Improving the effectiveness of routine prenatal screening for major congenital heart defects

Newborns with congenital heart diseases: epidemiological data from a single reference center in Brazil

OBJECTIVE

to describe the epidemiological data of the population born with the diagnosis of Congenital Heart Disease (CHD); to compare diagnoses made using fetal echocardiography with the findings from postnatal echocardiography or anatomopathological examination of the heart; and to evaluate mortality among newborns that underwent surgical treatment.

METHODS

this was a cohort study with information gathered from the medical records of the pregnant women and their newborns diagnosed with CHD during the fetal or postnatal periods, between January 2008 and December 2012. Means, standard deviations and maximum and minimum values were calculated for the quantitative variables. Relative and absolute values were calculated for the qualitative variables. The heart malformations were categorized in four groups: complex lesions, significant lesions, minor lesions and others.

RESULTS

we detected postnatal incidence of CHD of 1.9% at our service. The mean maternal age was 28.3 years and 10 (21.3%) of the pregnant women were ≥ 35 years old. The mean gestational age at the time of performing the fetal echocardiogram was 27.8 weeks. Mean gestational age at delivery was 38 weeks, and the mean weight of the newborns was 2,644.5 grams. Regarding the diagnosis of CHD, there were: 23 complex lesions (39%); 15 significant lesions (26%); 10 minor lesions (17%); 4 other lesions (7%) and 6 normal anatomies (10%). The diagnosis of CHD made on the fetus and postnatally coincided in 77.6% of the cases. A total of 27 patients (60%) underwent surgery, and the outcome was neonatal death in five cases.

CONCLUSION

we detected postnatal incidence of CHD of 1.9%, and it was more common among older pregnant women and with late detection in the intrauterine period. Complex heart diseases predominated, thus making it difficult to have a good result regarding neonatal mortality rates.

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.

Fetal heart defects: potential and pitfalls of first-trimester detection

Congenital heart defects (CHDs) are the leading cause of infant mortality due to birth defects. In the last 15 years, with the shift in screening for aneuploidies to the first trimester, extensive research has concentrated on early screening and detection of CHDs. Early detailed assessment of the fetal heart requires a high level of expertise in early anomaly scanning and fetal echocardiography. However, the detection of major CHDs at 11-13 weeks is influenced by their association with easily detectable markers, such as the nuchal translucency, ductus venosus blood flow and tricuspid regurgitation, and a policy decision as to the objectives of this scan and the allocation of resources necessary to achieve them. The use of transvaginal ultrasound and newer techniques are likely to improve the detection rate. However, the limitations of fetal echocardiography in the first trimester must be borne in mind, and follow-up at mid-gestational echocardiography is prudent in some cases.

Hemoglobin A1c in pregestational diabetic gravidas and the risk of congenital heart disease in the fetus

This study aimed to determine whether poor glycemic control in early pregnancy is associated with an increased risk of congenital heart disease (CHD) for infants of women with preexisting diabetes. A retrospective review examined two tertiary care centers of diabetic pregnancies that recorded early hemoglobin A1c (HbA1c) values (<20 weeks). The incidence of prenatally diagnosed CHD was calculated and stratified by HbA1c level. Poor glycemic control was defined as an HbA1c level of 8.5 % or higher. Fetal echocardiography was used to identify fetuses that resulted in infants with suspected CHD. Neonatal echocardiograms and pathology reports were reviewed for confirmation of the diagnosis. Of 535 patients, 30 (5.6 %) delivered an infant with confirmed CHD. Among the patients with poor glycemic control, 8.3 % (n = 17) delivered an infant with CHD, whereas 3.9 % (n = 13) of those with an HbA1c level lower than 8.5 % delivered an infant with CHD (p = 0.03). Poor glycemic control in early pregnancy is associated with an increased risk of CHD in offspring. The incidence of CHD in patients with adequate glycemic control still is sufficiently high to justify routine fetal echocardiography for all gravidas with preexisting diabetes regardless of HbA1c level.

Fetal Intelligent Navigation Echocardiography (FINE): a novel method for rapid, simple, and automatic examination of the fetal heart

OBJECTIVE

To describe a novel method (Fetal Intelligent Navigation Echocardiography (FINE)) for visualization of standard fetal echocardiography views from volume datasets obtained with spatiotemporal image correlation (STIC) and application of 'intelligent navigation' technology.

METHODS

We developed a method to: 1) demonstrate nine cardiac diagnostic planes; and 2) spontaneously navigate the anatomy surrounding each of the nine cardiac diagnostic planes (Virtual Intelligent Sonographer Assistance (VIS-Assistance®)). The method consists of marking seven anatomical structures of the fetal heart. The following echocardiography views are then automatically generated: 1) four chamber; 2) five chamber; 3) left ventricular outflow tract; 4) short-axis view of great vessels/right ventricular outflow tract; 5) three vessels and trachea; 6) abdomen/stomach; 7) ductal arch; 8) aortic arch; and 9) superior and inferior vena cava. The FINE method was tested in a separate set of 50 STIC volumes of normal hearts (18.6-37.2 weeks of gestation), and visualization rates for fetal echocardiography views using diagnostic planes and/or VIS-Assistance® were calculated. To examine the feasibility of identifying abnormal cardiac anatomy, we tested the method in four cases with proven congenital heart defects (coarctation of aorta, tetralogy of Fallot, transposition of great vessels and pulmonary atresia with intact ventricular septum).

RESULTS

In normal cases, the FINE method was able to generate nine fetal echocardiography views using: 1) diagnostic planes in 78-100% of cases; 2) VIS-Assistance® in 98-100% of cases; and 3) a combination of diagnostic planes and/or VIS-Assistance® in 98-100% of cases. In all four abnormal cases, the FINE method demonstrated evidence of abnormal fetal cardiac anatomy.

CONCLUSIONS

The FINE method can be used to visualize nine standard fetal echocardiography views in normal hearts by applying 'intelligent navigation' technology to STIC volume datasets. This method can simplify examination of the fetal heart and reduce operator dependency. The observation of abnormal echocardiography views in the diagnostic planes and/or VIS-Assistance® should raise the index of suspicion for congenital heart disease.

Performance of different scan protocols of fetal echocardiography in the diagnosis of fetal congenital heart disease: a systematic review and meta-analysis

OBJECTIVE

The rapid progress in fetal echocardiography has lead to early detection of congenital heart diseases. Increasing evidences have shown that prenatal diagnosis could be life saving in certain cases. However, there is no agreement on which protocol is most adaptive diagnostic one. Thus, we use meta-analysis to conduct a pooled performance test on 5 diagnostic protocols.

METHODS

We searched PUBMED, EMBASE, the Cochrane Central Register of Controlled Trials and WHO clinical trails registry center to identify relevant studies up to August, 2012. We performed meta-analysis in a fixed/random-effect model using Meta-disc 1.4. We used STATA 11.0 to estimate the publication bias and SPSS 17.0 to evaluate variance.

RESULTS

We use results from 81 studies in 63 articles to analyze the pooled accuracy. The overall performance of pooled sensitivities of spatiotemporal image correlation (STIC), extend cardiac echography examination (ECEE) and 4 chambers view + outflow tract view + 3 vessels and trachea view (4 CV+OTV+3 VTV) were around 0.90, which was significant higher than that of 4 chambers view + outflow tract view or 3 vessels and trachea view (4 CV+OTV/3 VTV) and 4 chambers view (4 CV). Unfortunately the pooled specificity of STIC was 0.92, which was significant lower than that of other 4 protocols which reached at 1.00. The area under the summary receiver operating characteristic curves value of STIC, ECEE, 4 CV+OTV+3 VTV, 4 CV+OTV/3 VTV and 4 CV were 0.9700, 0.9971, 0.9983, 0.9929 and 0.9928 respectively.

CONCLUSION

These results suggest a great diagnostic potential for fetal echocardiography detection as a reliable method of fetal congenital heart disease. But at least 3 sections view (4 CV, OTV and 3 VTV) should be included in scan protocol, while the STIC can be used to provide more information for local details of defects, and can not be used to make a definite diagnosis alone with its low specificity.

Increasing the detection rate of congenital heart disease during routine obstetric screening using cine loop sweeps

OBJECTIVES

The purpose of this study was to demonstrate an increase in the detection rate of fetal cardiac defects using 2 cine loop sweeps.

METHODS

Image reviewers examined a series of 93 cases randomly sorted, including 79 studies with normal findings and 14 studies with abnormal findings. All of the images were assessed by 5 standard criteria. Cases were classified as normal, abnormal, or indeterminate. Reviewers using the conventional approach reviewed 3 still images: the 4-chamber, left ventricular outflow tract, and right ventricular outflow tract views. Reviewers using the cine loop sweeps viewed 2 grayscale sweeps through the fetal heart in real time. The image sequences were reviewed independently by 2 experts, 3 nonexperts, and 2 sonographers blinded to each others' results.

RESULTS

The cine loop sweeps had an increased detection rate of 38% for the nonexperts and 36% for the experts compared with the conventional approach. The cine loop sweeps allowed identification of all cardiac defects by at least 2 of the 7 reviewers; the percentage of cases with false-positive findings was 3.9%. With the conventional approach, 2 defects went undetected by all reviewers, and 4 defects were found by only 1 reviewer; the percentage of cases with false-positive findings was 5.4%.

CONCLUSIONS

The use of cine loop sweeps has the potential to increase the detection of fetal cardiac defects without increasing the rate of false-positive findings or increasing the interpretation and decision-making times.

The Cost-Effectiveness of Prenatal Detection for Congenital Heart Disease Using Telemedicine Screening

We estimated the longer-term cost-effectiveness of using telemedicine screening for prenatal detection of congenital heart disease (CHD). One hospital in south-east England with a telemedicine service was connected to a fetal cardiology unit in London. A UK health service perspective was adopted. Evidence on costs and outcomes for standard-risk pregnant women during the antenatal period was based on patient-level data. Extrapolation beyond the end of the study (just after delivery) was carried out for the lifetime of children born with and without CHD. Expert opinion and data from published sources was used to populate a decision model. Future costs and benefits were discounted. The main outcome was quality-adjusted life years (QALYs) and results were expressed as cost per QALY gained. Various one-way sensitivity analyses were conducted. The model showed that offering telemedicine screening by specialists to all standard-risk pregnant women was the dominant strategy (i.e. cheaper and more effective). The sensitivity analyses found that the model was robust, and that telemedicine remained the most cost-effective strategy. The study showed that it would be cost-effective to provide telemedicine examinations as part of an antenatal screening programme for all standard-risk women.

Education in obstetrical ultrasound--an important factor for increasing the prenatal detection of congenital heart disease

OBJECTIVE

To evaluate the effects of postgraduate education in obstetrical ultrasound on the prenatal detection rate of congenital heart disease.

SETTING

Tertiary care center.

POPULATION

Experienced and less experienced midwives performing ultrasound scans.

METHODS

Number of fetuses and live-born children with severe congenital heart malformations were extracted from patient records. The detection rates of experienced and less experienced midwives were compared following a postgraduate training program in obstetrical ultrasound.

MAIN OUTCOME MEASURES

The prenatal detection rate of complex congenital heart malformations.

RESULTS

The prenatal detection rate for the entire unit increased significantly during the study period (32 vs. 69%, p < 0.05). Following education, we observed a significant increase in detection rates (21 vs. 67%, p < 0.01) among experienced midwives. In the group of less experienced midwives, we found a positive effect of training with considerably higher detection rates compared with results achieved by their more experienced colleagues before the program (40 vs. 21%).

CONCLUSION

There is a clear improvement in the prenatal detection rates of complex heart malformations following a postgraduate education in obstetrical ultrasound. Similar training should be offered to both midwives and doctors performing routine scans to increase the standards of antenatal screening for congenital heart disease.

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.

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.

Outcome of fetal echocardiography: a 17 year single-institution experience in Japan

BACKGROUND

The aim of this retrospective study was to evaluate the influence of prenatal diagnosis on perinatal outcomes of congenital heart disease (CHD) over a 17 year period at a single center.

METHODS

The perinatal outcome of CHD in 146 patients diagnosed on fetal echocardiography between 1994 and 2010 were reviewed. The characteristics of 193 neonatal inpatients with CHD treated at the authors' department between 2001 and 2010 were also analyzed; among the inpatients, 61 were diagnosed before birth (prenatal group) and 132 were diagnosed after birth (postnatal group).

RESULTS

Among the 146 patients prenatally diagnosed with CHD, the prenatal mortality, including abortion and stillbirth, decreased from 1994 to 2010. Among the 193 neonatal inpatients, the prenatal group had lower gestational age and bodyweight than the postnatal group. Further, the prenatal group had lower blood pH at admission, but no patient in that group experienced ductal shock, although six patients in the postnatal group did. The average dose of prostaglandin E1 used in duct-dependent CHD was significantly lower in the prenatal group than in the postnatal group (3.4 vs. 4.6 ng/kg per min; P = 0.015).

CONCLUSIONS

Prenatal diagnosis of CHD enables planned labor, prevents ductal shock, and reduces prostaglandin E1 side-effects and medical expenditure.

Early fetal anatomical sonography

Over the past decade, prenatal screening and diagnosis has moved from the second into the first trimester, with aneuploidy screening becoming both feasible and effective. With vast improvements in ultrasound technology, sonologists can now image the fetus in greater detail at all gestational ages. In the hands of experienced sonographers, anatomic surveys between 11 and 14 weeks can be carried out with good visualisation rates of many structures. It is important to be familiar with the normal development of the embryo and fetus, and to be aware of the major anatomical landmarks whose absence or presence may be deemed normal or abnormal depending on the gestational age. Some structural abnormalities will nearly always be detected, some will never be and some are potentially detectable depending on a number of factors.

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.

Increased nuchal translucency and congenital heart disease

Sonographic assessment of fetal nuchal translucency (NT) thickness is the cornerstone of screening for chromosomal abnormality at 11-13(+6) weeks gestation. This marker was first recognized in pregnancies being karyotyped for advanced maternal age, but its underlying pathophysiology remains to be fully determined. Although increased NT is clearly associated with changes in both lymphatic and cardiac development, neither is an obvious causative agent. The association with cardiac defects has now being subjected to a significant amount of research, with a large body of evidence showing that this marker is also a screening tool for major cardiac defects - although it performs more modestly than for chromosomal abnormality. The field continues to change rapidly. Recent evidence that uses a combination of increased NT, tricuspid regurgitation and abnormal flow in the 'a' wave of the ductus venosus can provide an effective screening strategy to predict many major cardiac defects at this early stage of pregnancy.

Role of fetal echocardiography in stepwise sequential screening for chromosomal disorders (combined test associated with modified genetic sonography)

OBJECTIVES

To evaluate the contribution made by fetal echocardiography in identifying Down's syndrome (DS) and other chromosomal disorders in a stepwise sequential screening method (first step: combined test (CT), second step: modified genetic sonography (MGS) (major malformation and nuchal fold)), for DS in the general population of pregnant women.

METHODS

Prospective study. During a 5-year study period (July 2005-June 2010) 17,911 pregnant women underwent CTs with MGS (with fetal cardiac morphological evaluation performed by obstetricians in a tertiary hospital) as a screening method for DS. We evaluated the sensitivity and false positive rate (FPR) (95% confidence interval (CI)) of three screening methods for DS and all chromosomal disorders: CT, CT + MGS, and CT + fetal echocardiography.

RESULTS

A total of 17,911 cases were analyzed with 67 chromosome disorders and 45 DS cases being found. For DS, the CT sensitivity was 80% (95% CI; 68.3-91.7) (36/45) and 79.1% (95% CI; 69.4-88.8) (53/67) for all chromosome disorders, with a FPR of 4.2% (95% CI; 3.9-4.5) (752/17,866) and 4.1% (95% CI; 3.8-4.4) (735/17,844), respectively. For CT + MSG and CT + fetal echocardiography, the sensitivity for DS was 93.3% (95% CI; 85.9-0.99) (42/45) and 95.5% (95% CI; 90.5-0.99) (64/67) for all chromosome disorders. The FPR for CT + MSG was 4.8% (95% CI; 4.5-5.1) (860/17,866) and 4.6% (95% CI; 4.3-4.9) (836/17,844), respectively. The FPR of CT + fetal echocardiography was 4.4% (95% CI; 4.1-4.7) (792/17,866) for DS screening and 4.3% (95% CI; 4-4.6) (770/17,844) for chromosome abnormality screening.

CONCLUSIONS

Fetal echocardiography is highly capable of identifying DS and other chromosomal disorders as a part of genetic sonography in stepwise sequential screening.

Congenital cardiac anomalies: prenatal readings versus neonatal outcomes

OBJECTIVE

The purpose of this study was to determine the variation between prenatal and postnatal diagnosis of congenital cardiac lesions diagnosed by both fetal center primary physicians and fetal pediatric cardiologists at a single tertiary referral center in the United States and evaluate why cases were misdiagnosed.

METHODS

A retrospective review of all cardiac abnormalities identified prenatally by level II sonography at a tertiary referral fetal center between January 2006 and December 2008 was performed to include any patient with a fetal cardiac abnormality and with a documented autopsy or neonatal follow-up. Congenital heart disease diagnoses were classified as correct, incorrect, or incorrect but within the same spectrum of disease. Cases of correct diagnosis by primary physicians and pediatric cardiologists were compared.

RESULTS

Sixty patients with fetal heart abnormalities were identified among 8894 patients who had level II sonography. The combined detection rate for fetal heart abnormalities for both primary physicians and pediatric cardiologists together was 81.7%. The detection rates of congenital heart disease were not statistically different between primary physicians and pediatric cardiologists: 77.9% (46 of 59) versus 85.0% (34 of 40; P = .3). The most common cardiac abnormalities misdiagnosed in our study population included pulmonic stenosis, ventricular septal defect, myxoma, truncus arteriosus, and coarctation of the aorta.

CONCLUSIONS

Congenital heart disease is misdiagnosed in tertiary care centers by both pediatric cardiologists and fetal imaging specialists. We believe that this occurrence is related to multiple factors, including evolution of congenital heart disease, maternal body habitus, associated congenital anomalies, decreased amniotic fluid volume, gestational age at evaluation, imaging techniques, and, most importantly, the experience of the sonographer.

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.

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.

Contemporary clinical applications of spatio-temporal image correlation in prenatal diagnosis

PURPOSE OF REVIEW

Four-dimensional fetal echocardiography has the potential to reduce the operator dependency of two-dimensional ultrasonography and increase the detection rate of congenital heart defects (CHDs). This review is intended to summarize recent evidence of the important role that four-dimensional ultrasonography with spatio-temporal image correlation (STIC) may play in the prenatal diagnosis of CHDs.

RECENT FINDINGS

Four-dimensional ultrasonography with STIC may provide the opportunity for telemedicine in the prenatal diagnosis of CHDs because four-dimensional volume datasets can be remotely acquired and accurately interpreted by different centers. Four-dimensional ultrasonography with STIC is an accurate and reproducible technique for the prenatal diagnosis of CHDs. Different four-dimensional rendering techniques can provide important insight into the spatial relationships of normal and abnormal fetal vascular structures.

SUMMARY

Four-dimensional fetal echocardiography with STIC may facilitate the examination of the fetal heart and could potentially increase the detection rate of CHDs.

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.

Simple targeted arterial rendering (STAR) technique: a novel and simple method to visualize the fetal cardiac outflow tracts

OBJECTIVE

To describe a novel and simple technique—simple targeted arterial rendering (STAR)—to visualize the fetal cardiac outflow tracts from dataset volumes obtained with spatiotemporal image correlation (STIC) and applying a new display technology (OmniView).

METHODS

We developed a technique to image the outflow tracts by drawing three dissecting lines through the four-chamber view of the heart contained in a STIC volume dataset. Each line generated the following plane: (a) Line 1: ventricular septum en face with both great vessels (pulmonary artery anterior to the aorta); (b) Line 2: pulmonary artery with continuation into the longitudinal view of the ductal arch; and (c) Line 3: long-axis view of the aorta arising from the left ventricle. The pattern formed by all three lines intersecting approximately through the crux of the heart resembles a star. The technique was then tested in 50 normal fetal hearts at 15.3–40.4 weeks' gestation. To determine whether the technique could identify planes that departed from the normal images, we tested the technique in four cases with proven congenital heart defects (ventricular septal defect (VSD), transposition of great vessels, tetralogy of Fallot and pulmonary atresia with intact ventricular septum).

RESULTS

The STAR technique was able to generate the intended planes in all 50 normal cases. In the abnormal cases, the STAR technique allowed identification of the VSD, demonstrated great vessel anomalies and displayed views that deviated from what was expected from the examination of normal hearts.

CONCLUSIONS

This novel and simple technique can be used to visualize the outflow tracts and ventricular septum en face in normal fetal hearts. 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 involving the great vessels and/or the ventricular septum. The STAR technique may simplify examination of the fetal heart and could reduce operator dependency.

Early diagnosis and screening of congenital cardiac anomalies

Considerable numbers of congenital cardiac anomalies are missed at the time of delivery. Study reports show that congenital cardiac anomalies are the second most common birth defect in many countries. Despite this fact, our previous study showed that the prevalence of congenital cardiac anomalies is the fifth most common one, indicating that many of these defects might not be properly diagnosed at the time of delivery and birth. The aim of this study was to estimate the missing frequency of congenital cardiac anomalies at the time of delivery and birth. The population of the study was 185,650 births in the Northwest region of Iran covered by the Tabriz Registry of Congenital Anomalies. A total of 451 children with congenital cardiac anomalies were studied in the region from 2000 to 2009. The expected prevalence of congenital cardiac anomalies at birth was estimated to be 24.2 per 10,000 births while a prevalence of 9.2 per 10,000 births was observed at the same time and place. This indicated that 59.1% of children with congenital cardiac anomalies were not identified at birth (p-value less than 0.05). This proportion increased by 13% over the study period from 2000 to 2009 (p-value greater than 0.1). Our findings indicated that a remarkable frequency of congenital cardiac anomalies was not diagnosed at birth because there was no paediatric cardiologist available at the time of birth in the gynaecology and obstetrics wards.

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.

Evaluation of nuchal translucency measurement in first trimester pregnancy

BACKGROUND

A significant number of pregnancies, particularly in women with previous histories of infertility, are associated with fetal abnormalities. Methods such as the nuchal translucency (NT) measurement enable us to identify more pregnancies with chromosomal abnormalities.

MATERIALS AND METHODS

This analytic cross-sectional study was performed in 446 pregnant women at 11-14 weeks gestation, from 2009 to 2010 in the Fetal Medicine Unit of Imam Khomeini Hospital, Ahvaz Jundishapur University of Medical Sciences. All NT measurements were performed by a certified sonographer using the Fetal Medicine Foundation (FMF) recommended protocol. FMF first trimester software was used for primary and secondary (adjusted) risk calculation.

RESULTS

The average maternal age was 28.5 years and 15% of mothers were ≥35 years of age. The average crown rump length (CRL), gestational age and NT thickness were 61.7, 12.4 weeks and 1.75 mm, respectively. There were 20 cases with increased adjusted risk (4.04%) and 4 cases of documented abnormal karyotype.

CONCLUSION

In our study increased adjusted risk was 4.04%.Documented abnormal karyotype were 0.9% and 28% of total and high-risk groups who accepted amniocentesis, respectively. In this study, 50% of women with high-risk results and about half of those with abnormal karyotypes were seen in women under age 35. Knowing these risks is of utmost importance in pregnancy, particularly in patients with infertility histories.

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.

Impact of a regional training program in fetal echocardiography for sonographers on the antenatal detection of major congenital heart disease

OBJECTIVES

The aims of this study were to ascertain the effect of a regional training program in fetal echocardiography for obstetric radiographers on the antenatal detection of major congenital heart disease (CHD) and to document short-term outcomes for major CHD.

METHODS

All 87 obstetric radiographers in Northern Ireland were invited to attend 2.5 days of training during a 1-year period. Data were collected before and after the training, over a 5-year study period, to assess the effect of training on the antenatal detection of CHD in the population.

RESULTS

The antenatal detection of major CHD rose significantly, from 28% (72/262) pretraining to 43% (36/84) in the year of training (P = 0.008). Antenatal diagnosis of four-chamber-view defects rose significantly (from 38% to 54%; P = 0.04), as did detection of outflow-tract-view defects (from 8% to 21%; P = 0.05). Twelve per cent (13/108) of cases died spontaneously in utero and 8% (9/108) were terminated. Only 78% (67/86) of live-born cases in which CHD had been diagnosed antenatally survived the neonatal period, compared to 93% (221/238) with a postnatal diagnosis of CHD (P < 0.001).

CONCLUSIONS

Even with a relatively simple training program, significant improvements can be made in the antenatal detection of CHD. With training, obstetric sonographers can successfully assess outflow tracts. Antenatally diagnosed cases have more complex CHD and this probably contributes to poor neonatal survival.

Perinatal diagnosis of heart defects

IMPORTANCE OF THE FIELD

Heart defects are the most frequent congenital malformations, affecting 8 in every 1000 neonates. As 90% of infants born with a congenital heart defects (CHD) have no known risk factor, screening for heart defects in every routine obstetric ultrasound is essential for antenatal diagnosis.

AREAS COVERED IN THIS REVIEW

Two-dimensional echocardiography allied with three- and four-dimensional technologies such as spatio-temporal image correlation offer means for thoroughly evaluating fetal cardiac anatomy.

WHAT THE READER WILL GAIN

This article reviews the most relevant aspects of antenatal screening and diagnosis of CHD using sonography and echocardiography. It includes first trimester diagnosis and three- and four-dimensional techniques.

TAKE HOME MESSAGE

These antenatal diagnostic tools play an important role in optimization of obstetric care and neonatal management, thus potentially reducing perinatal mortality.

Single umbilical artery and congenital heart disease in selected and unselected populations

OBJECTIVE

A variable association between single umbilical artery (SUA) and congenital heart disease (CHD) has been reported previously. Discrepancies in the results may be related to the populations studied. In this study we assessed the relationship between SUA and CHD in two well-defined selected and unselected populations.

METHODS

This was a retrospective review of all cases of SUA detected antenatally in a tertiary referral center between 1997 and 2003. Umbilical arteries were routinely identified around the fetal bladder by color-flow Doppler ultrasonography. The unselected population included pregnancies from a well-defined geographical area, delivering in the same hospital. The selected group was referred from other hospitals because of suspected abnormalities or other risk factors. Major CHD was defined as CHD needing postnatal treatment or long-term follow-up.

RESULTS

There were 10 fetuses with major CHD in the selected group: four cases among 25 with extracardiac defects (16%; 95% CI, 4.5-36.1%) and six cases out of 22 with no other abnormalities (27%; 95% CI, 10.7-50.2%; P = 0.35). In the unselected group there were two cases of major CHD, both among the 13 fetuses with extracardiac abnormalities (15%; 95% CI, 2-45%), while there were no major cardiac defects in the 85 fetuses with SUA and no extracardiac abnormalities (0%; 95% CI, 0-4%; P = 0.03).

CONCLUSIONS

The association between SUA and CHD varies dramatically with population selection criteria. The risk for CHD after the detection of SUA in an otherwise apparently normal fetus from an unselected population seems small and may not warrant specialist fetal echocardiography.

Fetal diagnosis of interrupted aortic arch

To determine the frequency of prenatal detection among liveborn patients with an interrupted aortic arch (IAA), the accuracy of prenatal diagnosis, and the anatomic features associated with IAA in the fetus. The prenatal diagnosis of an IAA is challenging. The data on the features and outcomes of fetal IAA are limited. This was a retrospective review of the fetuses and neonates diagnosed with IAA at the Children's Hospital Boston. From 1988 to 2009, 26 fetuses were diagnosed with an IAA. Of these, 21 were live born, and 5 pregnancies were terminated. Of these 21 patients, 18 were confirmed to have an IAA after birth and 3 had severe aortic coarctation. Of the 56 patients diagnosed with an IAA as neonates, 3 had a prenatal echocardiogram that did not include the correct diagnosis. Among the liveborn patients with a postnatally confirmed IAA, 24% were diagnosed prenatally, which increased from 11% during the first 7-year period to 43% more recently. Also, 15% of the prenatally diagnosed patients with IAA had a family history of structural or genetic anomalies. In fetuses with an IAA, echocardiographic Z-scores for the aortic valve and ascending aorta were significantly lower than in normal fetuses, but the left ventricular dimensions were normal. Aortopulmonary diameter ratios were abnormally low. In conclusion, although the identification of IAA on a prenatal echocardiogram can be challenging, a number of anatomic features can facilitate the diagnosis. In particular, a low aortopulmonary diameter ratio in the absence of a ventricular size discrepancy should prompt consideration of this diagnosis. Despite the diagnostic challenges, the frequency of prenatal diagnosis of the IAA is increasing.

Screening fetal echocardiography in diabetic mothers with normal findings on detailed anatomic survey

OBJECTIVES

To evaluate the benefit of second-trimester fetal echocardiography for women with diabetes whose fetuses had no obvious heart disease on a detailed anatomic survey performed at skilled, high-volume obstetric centers, and to investigate the technical limitations of fetal echocardiography in this patient population.

METHODS

This was a retrospective descriptive review of fetal echocardiograms performed at Children's Hospital Boston from 2000 to 2005. All women referred during the second trimester for fetal echocardiography because of maternal diabetes were included. Those with severe heart disease suspected on obstetric ultrasound examination were excluded.

RESULTS

There were 584 initial fetal echocardiograms. No patients were diagnosed with severe heart disease prenatally. Nineteen were diagnosed with suspected mild heart disease (such as small ventricular septal defect), five of whom had normal follow-up fetal evaluation and five of whom had normal postnatal evaluation. Most of these pregnancies did not have a postnatal cardiac evaluation. Forty-seven fetuses had benign cardiac findings. Nearly one third of patients had imaging that was felt to be limited or incomplete, mostly due to poor acoustic windows. Forty-eight patients were asked to return for at least one follow-up visit, most due to the inability to complete the exam at the initial visit.

CONCLUSIONS

In an environment with access to high-volume, skilled comprehensive ultrasound services, fetal echocardiography by a pediatric cardiology program adds little to the care of women with diabetes and no suspected heart disease on a detailed anatomic survey. Poor acoustic windows frequently necessitate multiple visits.

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.

Application of the 3-vessel view in routine prenatal sonographic screening for congenital heart disease

OBJECTIVES

The purpose of this study was to evaluate the diagnostic accuracy of prenatal screening for congenital heart disease (CHD) based on a combination of the 4-chamber view and 3-vessel view in an unselected population.

METHODS

A prospective study on 8025 scanned fetuses was performed. All singleton pregnancies scheduled for routine prenatal sonographic screening at 20 to 24 weeks' gestation and subsequently delivered in our unit were included. Data were recorded regarding visualization of the 4-chamber view, outflow tracts, and 3-vessel view. Suspected CHD was confirmed by postmortem or postnatal echocardiography. We obtained follow-up data for the neonates and calculated the diagnostic accuracy of the examinations.

RESULTS

Major CHD was identified in 32 cases (4.0%), of which 26 (81.3%) were diagnosed antenatally and 6 (18.7%) postnatally. Four cases (0.5%) had false-positive findings. Twenty-one cases were identified by the 4-chamber view and 5 by an abnormal 3-vessel view. The sensitivity of the 4-chamber view alone was 65.6%, and the specificity was 99.9%. The sensitivity of the combination of the 4-chamber view and 3-vessel view was 81.3%, and the specificity was 99.9%.

CONCLUSIONS

The 3-vessel view is a reliable and easy method to be used in a routine antenatal clinic along with the 4-chamber view.

Four-dimensional fetal echocardiography with spatiotemporal image correlation (STIC): A systematic study of standard cardiac views assessed by different observers

OBJECTIVE

To test the agreement between observers and reproducibility of a technique to display standard cardiac views of the left and right ventricular outflow tracts from four-dimensional volume datasets acquired with Spatiotemporal Image Correlation (STIC).

METHODS

A technique was developed to obtain dynamic multiplanar images of the left ventricular outflow tract (LVOT) and right ventricular outflow tract (RVOT) from volume datasets acquired with STIC. Volume datasets were acquired from fetuses with normal cardiac anatomy. Twenty volume datasets of satisfactory quality were pre-selected by one investigator. The data was randomly assigned for a blinded review by two independent observers with previous experience in fetal echocardiography. Only one volume dataset was used for each fetus. After a training session, the observers obtained standardized cardiac views of the LVOT and RVOT, which were scored on a scale of 1 to 5, based on diagnostic value and image quality (1=unacceptable, 2=marginal, 3=acceptable, 4=good, and 5=excellent). Median scores and interquartile range, as well as inter- and intraobserver agreement were calculated for each view.

RESULTS

The mean menstrual age at the time of volume acquisition was 25.5+/-4.5 weeks. Median scores (interquartile range) for LVOT images, obtained by the first and second observers, were 3.5 (2.25-5.00) and 4 (3.00-5.00), respectively. The median scores (interquartile range) for RVOT images obtained by the first and second observers were 3 (3.00-5.00) and 3 (2.00-4.00), respectively. The interobserver intraclass correlation coefficient for the LVOT was 0.693 (95% CI 0.380-0.822), and 0.696 (95% CI 0.382-0.866) for the RVOT. For the intraobserver agreement analysis, observer 1 gave higher scores to the LVOT the second time the volumes were analyzed [LVOT: 3.50 (2.25-5.00) vs. 5.00 (4.00-5.00, p=0.008)].

CONCLUSION

STIC can be reproducibly used to evaluate fetal cardiac outflow tracts by independent examiners. Slightly better image quality rating scores during the intraobserver variability trial suggests the presence of a learning curve for the manipulation and analysis of volume data obtained by STIC.