six evaluation methods. For the subjective scoring grid, images were rated as excellent, good, fair, poor or very poor. For the five-item score, 1 point was allocated for visualization (vs non-visualization or non-evaluable) of each of: heart crux, atria, ventricles, apex and aorta, yielding a score of 0-5. For the seven-item score, 1 point was allocated for clear (vs unclear) visualization of each of: moderator band at the apex, interventricular septum, atrioventricular valves, non-linear insertion of atrioventricular valves (normal offset), septum primum, aorta and pulmonary vein. Each evaluation method was used via the Internet by three randomly selected reviewers, who evaluated the same set of 80 images. Reviewers were experienced in fetal ultrasound, but were not involved in the design of the study. Interrater agreement was the main outcome.

RESULTS

The five-item scoring grid with online help achieved the best interrater agreement (interrater intraclass correlation coefficient = 0.7).

CONCLUSIONS

Evaluation of the second-trimester sonographic four-chamber view is apparently best achieved with a simple five-item scoring grid.

Impact of fetal echocardiography

Prenatal diagnosis of congenital heart disease is now well established for a wide range of cardiac anomalies. Diagnosis of congenital heart disease during fetal life not only identifies the cardiac lesion but may also lead to detection of associated abnormalities. This information allows a detailed discussion of the prognosis with parents. For continuing pregnancies, appropriate preparation can be made to optimize the postnatal outcome. Reduced morbidity and mortality, following antenatal diagnosis, has been reported for coarctation of the aorta, hypoplastic left heart syndrome, and transposition of the great arteries. With regard to screening policy, most affected fetuses are in the “low risk” population, emphasizing the importance of appropriate training for those who undertake such obstetric anomaly scans. As a minimum, the four chamber view of the fetal heart should be incorporated into midtrimester anomaly scans, and where feasible, views of the outflow tracts should also be included, to increase the diagnostic yield. Newer screening techniques, such as measurement of nuchal translucency, may contribute to identification of fetuses at high risk for congenital heart disease and prompt referral for detailed cardiac assessment.

Scan the fetal heart by real-time three-dimensional echocardiography with live xPlane imaging

OBJECTIVE

To describe the methodology of live xPlane imaging in the visualization of the fetal heart in detail.

METHODS

Fifty-one consecutive pregnant women with singleton pregnancies were imaged to display four screening sections of the fetal heart, the four-chamber view, the left outflow tract view (LVOT), the right outflow tract view (RVOT), and the three-vessel and trachea view (3VT), using live xPlane imaging. The methodology of how to visualize the screening planes was described in detail. We used two methods to image the fetal heart with live xPlane imaging: one uses the four-chamber view as the starting plane and the other uses the longitudinal view of fetal upper thorax as the starting plane.

RESULTS

When using the four-chamber view as the starting plane, the visualization rate of LVOT, RVOT, and 3VT was 94.1% (48/51), 100% (51/51), and 98.0% (50/51), respectively. When using the longitudinal view as the starting plane, the visualization rate of four-chamber view, LVOT, RVOT, and 3VT was 100% (51/51), 100% (51/51), 41.2% (21/51), and 100% (51/51), respectively.

CONCLUSIONS

Live xPlane imaging can be used to visualize the screening views of the fetal heart, and potentially may be a useful tool for the assessment and diagnosis of fetal congenital heart diseases.

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.

Impact and issues of detecting fetal congenital heart defects in Kyushu, Japan

AIM

To determine the current status of fetal CHD screening in our region and to establish a CHD screening system in Japan.

MATERIAL AND METHODS

Subjects were 168 fetuses prenatally-diagnosed with CHD at four referral centers in Japan from 2003 to 2007. Subjects were divided into two groups: group A (n = 84) included cases without extracardiac sonographic abnormalities and known risk factors for CHD and group B (n = 84) included those with extracardiac sonographic abnormalities or risk factors. The diagnostics and outcomes between the groups were analyzed.

RESULTS

There were more cases of single ventricle and restrictive ductus arteriosus and fewer cases of ventricular septal defect and double outlet right ventricle in group A than in group B (P < 0.05). In group A, the most frequent referral reason was an abnormal four-chamber view. In group B, 37 cases had chromosomal anomalies. The mortality rates in group B were higher than those in group A (P < 0.05). There were no differences in mortality rates between fetuses without chromosomal anomalies in group B and group A.

CONCLUSION

Prenatally-diagnosed CHD were mostly limited to those cases with obvious abnormalities in the four-chamber view or those with chromosomal anomalies. Prenatal detection of CHD is useful for the prediction of outcomes.

Second trimester serum predictors of congenital heart defects in pregnancies without chromosomal or neural tube defects

OBJECTIVE

To compare euploid pregnancies with congenital heart defects (CHDs) to similar pregnancies without CHDs on typically collected second trimester biomarker measurements.

METHOD

Second trimester serum levels of alpha-fetoprotein (AFP), human chorionic gonadotrophin (hCG), and unconjugated estriol were compared for 306 CHD cases and 1224 no-CHD controls drawn from a sample of singleton pregnancies without chromosomal or neural tube defects (NTDs). Logistic regression models were built comparing biomarkers for cases and controls.

RESULTS

Regardless of the severity of defect, CHD cases were more likely to have unusually high AFP and/or hCG levels and/or unusually low hCG and/or uE3 levels [odds ratio (OR) 1.8-2.4, 95% confidence intervals (CIs) 1.2-4.0]. Cases with critical CHDs were more than twice as likely to have an AFP multiple of the median (MoM) ≥ the 95th percentile and/or an hCG and/uE3 MoM ≤ the 5th percentile (OR 2.1-3.9, 95% CIs 1.1-7.8).

CONCLUSION

Abnormal levels of specific second trimester maternal serum biomarkers indicated an increased risk for CHDs among this sample of low risk pregnancies. Our data suggest that future efforts aimed at improving CHD detection in low risk pregnancies may benefit from considering serum biomarkers.

Radiographer-acquired and radiologist-reviewed ultrasound examination--agreement with radiologist's bedside evaluation

BACKGROUND

Growing demand for ultrasound examinations and higher quality requirements motivate searching for routines combining the diagnostic accuracy of radiologist-performed examinations with the economical advantages of sonographer-performed examinations. One possible approach is to use strictly standardized acquisition and documentation schemes that give the radiologist access to all relevant information after the examination.

PURPOSE

To compare a recently introduced routine, combining acquisition by a radiographer, documentation as standardized cine-loops, and review by a radiologist ('standardized method'), with the formerly used routine where the diagnosis is made bedside by the radiologist ('traditional method').

MATERIAL AND METHODS

In 64 policlinic patients, the kidneys (n=27) or the gallbladder (n=37) were examined with both the standardized and the traditional method. The radiologists' findings of hydronephrosis, tumors, cysts, echogenicity changes, and cortical thickness (in the kidneys), and wall thickness, concrements, and polyps (in the gallbladder) were compared between the methods with respect to agreement (proportion of agreement and kappa coefficient) as well as systematic differences (McNemar's test).

RESULTS

The findings at the gallbladder examination showed a median agreement of 97% (86-100%; kappa=0.64-1.00), and those at the kidney examination, an agreement of 90% (78-100%; kappa=0.69-1.00). There were no significant systematic differences between the methods.

CONCLUSION

The satisfactory agreement in this preliminary study indicates that the new workflow with ultrasound examinations performed by a radiographer and analyzed off-line by a radiologist is promising, and motivates further studies.

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.

Potential role of maternal serum microRNAs as a biomarker for fetal congenital heart defects

Congenital heart defects (CHD) are the most common form of major birth defect, affecting almost 1% of live births. These defects place a significant economic burden on the National Health Service and on the psychological wellbeing of affected families. The early screening and identification of neonates with CHD could reduce morbidity and mortality by allowing proactive medical treatment and parental counseling about options during pregnancy, including termination. Fetal echocardiography is the principal screening tool for the identification of CHD, but its accuracy mainly depends on the skill and experience of the operator. Various biomarkers of screening for fetal CHD are currently available, such as nuchal translucency (NT), β-hCG and PAPP-A; however, these are non-specific indexes with high incidences of false positive results. Certain specific microRNAs (miRNAs) of cardiogenesis have been identified, which correlate positively with placental miRNA expression. These miRNAs of placental origin can be detected in maternal peripheral blood. Therefore, we postulate that these maternal serum miRNAs may be a potential biomarker for fetal CHD.

Collaborative study on 4-dimensional echocardiography for the diagnosis of fetal heart defects: the COFEHD study

OBJECTIVE

Congenital anomalies are the leading cause of infant mortality in the United States, and congenital heart defects (CHDs) are the most common type of birth defects. Recently, 4-dimensional ultrasonography (4DUS) with spatiotemporal image correlation (STIC) has been introduced for fetal echocardiography. Accumulating evidence indicates that 4DUS with STIC may facilitate the examination of the fetal heart. Our objectives were to determine the accuracy of 4DUS for the diagnosis of CHDs and the agreement among centers.

METHODS

This study included 7 centers with expertise in 4D fetal echocardiography. Fetuses with and without confirmed heart defects were scanned between 18 and 26 weeks, and their volume data sets were uploaded onto a centralized file transfer protocol server. Intercenter agreement was determined using a κ statistic for multiple raters.

RESULTS

Ninety volume data sets were randomly selected for blinded analysis. Overall, the median (range) sensitivity, specificity, positive and negative predictive values, and false-positive and -negative rates for the identification of fetuses with CHDs were 93% (77%-100%), 96% (84%-100%), 96% (83%-100%), 93% (79%-100%), 4.8% (2.7%-25%), and 6.8% (5%-22%), respectively. The most frequent CHDs were conotruncal anomalies (36%). There was excellent intercenter agreement (κ = 0.97).

CONCLUSIONS

(1) Four-dimensional volume data sets can be remotely acquired and accurately interpreted by different centers. (2) Among centers with technical expertise, 4DUS is an accurate and reliable method for fetal echocardiography.

Accuracy of four-dimensional spatiotemporal image correlation echocardiography in the prenatal diagnosis of congenital heart defects

OBJECTIVE

To evaluate the accuracy of four-dimensional (4D) spatiotemporal image correlation (STIC) echocardiography for the diagnosis of fetal congenital heart disease (CHD) in a selected high-risk population.

METHODS

Three hundred and sixty-three pregnant women referred for suspected CHD on screening ultrasound were evaluated by means of conventional echocardiography between 14 and 41 weeks' gestation and 4D-STIC volumes were obtained (including gray-scale and color Doppler information). Stored volumes were analyzed, at least 1 year after they had been acquired, by examiners blinded to the patients' identities and outcomes. The STIC diagnoses were compared to those made on conventional two-dimensional echocardiography and the accuracy of diagnosis was assessed with respect to postnatal examination, or autopsy in cases of termination of pregnancy or perinatal death.

RESULTS

The mean gestational age at volume acquisition was 24 + 5 weeks. STIC evaluation was possible in 98% of cases. Twenty-one cases were lost to follow-up, with a total of 167 normal hearts and 175 cases of CHD diagnosed at postnatal evaluation. The overall accuracy, sensitivity, specificity and positive and negative predictive values of STIC in determining the presence or absence of CHD were 91.6, 94.9, 88.1, 89.7 and 94.0%, respectively. Absolute concordance with the final specific diagnosis among cases with confirmed CHD was 74.3% for STIC echocardiography, compared with 81.7% for real-time evaluation.

CONCLUSION

4D-STIC echocardiography performed by experienced operators can be used in fetuses at risk for cardiac anomalies in order to reliably provide reassurance of normality or to accurately diagnose major structural heart defects.

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.

Real-time three-dimensional echocardiography using a matrix probe with live xPlane imaging of the interventricular septum

OBJECTIVE

To describe a technique to rapidly visualize the in-plane view of the fetal interventricular septum (IVS) to enable the identification of a ventricular septal defect (VSD).

METHODS

One hundred and fifty-one women were invited to participate after their routine fetal morphology scan, including four suspected to have congenital cardiac defects which were confirmed postnatally. A standard examination protocol using real-time three-dimensional (3D) echocardiography with live xPlane imaging was developed. The ability of this new technology to examine the ventricular septum was investigated.

RESULTS

The in-plane view of the fetal IVS was visualized successfully in 150 (99.3%) cases by real-time 3D echocardiography with live xPlane imaging, including 82 (54.3%) cases with the spine posterior and 68 (45.7%) cases with the spine anterior. The in-plane view of the IVS successfully visualized the VSDs in three fetuses with VSD and displayed the intact IVS in one fetus with transposition of the great arteries without VSD.

CONCLUSION

We describe live xPlane imaging, a simple method for the real-time assessment of the in-plane view of the IVS that has the potential to enhance the diagnostic accuracy of fetal cardiac examination.

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.

Feasibility and accuracy of fetal echocardiography using four-dimensional spatiotemporal image correlation technology before 16 weeks' gestation

OBJECTIVES

To evaluate the potential value of early fetal echocardiography (EFE) by means of four-dimensional (4D) spatiotemporal image correlation (STIC) technology for either reassurance of normality or prenatal diagnosis of major congenital heart defects (CHDs).

METHODS

Sixty-nine pregnant women from 11 to 15 weeks' gestation underwent EFE. 4D-STIC volumes were acquired by the transvaginal approach for later review by two different examiners. STIC evaluation was considered complete when the four-chamber view, and the origin and double-crossing of the great arteries were identified correctly. Color Doppler imaging was used to detect either septal shunts or transvalvular regurgitation/aliasing suggesting abnormalities. STIC diagnoses were compared with those of conventional EFE. Reliability was assessed by postnatal examination, or autopsy in cases of termination of pregnancy or perinatal death.

RESULTS

The median gestational age at volume acquisition was 13 + 3 weeks. Eleven (15.9%) cases of CHD were diagnosed. A complete EFE was possible in 64 cases. We were able to provide reassurance of normality in 51 of the 53 confirmed normal hearts, with no false-positive results for major defects, although two minor defects (one ventricular septal defect (VSD) and one persistent left superior vena cava) were falsely suspected. The only false negative was a significant VSD at birth overlooked by both observers. Therefore, the total accuracy of STIC-EFE was 95.3% (61/64), with sensitivity, specificity, and positive and negative predictive values of 90.9%, 96.2%, 83.3% and 98.1%. The accuracy of conventional EFE (98.4%, 63/64) was slightly better than that of STIC, with no false-positive results recorded.

CONCLUSIONS

Offline evaluation of 4D-STIC acquired volumes of the fetal heart in the first and early second trimester of pregnancy is reliable not only for early reassurance of normal cardiac anatomy but also to diagnose most major structural heart defects.

[Diagnosis of congenital heart disease in a nonselected population in Upper Normandy: retrospective study between 2003 and 2007]

Routine prenatal ultrasound screening for the detection of possible cardiopathy has existed in Upper Normandy since 1987, including the continuous training of obstetric ultrasonographers. We evaluated the profitability and the expected benefit of prenatal detection in a nonselected population in this region.

METHODS

A retrospective study was undertaken from October 2003 to September 2007 in the cardiopediatric units of Upper Normandy. All fetuses and infants with a diagnosed major cardiac defect were classified into 3 groups: no possibility of anatomic surgical repair (group 1), risk of early decompensation (group 2), and anatomic surgical repair possible but without early decompensation (group 3). Prenatal and postnatal mortality and morbidity were reported.

RESULTS

One hundred and sixty-five major congenital heart defects were detected prenatally and 68 postnatally. The prenatal detection rate was 71% (93, 53, and 77% for groups 1, 2, and 3, respectively; p<0.0001). The rate of pregnancy termination was 92, 17, and 45%, respectively. The mortality rate tended to be higher in the undiagnosed group of urgent neonatal heart cases (10.6% vs 4.4%). The prenatal prevalence of abnormal karyotype was 21% and was 11.5% for congenital malformation syndrome.

CONCLUSION

Prenatal detection of major cardiac defects has continued to attain high success in Upper Normandy. However, 50% of urgent neonatal heart cases often remain undiagnosed, and therefore the neonatologist must treat this patient population with particular care. Prenatal diagnosis can reduce preoperative mortality and morbidity of cardiopathy with a risk of early decompensation with specific neonatal intensive care.

Prenatal detection of trisomy 21 by second-trimester ultrasound examination and maternal age in a non-selected population of 49 314 births in Norway

OBJECTIVES

To assess the contribution of the second-trimester routine ultrasound examination and maternal age (>or= 38 years) to the prenatal detection of trisomy 21 in a large non-selected population in which no other screening methods were carried out.

METHODS

A prospective follow-up study was carried out in a non-selected Norwegian population from 1987 to 2004, including a total of 49 314 births. Data from all cases of trisomy 21, detected prenatally by karyotyping following amniocentesis performed for abnormal ultrasound findings or because of maternal age >or= 38 years, or postnatally after delivery, were registered. The study period was divided into three 6-year periods.

RESULTS

Eighty-eight cases of trisomy 21 were registered. The prenatal detection rate was 43% (38/88). No significant change in the detection rate was observed over the 18 years. Fourteen percent (12/88) of cases were detected as a result of advanced maternal age and 30% (26/88) by prenatal ultrasound examination. Of all women with a trisomy 21 fetus, 72% (63/88) were under 38 years of age. The percentage of women >or= 38 years opting for karyotyping during the three time periods decreased significantly from 51% to 50% and 36%, respectively. The termination rate of trisomy 21 fetuses was 84%, with no significant change over time.

CONCLUSIONS

Our data can be considered as a reference standard for population screening for trisomy 21 based solely on maternal age and second-trimester ultrasound imaging. The prenatal detection rate of trisomy 21 cases was poor and remained unchanged throughout the 18-year study period. If improvement in detection rates is desired, additional programs are necessary.

Prenatal ultrasound detection of facial clefts: a prospective study of 49,314 deliveries in a non-selected population in Norway

OBJECTIVES

To evaluate prenatal detection of facial clefts by ultrasound examination in a large non-selected population, and to study trends in detection rates over 18 years, as well as the prevalence of isolated cases and those with associated anomalies.

METHODS

This prospective follow-up study from January 1987 to December 2004 was divided into two 9-year periods. The study included all registered cases of prenatally or postnatally diagnosed facial clefts in a non-selected population in Norway.

RESULTS

A total of 101 fetuses or newborns with facial clefts in a population of 49 314 deliveries were registered. The distribution of clefts was: 25 (25%) cleft lip, 52 (51%) cleft lip and palate, and 24 (24%) cleft palate (CP). No CP was detected prenatally. Cleft lip with or without cleft palate (CL(P)) was detected prenatally in 35/77 (45%) cases, with a significant increase in the detection rate from 34% to 58% between the two 9-year periods (P = 0.03). Over the whole study period CL(P) was detected at a median of 19 + 2 gestational weeks, with no change over time; altogether 24/35 (69%) cases were detected at the routine second-trimester ultrasound examination. Thirty-three of 77 (43%) cases of CL(P) and 14/24 (58%) cases of CP had associated anomalies; 12/101 (12%) had chromosomal aberrations. In 18/101 (18%) the clefts were part of a syndrome or sequence.

CONCLUSIONS

The detection rate for CL(P) improved significantly over time. Detection of CL(P) is important because nearly half the cases have associated anomalies.

A systematic analysis of the feasibility of four-dimensional ultrasound imaging using spatiotemporal image correlation in routine fetal echocardiography

OBJECTIVES

To investigate the feasibility of incorporating spatiotemporal image correlation (STIC) into a tertiary fetal echocardiography program.

METHODS

During the study period all pregnant women fitting our inclusion criteria were enrolled consecutively. Four sonographers participated in the study, one of whom had substantial previous experience of STIC volume acquisition and three of whom did not. STIC volumes were acquired within the time slot allocated for the usual examination and all attempts were recorded. STIC volumes were assessed on acquisition conditions, the quality (as defined by a checklist of cardiac structures that could be visualized), and the rendering abilities. Furthermore, possible learning effects and the influence of experience with STIC on volume acquisition were studied.

RESULTS

STIC volume acquisition was successful in 75.7% (112/148) of cases in which it was attempted. The more experienced sonographer had a higher success rate in STIC volume acquisition (experienced vs. less experienced, 88.4% vs. 70.5%, P = 0.02). Of all analyzed STIC volumes, 64.8% were of high or sufficient quality. STIC volume quality and rendering ability correlated strongly with the acquisition conditions. High-quality STIC volumes successfully rendered the intracardiac septa in 84.6% of cases. The coronal atrioventricular plane was rendered in 12/26 cases (46.2%).

CONCLUSIONS

This study shows that incorporation of STIC volume acquisition into the daily practice of a tertiary fetal echocardiography program is feasible. Sonographers do not have to be specifically experienced in three- or four-dimensional ultrasound imaging to acquire high-quality STIC volumes. For successful STIC acquisition and subsequent successful analysis, correct acquisition conditions are of major importance. Finally, our results demonstrate that STIC is as susceptible as conventional two-dimensional ultrasound imaging to individual variations and limitations in scanning windows.

Application of automated sonography on 4-dimensional volumes of fetuses with transposition of the great arteries

OBJECTIVE

The purpose of this study was to assess, in second-trimester fetuses with transposition of the great arteries (TGA), the performance of software (sonographically based volume computer-aided analysis) that automatically retrieves diagnostic cardiac planes from a 4-dimensional volume of the fetal chest obtained with spatiotemporal image correlation.

METHODS

We retrospectively evaluated the 4-dimensional spatiotemporal image correlation volumes of 12 fetuses with TGA (complete TGA, 10 cases; correct TGA, 2 cases). The data were analyzed to determine whether the target diagnostic planes, that is, cardiac plane 1 (left ventricle outflow tract) and cardiac plane 2 (right ventricle outflow tract), were correctly identified in at least 1 of the 7 automatically generated tomographic sonographic image displays and whether they allowed diagnosis of TGA.

RESULTS

In 9 of 10 fetuses with complete TGA, target diagnostic cardiac plane 1 showed a branching arterial vessel (pulmonary artery) arising from the left ventricle, whereas in 7 of 10 fetuses, the aorta arising from the right ventricle was shown. In both cases with correct TGA, the pulmonary artery starting from the morphologic left ventricle was shown, whereas in 1 of 2, the connection of the aorta with the morphologic right ventricle was found. In all of the fetuses with TGA, a ventricular arterial connection anomaly was shown in either cardiac plane 1 or 2.

CONCLUSIONS

This automatic approach shows good retrieval of diagnostic cardiac planes in fetuses with TGA, which may improve diagnostic efficacy for this disease.

Automated retrieval of standard diagnostic fetal cardiac ultrasound planes in the second trimester of pregnancy: a prospective evaluation of software

OBJECTIVE

To evaluate prospectively the performance of software that automatically retrieves, from a three-dimensional (3D) volume of the fetal chest, three diagnostic cardiac planes in the second trimester of pregnancy.

METHODS

3D static volumes of the fetal chest were acquired at the level of the four-chamber view in 72 fetuses between 18 and 23 weeks of gestation. Standardization of 3D volumes was performed in Plane A (the reference plane: four-chamber view) alone. Tomographic ultrasound imaging (TUI) was added to the display of each diagnostic plane. The left ventricular outflow plane (Cardiac plane 1: five-chamber view, aorta), the right ventricular outflow plane (Cardiac plane 2: pulmonary artery) and the abdominal circumference plane (Cardiac plane 3: abdominal circumference, stomach) were retrieved by the software from the 3D volumes and the data were analyzed to determine whether Cardiac planes 1-3 were displayed correctly in each volume.

RESULTS

The automated software displayed, in at least one TUI plane, target Cardiac plane 1 in 94.4% of volumes, target Cardiac plane 2 in 91.7% of volumes and target Cardiac plane 3 in 97.2% of volumes.

CONCLUSION

Our results validate the concept of automated sonography and its potential clinical applicability.

Prenatal ultrasound detection of talipes equinovarus in a non-selected population of 49 314 deliveries in Norway

OBJECTIVES

To evaluate prenatal ultrasound detection of talipes equinovarus (TEV) in a large non-selected population and to study trends in detection rates over time, as well as the prevalence and outcome of isolated TEV and TEV with associated anomalies.

METHODS

All cases of pre- or postnatally diagnosed TEV between 1987 and 2004 within a non-selected population of 49 314 deliveries were investigated. The study period was divided into three 6-year periods to shed light on changes in detection rates and other aspects of the anomaly over time.

RESULTS

A total of 113 cases of TEV were registered during the 18-year period, of which 49% had isolated TEV and 51% had associated anomalies. During the three 6-year periods, there was a significant improvement (P = 0.006) in the overall detection of TEV from 43% to 67% and 77%, respectively. The detection rate for isolated TEV increased over time. Isolated bilateral TEV cases were detected more than twice as often as isolated unilateral TEV. The three largest groups of associated anomalies were syndromes/sequences (26%), chromosome aberrations (26%), and musculoskeletal disorders (24%). Pregnancies were terminated in 23% of the cases, all with severe additional anomalies. Treatment of TEV included surgery in 86% of the cases.

CONCLUSION

The overall detection rate of TEV improved significantly over time. Prenatal detection was higher when TEV was bilateral and when other associated anomalies were present. Parents should be informed that, in suspected isolated TEV, associated anomalies might remain undetected prenatally.

Prenatal diagnosis of structural cardiac defects

Prenatal diagnosis of congenital heart defects has been possible now for over 25 years. This ability has extended from a few specialists to being within the scope of any sonographer engaged in routine obstetric evaluation of the low-risk patient. However, the detection rate is widely varied. The recognition of major structural heart disease in fetal life has important implications for the child's future, so further efforts should be made to improve the success in diagnosis.

Three-Dimensional Echocardiography for Studies of the Fetal Heart: Present Status and Future Perspectives

Three-dimensional (3D) ultrasound of the fetal heart is increasingly being used in prenatal diagnosis. While very detailed fetal cardiac studies can be performed using the various 3D ultrasound modalities, their utility for screening for fetal heart disease is yet to be proven. With the emergence of even newer technologies such as quantification techniques and two-dimensional matrix arrays, further improvements are imminent.

Four-dimensional ultrasonography of the fetal heart using a novel Tomographic Ultrasound Imaging display

OBJECTIVE

The objective of this study was to investigate the feasibility of examining the fetal heart with Tomographic Ultrasound Imaging (TUI) using four-dimensional (4D) volume datasets acquired with spatiotemporal image correlation (STIC).

MATERIAL AND METHODS

One hundred and ninety-five fetuses underwent 4D ultrasonography (US) of the fetal heart with STIC. Volume datasets were acquired with B-mode (n=195) and color Doppler imaging (CDI) (n=168), and were reviewed offline using TUI, a new display modality that automatically slices 3D/4D volume datasets, providing simultaneous visualization of up to eight parallel planes in a single screen. Visualization rates for standard transverse planes used to examine the fetal heart were calculated and compared for volumes acquired with B-mode or CDI. Diagnoses by TUI were compared to postnatal diagnoses.

RESULTS

(1) The four- and five-chamber views and the three-vessel and trachea view were visualized in 97.4% (190/195), 88.2% (172/195), and 79.5% (142/195), respectively, of the volume datasets acquired with B-mode; (2) these views were visualized in 98.2% (165/168), 97.0% (163/168), and 83.6% (145/168), respectively, of the volume datasets acquired with CDI; (3) CDI contributed additional diagnostic information to 12.5% (21/168), 14.2% (24/168) and 10.1% (17/168) of the four- and five-chamber and the three-vessel and trachea views; (4) cardiac anomalies other than isolated ventricular septal defects were identified by TUI in 16 of 195 fetuses (8.2%) and, among these, CDI provided additional diagnostic information in 5 (31.3%); (5) the sensitivity, specificity, positive- and negative-predictive values of TUI to diagnose congenital heart disease in cases where both B-mode and CDI volume datasets were acquired prenatally were 92.9%, 98.8%, 92.9% and 98.8%, respectively.

CONCLUSION

Standard transverse planes commonly used to examine the fetal heart can be automatically displayed with TUI in the majority of fetuses undergoing 4D US with STIC. Due to the retrospective nature of this study, the results should be interpreted with caution and independently confirmed before this methodology is introduced into clinical practice.