Fetal echocardiography at the time of the nuchal translucency scan

Live-Birth Incidence of Isolated D-Transposition of Great Arteries-The Shift in Trends Due to Early Diagnosis

This is a single tertiary population-based study conducted at a center in southwest Romania. We retrospectively compared data obtained in two periods: January 2008-December 2013 and January 2018-December 2023. The global incidence of the transposition of great arteries in terminated cases, in addition to those resulting in live-born pregnancies, remained almost constant. The live-birth incidence decreased. The median gestational age at diagnosis decreased from 29.3 gestational weeks (mean 25.4) to 13.4 weeks (mean 17.2). The second trimester and the overall detection rate in the prenatal period did not significantly change, but the increase was statistically significant in the first trimester. The proportion of terminated pregnancies in fetuses diagnosed with the transposition of great arteries significantly increased (14.28% to 75%, p = 0.019).

Clinical implementation of first trimester screening for congenital heart defects

OBJECTIVE

To examine the feasibility and performance of implementing a standardized fetal cardiac scan at the time of a routine first-trimester ultrasound scan.

METHOD

A retrospective, single-center study in an unselected population between March 2021 and July 2022. A standardized cardiac scan protocol consisting of a four-chamber and 3-vessel trachea view with color Doppler was implemented as part of the routine first-trimester scan. Sonographers were asked to categorize the fetal heart anatomy. Data were stratified into two groups based on the possibility of evaluating the fetal heart. The influence of maternal and fetal characteristics and the detection of major congenital heart disease were investigated.

RESULTS

A total of 5083 fetuses were included. The fetal heart evaluation was completed in 84.9%. The proportion of successful scans increased throughout the study period from 76% in the first month to 92% in the last month. High maternal body mass index and early gestational age at scan significantly decreased the feasibility. The first-trimester detection of major congenital heart defects was 7/16, of which four cases were identified by the cardiac scan protocol with no false-positive cases.

CONCLUSION

First-trimester evaluation of the fetal heart by a standardized scan protocol is feasible to implement in daily practice. It can contribute to the earlier detection of congenital heart defects at a very low false positive rate.

Nuchal Translucency and Congenital Heart Defects

Nuchal translucency comprises a temporary accumulation of fluid in the subcutaneous tissue on the back of a fetus's neck, which accompanies the crown-rump length and is observed through an ultrasound performed between 11 and 13 weeks + 6 days gestation. Nuchal translucency is considered to be above normal when values are higher than the 95th/99th percentile or equal to or higher than 2.5/3.5 mm. The first connection between increased nuchal translucency and the presence of congenital heart defects is described in the study of Hyett et al., who observed that they are directly proportional. Since that time, several studies have been conducted to understand if nuchal translucency measurements can be used for congenital heart defect screening in euploid fetuses. However, there is great variability in the estimated nuchal translucency cutoff values for congenital heart defect detection. The purpose of this review was to understand how increased nuchal translucency values and congenital heart defects are related and to identify which of these defects are more frequently associated with an increase in these values.

E-Health: A Game Changer in Fetal and Neonatal Cardiology?

Technological advancements have greatly impacted the healthcare industry, including the integration of e-health in pediatric cardiology. The use of telemedicine, mobile health applications, and electronic health records have demonstrated a significant potential to improve patient outcomes, reduce healthcare costs, and enhance the quality of care. Telemedicine provides a useful tool for remote clinics, follow-up visits, and monitoring for infants with congenital heart disease, while mobile health applications enhance patient and parents' education, medication compliance, and in some instances, remote monitoring of vital signs. Despite the benefits of e-health, there are potential limitations and challenges, such as issues related to availability, cost-effectiveness, data privacy and security, and the potential ethical, legal, and social implications of e-health interventions. In this review, we aim to highlight the current application and perspectives of e-health in the field of fetal and neonatal cardiology, including expert parents' opinions.

Learning deep architectures for the interpretation of first-trimester fetal echocardiography (LIFE) - a study protocol for developing an automated intelligent decision support system for early fetal echocardiography

BACKGROUND

Congenital Heart Disease represents the most frequent fetal malformation. The lack of prenatal identification of congenital heart defects can have adverse consequences for the neonate, while a correct prenatal diagnosis of specific cardiac anomalies improves neonatal care neurologic and surgery outcomes. Sonographers perform prenatal diagnosis manually during the first or second-trimester scan, but the reported detection rates are low. This project's primary objective is to develop an Intelligent Decision Support System that uses two-dimensional video files of cardiac sweeps obtained during the standard first-trimester fetal echocardiography (FE) to signal the presence/absence of previously learned key features.

METHODS

The cross-sectional study will be divided into a training part of the machine learning approaches and the testing phase on previously unseen frames and eventually on actual video scans. Pregnant women in their 12-13 + 6 weeks of gestation admitted for routine first-trimester anomaly scan will be consecutively included in a two-year study, depending on the availability of the experienced sonographers in early fetal cardiac imaging involved in this research. The Data Science / IT department (DSIT) will process the key planes identified by the sonographers in the two- dimensional heart cine loop sweeps: four-chamber view, left and right ventricular outflow tracts, three vessels, and trachea view. The frames will be grouped into the classes representing the plane views, and then different state-of-the- art deep-learning (DL) pre-trained algorithms will be tested on the data set. The sonographers will validate all the intermediary findings at the frame level and the meaningfulness of the video labeling.

DISCUSSION

FE is feasible and efficient during the first trimester. Still, the continuous training process is impaired by the lack of specialists or their limited availability. Therefore, in our study design, the sonographer benefits from a second opinion provided by the developed software, which may be very helpful, especially if a more experienced colleague is unavailable. In addition, the software may be implemented on the ultrasound device so that the process could take place during the live examination.

TRIAL REGISTRATION

The study is registered under the name "Learning deep architectures for the Interpretation of Fetal Echocardiography (LIFE)", project number 408PED/2020, project code PN-III-P2-2.1-PED-2019.

TRIAL REGISTRATION

ClinicalTrials.gov , unique identifying number NCT05090306, date of registration 30.10.2020.

First-trimester ultrasound detection of fetal heart anomalies: systematic review and meta-analysis

OBJECTIVES

To determine the diagnostic accuracy of ultrasound at 11-14 weeks' gestation in the detection of fetal cardiac abnormalities and to evaluate factors that impact the detection rate.

METHODS

This was a systematic review of studies evaluating the diagnostic accuracy of ultrasound in the detection of fetal cardiac anomalies at 11-14 weeks' gestation, performed by two independent reviewers. An electronic search of four databases (MEDLINE, EMBASE, Web of Science Core Collection and The Cochrane Library) was conducted for studies published between January 1998 and July 2020. Prospective and retrospective studies evaluating pregnancies at any prior level of risk and in any healthcare setting were eligible for inclusion. The reference standard used was the detection of a cardiac abnormality on postnatal or postmortem examination. Data were extracted from the included studies to populate 2 × 2 tables. Meta-analysis was performed using a random-effects model in order to determine the performance of first-trimester ultrasound in the detection of major cardiac abnormalities overall and of individual types of cardiac abnormality. Data were analyzed separately for high-risk and non-high-risk populations. Preplanned secondary analyses were conducted in order to assess factors that may impact screening performance, including the imaging protocol used for cardiac assessment (including the use of color-flow Doppler), ultrasound modality, year of publication and the index of sonographer suspicion at the time of the scan. Risk of bias and quality assessment were undertaken for all included studies using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool.

RESULTS

The electronic search yielded 4108 citations. Following review of titles and abstracts, 223 publications underwent full-text review, of which 63 studies, reporting on 328 262 fetuses, were selected for inclusion in the meta-analysis. In the non-high-risk population (45 studies, 306 872 fetuses), 1445 major cardiac anomalies were identified (prevalence, 0.41% (95% CI, 0.39-0.43%)). Of these, 767 were detected on first-trimester ultrasound examination of the heart and 678 were not detected. First-trimester ultrasound had a pooled sensitivity of 55.80% (95% CI, 45.87-65.50%), specificity of 99.98% (95% CI, 99.97-99.99%) and positive predictive value of 94.85% (95% CI, 91.63-97.32%) in the non-high-risk population. The cases diagnosed in the first trimester represented 63.67% (95% CI, 54.35-72.49%) of all antenatally diagnosed major cardiac abnormalities in the non-high-risk population. In the high-risk population (18 studies, 21 390 fetuses), 480 major cardiac anomalies were identified (prevalence, 1.36% (95% CI, 1.20-1.52%)). Of these, 338 were detected on first-trimester ultrasound examination and 142 were not detected. First-trimester ultrasound had a pooled sensitivity of 67.74% (95% CI, 55.25-79.06%), specificity of 99.75% (95% CI, 99.47-99.92%) and positive predictive value of 94.22% (95% CI, 90.22-97.22%) in the high-risk population. The cases diagnosed in the first trimester represented 79.86% (95% CI, 69.89-88.25%) of all antenatally diagnosed major cardiac abnormalities in the high-risk population. The imaging protocol used for examination was found to have an important impact on screening performance in both populations (P < 0.0001), with a significantly higher detection rate observed in studies using at least one outflow-tract view or color-flow Doppler imaging (both P < 0.0001). Different types of cardiac anomaly were not equally amenable to detection on first-trimester ultrasound.

CONCLUSIONS

First-trimester ultrasound examination of the fetal heart allows identification of over half of fetuses affected by major cardiac pathology. Future first-trimester screening programs should follow structured anatomical assessment protocols and consider the introduction of outflow-tract views and color-flow Doppler imaging, as this would improve detection rates of fetal cardiac pathology. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Feasibility and Accuracy of Early Fetal Echocardiography Performed at 13+0-13+6 Weeks in a Population with Low and High Body Mass Index: a Prospective Study

PURPOSE

The earlier the detection and diagnosis of congenital heart diseases (CHD), the greater the clinical benefit; however, early fetal cardiac examination can be a challenge. The aim of our study is to demonstrate that the fetal cardiac examination at 13⁺⁰-13⁺⁶ weeks can be as adequately assessed as the examination performed at 16 weeks in patients with low and high body mass index (BMI).

METHODS

The study was a prospective observational cohort study. One hundred pregnant women at low risk of congenital heart anomalies were divided into two groups: 49 women with low BMI (<25) and 51 women with high BMI (≥ 25). A complete fetal cardiac scan was performed on each patient at 13⁺⁰-13⁺⁶ weeks, via the transvaginal and transabdominal approaches, and at 16 weeks by the transabdominal approach.

RESULTS

The examination at 13⁺⁰-13⁺⁶ weeks was adequately assessed in at least one of the two routes in 97 patients, as opposed to 87 patients at 16 weeks. A significantly higher adequate assessment rate was obtained at 13⁺⁰-13⁺⁶ weeks than at 16 weeks (p=0.017). The transvaginal approach showed the best resolution of the three examinations in 42% of women with BMI ≥35. No CHD were overlooked.

CONCLUSIONS

Early fetal echocardiography is feasible and accurate at 13⁺⁰-13⁺⁶ weeks. Within patients with high BMI, early fetal echocardiography may be performed two weeks in advance, since it allows visualization of the fetal heart through the transvaginal route with a higher resolution in a large number of women, which is not feasible at 16 weeks.

Performance of First-Trimester Fetal Echocardiography in Diagnosing Fetal Heart Defects: Meta-analysis and Systematic Review

OBJECTIVES

Early fetal echocardiography is becoming increasing common during the nuchal translucency scan period. The aim of this meta-analysis was to assess the accuracy of first-trimester fetal echocardiography in diagnosing congenital heart defects (CHDs).

METHODS

The databases of PubMed, Embase, the Cochrane Library, and the Cumulative Index to Nursing and Allied Health Literature were systematically searched for the candidate articles, and the references of included studies were also examined. We recorded the characteristics of the included studies and assessed the quality of each study by the Quality Assessment of Diagnostic Accuracy Studies tool. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) were calculated with Meta-Disc version 1.4 software (Ramón y Cajal Hospital, Madrid, Spain). We also evaluated the publication bias by using Stata version 12.0 software (StataCorp, College Station, TX).

RESULTS

This meta-analysis included 18 studies with 26,201 fetal hearts. The overall pooled sensitivity, specificity, PLR, and NLR were 0.750, 0.999, 392.95, and 0.277, respectively. The DOR and AUC were 1736.0 and 0.9331. The pooled sensitivity, specificity, PLR, NLR, DOR, and AUC for major CHDs were 0.838, 1.000, 725.69, 0.203, 5084.8, and 0.9617.

CONCLUSIONS

First-trimester fetal echocardiography had high value in diagnosing CHDs, especially major CHDs.

Fetal heart examination at the time of 13 weeks scan: a 5 years' prospective study

Objective To evaluate our ability in classifying the fetal heart as normal or abnormal during the 1st trimester scan through fetal cardiac examination and determining the best time for this examination. Methods This was a prospective study performed on 3240 pregnant women to examine the fetal heart. Four chambers view and ventricular outflow tracts were mainly examined during the scan. We used grayscale and color mapping in the diagnosis. Color Doppler was used if additional information was needed, and all patients were rescanned during the 2nd trimester to confirm or negate our diagnosis. Results The cardiac findings were normal at both scans in 3108 pregnancies. The same cardiac abnormality was detected at both scans in 79 cases. In 36 cases there was false-positive diagnosis at the early scan; in 20 of these cases, there were mildly abnormal functional findings early in pregnancy with no abnormality found later. In 17 fetuses, there was discordance between the early and later diagnosis due to missed or incorrect diagnoses. The best time to do fetal heart examination during 1st trimester is between 13 and 13 + 6 weeks. Conclusion A high degree of accuracy in the identification of congenital heart disease (CHD) can be achieved by a 1st trimester fetal echocardiography.

"Y Sign" at the Level of the 3-Vessel and Trachea View: An Effective Fetal Marker of Aortic Dextroposition Anomalies in the First Trimester

OBJECTIVES

The "Y sign" at the level of the 3-vessel and trachea view corresponds to thinning of main pulmonary artery and arterial duct and a dilated transverse aortic arch. The purpose of this study was to evaluate the Y sign for the diagnosis of aortic dextroposition anomalies at the time of the first-trimester scan and to assess the screening performance of only the Y sign, only abnormal left axis deviation (axis sign), and their combination for the diagnosis of aortic dextroposition anomalies.

METHODS

A prospective evaluation of 6025 pregnant women undergoing first-trimester ultrasonography was conducted. The cardiac axis was measured in all examined patients and considered abnormal (positive axis sign) at greater than 57 °. The frequency of the Y sign and the axis sign was assessed for this population, and their screening performance for the diagnosis of aortic dextroposition anomalies was calculated.

RESULTS

A total of 5775 patients fulfilled the inclusion criteria. Aortic dextroposition anomalies were diagnosed in 17 cases (tetralogy of Fallot in 8 and Fallot-like double-outlet right ventricle in 9). The Y sign was found in 18 of 5775 (0.3%) fetuses examined, of which 7 of 18 were confirmed with tetralogy of Fallot, 9 of 18 with a Fallot-like double-outlet right ventricle, and 2 of 18 with pulmonary stenosis. A positive axis sign of greater than 57 ° was found in 20 fetuses, including 4 with normal heart anatomy. The sensitivity values of the Y sign, the axis sign, and their combination were 94%, 76%, and 94%, respectively.

CONCLUSIONS

Visualization of the Y sign should increase the suspicion of aortic dextroposition anomalies in the late first trimester. The screening performance of the Y sign alone and in combination with an abnormal cardiac axis was high and may aid in the early diagnosis of aortic dextroposition anomalies in the fetus.

Anomalous Pulmonary Venous Return: Insights Into Prenatal Detection

OBJECTIVES

To review all cases of total anomalous pulmonary venous return (TAPVR) or partial anomalous pulmonary venous return (PAPVR) identified prenatally or postnatally at a single institution and to identify factors that may lead to a correct or missed diagnosis in both high- and low-risk fetuses on screening examinations.

METHODS

Fetal images from 16 cases of prenatally or postnatally diagnosed T/PAPVR were retrospectively reviewed to analyze factors that influenced interpretations and diagnoses.

RESULTS

Sixteen diagnoses of T/PAPVR were made, with a final number of 10 confirmed cases, 1 of which was PAPVR. Ten fetuses with a presumptive diagnosis of T/PAPVR before delivery were at an average gestational age of 24.7 weeks, with 5 cases diagnosed postnatally. None of the diagnoses of isolated TAPVR were made during a screening examination. Twelve of the pregnancies were complicated by complex cardiac defects, including 6 with heterotaxy syndromes. Of the 5 abnormal cases identified in the postpartum period, 3 had isolated TAPVR. In the 3 patients with isolated defects, prenatal echocardiography was not performed; the anatomy scan interpretations were confounded by multiple factors. In retrospect, there was no obvious sonographic evidence of TAPVR in these patients; however, color flow Doppler imaging of the pulmonary veins was not performed on any of them.

CONCLUSIONS

Although fetal echocardiography has improved the overall detection of TAPVR or PAPVR, this abnormality continues to elude prenatal diagnosis during screening in both low- and high-risk patients. We hypothesize that the use of color flow Doppler imaging in the 4-chamber view may assist in diagnosing TAPVR in screening low-risk patients, especially in those with difficult scans.

Safety Indices during Fetal Echocardiography at the Time of First-Trimester Scan Are Machine Dependent

The aim of our study was to evaluate the thermal index (TI) and mechanical index (MI), during the assessment of the fetal heart at the time of first-trimester scan, with different ultrasound machines. This was part of an observational study conducted in patients undergoing routine first-trimester screening. Cases were examined with Voluson E8 or 730Pro scanners using 2–8 MHz transabdominal probes. TI and MI were retrieved from the saved displays while in gray mode, color flow mapping and pulsed-wave (PW) Doppler examinations of the fetal heart and also from the ductus venosus (DV) assessment. We evaluated 552 fetal cardiac examinations, 303 (55%) performed with Voluson E8 and 249 (45%) with Voluson 730Pro ultrasound machines. The gray-scale exam of the heart and the PW Doppler DV assessment had TI values significantly lower for the Voluson E8 group (median, 0.04 vs. 0.2 and 0.1 vs. 0.2, respectively). The MI values from gray-scale and color flow mapping of the heart were significantly lower (median, 0.6 vs, 1.2 and 0.7 vs. 1) and for PW Doppler exam of the tricuspid flow were significantly higher (median 0.4 vs. 0.2) in the Voluson E8 group. The TI values from Doppler examinations of the heart, either color flow or PW imaging and MI values from DV assessment were not significantly different between the two groups. A different (newer) generation of ultrasound equipment provides lower or at least the same safety indices for most of the first-trimester heart examinations.

In vivo application of short-lag spatial coherence and harmonic spatial coherence imaging in fetal ultrasound

Fetal scanning is one of the most common applications of ultrasound imaging and serves as a source of vital information about maternal and fetal health. Visualization of clinically relevant structures, however, can be severely compromised in difficult-to-image patients due to poor resolution and the presence of high levels of acoustical noise or clutter. We have developed novel coherence-based beamforming methods called Short-Lag Spatial Coherence (SLSC) imaging and Harmonic Spatial Coherence imaging (HSCI), and applied them to suppress the effects of clutter in fetal imaging. This method is used to create images of the spatial coherence of the backscattered ultrasound as opposed to images of echo magnitude. We present the results of a patient study to assess the benefits of coherence-based beamforming in the context of first trimester fetal exams. Matched fundamental B-mode, SLSC, harmonic B-mode, and HSCI images were generated using raw radio frequency data collected on 11 volunteers in the first trimester of pregnancy. The images were compared for qualitative differences in image texture and target conspicuity as well as using quantitative imaging metrics such as signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and contrast. SLSC and HSCI showed statistically significant improvements across all imaging metrics compared with B-mode and harmonic B-mode, respectively. These improvements were greatest for poor quality B-mode images where contrast of anechoic targets was improved from 15 dB in fundamental B-mode to 27 dB in SLSC and 17 dB in harmonic B-mode to 30 dB in HSCI. CNR improved from 1.4 to 2.5 in the fundamental images and 1.4 to 3.1 in the harmonic case. These results exhibit the potential of coherence-based beamforming to improve image quality and target detectability, especially in high noise environments.

Prenatal detection of congenital heart defects at the 11- to 13-week scan using a simple color Doppler protocol including the 4-chamber and 3-vessel and trachea views

OBJECTIVES

The first goal of this study was to analyze the diagnostic performance of the 4-chamber view, 3-vessel and trachea view, and their combination in color mapping during early cardiac evaluations for selecting cases suspicious of congenital heart defects. The second goal was to describe the most common abnormal flow patterns at the levels of the 4-chamber and 3-vessel and trachea views in the late first trimester.

METHODS

We conducted a prospective observational study in which a simple cardiac sonographic protocol was applied in fetuses at gestational ages of 11 weeks to 13 weeks 6 days.

RESULTS

A total of 1084 patients with known postnatal or autopsy findings were included in the study. The median maternal age was 32.3 years (range, 27-40 years). The median crown-rump length was 62.2 mm (range, 45-84 mm). Overall, there were 35 cases with a confirmed congenital heart defect (3.22%), including 16 accompanied by aneuploidy. We found that our simple first-trimester cardiac protocol was an effective screening method for congenital heart defects. The most effective approach of the 3 evaluated by us was the combined application of the 4-chamber and 3-vessel and trachea views in color mapping compared to the 4-chamber and 3-vessel and trachea views alone. We defined the most common ventricular inflow patterns and the V sign. The technique we used was simple and easy to reproduce.

CONCLUSIONS

We confirmed that evaluation by two basic cardiac views allows for selection of most cases with a univentricular heart, atrioventricular septal defects, coarctation of the aorta, pulmonary stenosis, pulmonary atresia, and conotruncal defects.

Acoustic output measured by thermal and mechanical indices during fetal echocardiography at the time of the first trimester scan

We measured acoustic output, expressed as the thermal index (TI) and mechanical index (MI), during fetal echocardiography at the time of the first trimester scan. TI and MI were retrieved from the saved displays during gray-mode, high-definition color flow Doppler and pulsed-wave Doppler (tricuspid flow) ultrasound examinations of the fetal heart and from the ductus venosus assessment. A total of 399 fetal cardiac examinations were evaluated. There was a significant increase in TI values from B-mode studies (0.07 ± 0.04 [mean ± SD]) to color flow mapping (0.2 ± 0.0) and pulsed-wave Doppler studies (0.36 ± 0.05). The TI from ductus venosus assessment (0.1 ± 0.01) was significantly lower than those from Doppler examinations of the heart. MI values from B-mode scans (0.65 ± 0.12) and color flow mapping (0.71 ± 0.11) were comparable, although different, and both values were higher than those from pulsed-wave Doppler tricuspid evaluation (0.39 ± 0.03). There were no differences in MI values from power Doppler assessment between the tricuspid flow and ductus venosus. Safety indices were remarkably stable and were largely constant, especially for color Doppler (TI), tricuspid flow (MI) and ductus venosus assessment (TI, MI). We acquired satisfactory Doppler images and/or signals at acoustic levels that were lower than the actual recommendations and never reached a TI of 0.5.

Factors affecting the feasibility of routine first-trimester fetal echocardiography

OBJECTIVES

The purpose of our study was to assess the factors that may improve the feasibility of routine fetal echocardiography at the time of the first-trimester scan.

METHODS

In this prospective study, we included 616 healthy singleton fetuses. Examinations were performed transabdominally by a single sonographer at the beginning of his training in first-trimester screening. The fetal heart was examined by high-definition color Doppler imaging to obtain the 4-chamber view, right and left ventricular outflow tracts, and 3-vessel and trachea view. Logistic regression was used to investigate the effect on the ability to visualize different cardiac structures.

RESULTS

The frequency of successful heart examinations increased significantly with the number of scans performed (P < .05). The sonographer needed 180 examinations before he could successfully examine the heart in at least 80% of cases. Significant factors that increased the probability of adequate echocardiography were the length of the heart examination and the experience of the sonographer (P< .05) but not transducer-heart distance, maternal body mass index, fetal crown-rump length, placenta interposition, or restrictive fetal position. Visualization of the left ventricular outflow tract could be improved by increasing the experience of the sonographer and decreasing the transducer-heart distance. Also, visualization of the 3-vessel and trachea view depended on the length of the heart examination, the experience of the sonographer, an anterior position of the placenta, and a restrictive fetal position.

CONCLUSIONS

Competence in color flow mapping assessment of the fetal heart at gestational ages of 11 weeks to 13 weeks 6 days is achieved only after extensive supervised training.

Postmortem microcomputed tomography (micro-CT) of small fetuses and hearts

OBJECTIVE

To assess the feasibility and utility of contrast-enhanced microcomputed tomography (micro-CT) for identifying structural anomalies in ex-vivo first- and second-trimester human fetuses and isolated fetal hearts.

METHODS

Radiopaque iodine staining and micro-CT scanning protocols were first developed in rodent studies and then used to examine routinely fixed whole human fetuses (n = 7, weight 0.1-90 g, gestational age, 7-17 weeks) and isolated fetal hearts (n = 14, weight 0.1-5.2 g, gestational age, 11-22 weeks). Samples were scanned using an isotropic resolution of 18 (and, if necessary, 9 or 35) µm and findings were interpreted jointly by four fetal pathologists, a fetal cardiologist and a radiologist. Samples with gestational ages ≥ 13 weeks also underwent conventional autopsy or dissection.

RESULTS

Micro-CT identified all anatomical structures and abnormalities documented by the macroscopic examination. In all seven cases involving fetuses ≤ 13 weeks (four fetuses, three isolated hearts), micro-CT excluded the presence of structural anomalies. In the remaining 14 cases, it provided all the information obtained with invasive autopsy or dissection and in seven of the 14 (two fetuses, five isolated hearts) it furnished additional diagnostic details.

CONCLUSIONS

This pilot study confirms the feasibility of postmortem contrast-enhanced micro-CT assessment of structural anomalies in whole small fetuses and fetal hearts. Further study is needed to confirm our findings, particularly in whole fetuses, and to define the extent to which this virtual examination might be used instead of conventional invasive autopsy.

Who should be referred? An evaluation of referral indications for fetal echocardiography in the detection of structural congenital heart disease

Although fetal echocardiography is a useful tool for earlier detection of congenital heart disease (CHD), no clear, evidence-based appropriate use criteria exist. This study aimed to determine those referral indications most predictive of CHD. A retrospective cohort study of fetal echocardiograms was conducted at a single tertiary care center. Binomial proportion tests were used to compare likelihoods of structural CHD detection based on primary indication with the general population prevalence of 0.8%. Fetal echocardiograms of 2,380 pregnancies were performed, with CHD detected in 29.3% of these pregnancies. Patients referred for suspected CHD on screening ultrasound had the highest prevalence of CHD. Of the women without a history of cardiac anomalies shown on screening ultrasound, those with extracardiac anomalies or known chromosomal abnormalities had the highest prevalence of CHD. Screening ultrasound currently is the most useful method for determining who should be referred for fetal echocardiography, with a high prevalence of CHD found. For women with normal cardiac screening ultrasound results, fetal factors such as extracardiac anomalies and chromosomal abnormalities are more predictive of CHD than maternal or familial factors.

Simplified first-trimester fetal cardiac screening (four chamber view and ventricular outflow tracts) in a low-risk population

OBJECTIVES

Our aim was to assess the accuracy of a simplified fetal cardiac study, inclusive of four-chamber view (4CV) and ventricular outflow tracts, performed during the 11-14 week screening by well-trained obstetricians to detect congenital heart diseases (CHDs).

METHODS

A transabdominal ultrasound was performed on 4820 singleton pregnant women at 11-14 weeks to visualize the visceral site, the 4CV, and the outflow tracts. Neonatal outcomes were recorded 6 and 12 months after birth.

RESULTS

Among the 4820 patients reviewed, 790 were excluded because of loss at prenatal or postnatal follow-up (649 cases), or inability to obtain adequate first-trimester sonographic cardiac evaluation (141 cases). Among the 4030 included cases, 32 CHD cases were detected (20 major and 12 minor); 18 of the major (90%) and five of the minor (42%) were detected or suspected in the first trimester, one major and six minor in the second trimester, and one major and one minor only after birth.

CONCLUSIONS

A simplified protocol is an effective tool to screen for CHD at 11-14 weeks.

Accuracy of ultrasonography at 11-14 weeks of gestation for detection of fetal structural anomalies: a systematic review

OBJECTIVE

To review the literature concerning the efficacy of early ultrasonography (at 11-14 weeks of gestation) to identify fetal malformations.

DATA SOURCES

A search in PubMed, MEDLINE, Embase, Cochrane Library, and ClinicalTrials.gov was performed (January 2000 to December 2012). Keywords were: fetal anatomy, fetal echocardiography, nuchal translucency, fetal structural anomalies, fetal malformations, prenatal diagnosis, prenatal screening, and first-trimester ultrasonography.

METHODS OF STUDY SELECTION

Inclusion criteria were: fetal anatomy examination at early ultrasonography and diagnosis of fetal malformations confirmed by postnatal or postmortem examination. Data abstracted were: sample size, location of structural defect, ultrasound modality, presence of multiple defects, and study population. Pooled detection rate was calculated for each malformation and compared with χ. Differences were considered statistically significant if P<.05.

TABULATION, INTEGRATION, AND RESULTS

From 1,203 articles, 19 were included. Overall, we pooled 78,002 fetuses undergoing ultrasonography at 11-14 weeks, of which 996 were malformed, leading to prevalence of malformation of 12 per 1,000. The overall detection rate was 472 of 957 (51%). The highest detection rate was achieved for neck anomalies (92%), whereas limbs (34%), face (34%), and genitourinary anomalies (34%) were associated with the lowest detection rate. At 14 weeks of gestation or less, fetal echocardiography detected 53% of congenital heart disease compared with 43% by complete scan (P=.040). The use of Doppler did not improve the detection rate for congenital heart defects (52% compared with 44%, respectively; P=.11). Multiple defects were identified more frequently than isolated malformations (60% compared with 44%; P=.005). The detection rate was higher combining transabdominal and transvaginal techniques (62%) than either abdominal (51%) or transvaginal (34%; P<.001). Detection rate was higher in women at high risk (65%) than unselected population (50% P=.001).

CONCLUSION

Because of the natural history of fetal defects and the late development of some organ systems, a number of fetal malformations remain undetected by early ultrasonography.

First trimester two- and four-dimensional cardiac scan: intra- and interobserver agreement, comparison between methods and benefits of color Doppler technique

OBJECTIVE

To evaluate intra- and interobserver agreement for first-trimester fetal cardiac structural assessment, using two-dimensional (2D) ultrasound (2D-US) and 4D-US (4D spatiotemporal image correlation (STIC) technology), to compare the methods and to assess the advantages of adding color Doppler to each technique.

METHODS

Digital videoclips (B-mode and color Doppler) and 4D-STIC volumes (gray-scale and color Doppler) from 632 pregnancies with normal fetal hearts were acquired and stored at the time of detailed first-trimester ultrasound examination. Later analysis on a randomized sample of 100 cases was performed, targeting 11 cardiac structures and features. We compared visualization of fetal heart parameters using 2D-US vs 4D-US and gray-scale vs color Doppler imaging.

RESULTS

STIC volumes were considered satisfactory (adequate visualization of at least 8/11 parameters) in 78% of cases and 2D-US acquisitions in 89% of cases. The intra- and interobserver agreement was good for both 2D and 4D methods (kappa > 0.6), and the percentage overall agreement was very high using both methods (95%). 2D- and 4D-US identification of the fetal cardiac parameters did not differ significantly. The differences between gray-scale and color Doppler imaging were statistically significant in identifying similar key cardiac parameters, for both 2D- and 4D-US (P < 0.05).

CONCLUSION

Both 2D and 4D methods for assessing first-trimester heart parameters are feasible and repeatable within and between observers. Color Doppler adds valuable information to both methods.

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.

Nuchal translucency and major congenital heart defects in fetuses with normal karyotype: a meta-analysis

OBJECTIVE

To pool published data regarding the sensitivity and specificity of nuchal translucency (NT) in the diagnosis of major congenital heart defects (CHDs) in fetuses with normal karyotype.

METHODS

MEDLINE and Scopus searches using combinations of the terms 'nuchal' and 'cardiac*' were complemented by perusal of references of the retrieved articles and an additional automated search using the 'search for related articles' function on PubMed. Only fetuses with normal karyotype and major CHDs were analyzed. Weighted estimates were made and summary receiver-operating characteristics curves were constructed.

RESULTS

The analysis included 20 studies (205 232 fetuses; 537 cases with major CHDs). The pooled sensitivity and specificity of NT > 95(th) centile for diagnosis of major CHDs was 44.4% (95% CI, 39.5-49.5) and 94.5% (95% CI, 94.4-94.6), respectively. The pooled sensitivity and specificity of NT > 99(th) centile was 19.5% (95% CI, 15.9-23.5) and 99.1% (95% CI, 99.1-99.2), respectively. For the subgroup of studies in which NT was measured by Fetal Medicine Foundation-certified operators, the pooled sensitivity and specificity of NT > 95(th) centile was 45.6% (95% CI, 39.6-51.7) and 94.7% (95% CI, 94.6-94.9), respectively. The corresponding estimates for NT > 99(th) centile were 21.0% (95%CI, 16.5-26.1) and 99.2% (95% CI, 99.2-99.3). The pooled positive likelihood ratio for NT > 99(th) centile was 30.5 (95% CI, 24.3-38.6). There was high across-studies heterogeneity for most estimates.

CONCLUSION

Approximately 44% of chromosomally normal fetuses with CHDs have NT > 95(th) centile and 20% have NT > 99(th) centile. However, there is high heterogeneity across studies, which largely remains even in subgroup analyses of studies of apparently similar design, potentially indicating the presence of some residual unidentified bias.

Improved detection rate of structural abnormalities in the first trimester using an extended examination protocol

OBJECTIVE

To assess the potential of first-trimester sonography in the detection of fetal abnormalities using an extended protocol that is achievable with reasonable resources of time, personnel and ultrasound equipment.

METHODS

This was a prospective two-center 2-year study of 5472 consecutive unselected pregnant women examined at 12 to 13 + 6 gestational weeks. Women were examined using an extended morphogenetic ultrasound protocol that, in addition to the basic evaluation, involved a color Doppler cardiac sweep and identification of early contingent markers for major abnormalities.

RESULTS

The prevalence of lethal and severe malformations was 1.39%. The first-trimester scan identified 40.6% of the cases detected overall and 76.3% of major structural defects. The first-trimester detection rate (DR) for major congenital heart disease (either isolated or associated with extracardiac abnormalities) was 90% and that for major central nervous system anomalies was 69.5%. In fetuses with increased nuchal translucency (NT), the first-trimester DR for major anomalies was 96%, and in fetuses with normal NT it was 66.7%. Most (67.1%) cases with major abnormalities presented with normal NT.

CONCLUSIONS

A detailed first-trimester anomaly scan using an extended protocol is an efficient screening method to detect major fetal structural abnormalities in low-risk pregnancies. It is feasible at 12 to 13 + 6 weeks with ultrasound equipment and personnel already used for routine first-trimester screening. Rate of detection of severe malformations is greater in early- than in mid-pregnancy and on postnatal evaluation. Early heart investigation could be improved by an extended protocol involving use of color Doppler.

Postmortem examination of human fetal hearts at or below 20 weeks' gestation: a comparison of high-field MRI at 9.4 T with lower-field MRI magnets and stereomicroscopic autopsy

OBJECTIVES

To compare the diagnostic usefulness of high-field with low-field magnetic resonance imaging (MRI) and stereomicroscopic autopsy for examination of the heart in fetuses at or under 20 weeks' gestation.

METHODS

Prior to invasive stereomicroscopic autopsy, MRI scans at 9.4, 3.0 and 1.5 T were performed on 24 fetuses between 11 and 20 weeks' gestation, including 10 fetuses with cardiac abnormalities. The ability to visualize different heart structures was evaluated according to the different field strength MRI magnets used and gestational age at examination.

RESULTS

On 1.5- and 3.0-T MRI, only the heart situs and four-chamber view could be visualized consistently (in 75% or more of cases) when the fetus was beyond 16 weeks' gestation, but other heart structures could not be visualized for fetuses at any gestational age. In contrast, using high-field MRI at 9.4 T, the heart situs, four-chamber view and the outflow tracts could be visualized in all fetuses irrespective of gestational age. Using high-field MRI, the sensitivity for detecting an abnormality of the four-chamber view was 66.7% (95% CI, 30.1-92.1%) with a specificity of 80.0% (95% CI, 51.9-95.4%). For abnormalities of the outflow tracts, sensitivity was 75.0% (95% CI, 20.3-95.9%) and specificity 100.0% (95% CI, 83.3-100.0%). Eight fetuses out of 10 with congenital heart disease (CHD) were classified as having major CHD. High-field MRI at 9.4 T was able to identify seven out of the eight cases of major CHD.

CONCLUSION

High-field MRI at 9.4 T seems to be an acceptable alternative approach to invasive stereomicroscopic autopsy for fetuses with CHD at or below 20 weeks' gestation.

Diagnosis of tetralogy of Fallot and its variants in the late first and early second trimester: details of initial assessment and comparison with later fetal diagnosis

OBJECTIVE

We sought to evaluate the completeness of echocardiographic diagnosis of fetal tetralogy of Fallot (fTOF) at 12-17 weeks gestation, and compare assessment and clinical outcomes to diagnoses made at >17 weeks gestation.

METHODS

We identified all fTOF diagnoses made in our experience from 2003 to 2008. Referral indication, anatomic detail by echocardiography and pregnancy outcomes were compared between fetuses diagnosed at ≤ 17 weeks (Group I) and >17 weeks gestation (Group II). A 10-point scoring tool was applied retrospectively to the echocardiograms at initial diagnosis (1 point each was ascribed to visualization of right ventricular outflow obstruction, pulmonary valve, pulmonary arteries including dimensions, pulmonary arterial flow, systemic and pulmonary venous anatomy, atrioventricular valves, ductus arteriosus, ductus flow, aortic arch morphology, sidedness and flow).

RESULTS

There were 10 pregnancies in Group I (12-17 weeks) and 25 in Group II (mean gestation at diagnosis 23.5 ± 5.7). The most common reason for referral was extracardiac pathology in Group I (80%) and suspected fetal heart disease on obstetric ultrasound in Group II (64%). Transabdominal imaging was adequate in about half of Group I studies. Mean anatomic diagnosis score in Group I was 6.1(range 2.5-9) and Group II was 8.4 (range 6.5-10). Elective pregnancy termination occurred in 80% in Group I and 33% in Group II.

CONCLUSIONS

fTOF can be diagnosed in first and early second trimesters with detailed anatomic assessment possible in most. Referral indication and pregnancy outcome differ considerably between early and later prenatal diagnosis of fTOF.

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.

Virtual autopsy by computed tomographic angiography of the fetal heart: a feasibility study

OBJECTIVE

To determine the feasibility of postmortem computed tomographic (pm-CT) angiography for fetal heart evaluation.

METHODS

Following termination of pregnancy (TOP) or intrauterine fetal death (IUFD) beyond 18 weeks' gestation, 33 fetuses were examined by pm-CT; in eight contrast medium was injected through the umbilical cord and in 25 contrast medium was injected directly into the heart. Logistic regression analysis was used to investigate the effect on the ability to visualize cardiac structures on pm-CT angiography of gestational age at TOP or delivery following IUFD, the time delay between fetal death and examination, the technique used for contrast-medium injection, the presence of cardiac abnormalities and whether or not there was IUFD. The diagnostic accuracy of pm-CT angiography for the evaluation of fetal cardiac structures was also evaluated.

RESULTS

Cardiac anatomy including heart situs, the four-chamber view and great vessels could be visualized on pm-CT angiography in 29 out of 33 fetuses (87.9%). Logistic regression analysis showed that the ability to visualize cardiac structures on pm-CT angiography was positively correlated only with contrast medium injected directly into the heart. Twenty-five out of the 33 fetuses underwent conventional autopsy. There were five cases with suspected major cardiac abnormality at prenatal ultrasound and one with a minor cardiac abnormality. In one of these cases, severe leakage into the pleural cavity did not allow for visualization of any heart structure on pm-CT angiography and in another invasive autopsy was declined. In two of the remaining four cases, the findings on pm-CT angiography and invasive autopsy were in agreement, while in two a ventricular septal defect was found on invasive autopsy but not on pm-CT. None of the 27 cases with normal hearts was falsely classified as abnormal using pm-CT angiography.

CONCLUSION

Pm-CT angiography by direct injection into the heart seems to be a feasible method for its evaluation. The extent to which such a technique could be used for the evaluation of congenital heart disease as an alternative to classical postmortem autopsy remains to be determined.

Comparison of ex-vivo high-resolution episcopic microscopy with in-vivo four-dimensional high-resolution transvaginal sonography of the first-trimester fetal heart

OBJECTIVE

To compare the capability of three-dimensional (3D) reconstructed images produced by high-resolution episcopic microscopy (HREM) with that of in-vivo four-dimensional high-resolution transvaginal sonography (4D-HRTVS) to discern morphological features of the first-trimester human fetal heart.

METHODS

This was a prospective study of fetal hearts between 9 and 14 weeks' gestation. For ex-vivo 3D analysis, 30 human fetal hearts (at 9 + 0 to 14 + 6 weeks) were retrieved from surgical terminations of pregnancy. The specimens were embedded in resin and episcopic ('block-face') imaging was used to obtain a digital volume dataset (HREM) using 3-micron slicing. 4D-HRTVS was performed in 28 separate pregnancies at 10 + 2 to 14 + 0 weeks using a Voluson E8 ultrasound machine with volumetric transvaginal RIC 6-12-MHz transducers. Heart volumes obtained by both methods were compared to assess their ability to demonstrate first-trimester cardiac morphology. Comparisons were made in the transverse and sagittal planes, and using volume rendering.

RESULTS

All hearts were structurally normal, although abdominal situs was not examined in the isolated hearts that underwent HREM. 4D-HRTVS demonstrated each of the complete five transverse cardiac views in 32-86% of cases. HREM showed four features unique to the first-trimester human heart: prominent atrial appendages, spiral ventricular arrangement, prominent coronary arteries and thickened arterial walls. 4D-HRTVS could demonstrate the first two, but ultrasound resolution was too poor to quantify wall thickness and demonstrate coronary arteries in the 3-5-mm diameter heart.

CONCLUSIONS

4D-HRTVS showed limited morphological features of the first-trimester fetal heart compared with HREM. HREM provides a gold standard of ex-vivo imaging against which developments in ultrasound resolution could be compared.

Use of a high-frequency linear transducer and MTI filtered color flow mapping in the assessment of fetal heart anatomy at the routine 11 to 13 + 6-week scan: a randomized trial

OBJECTIVE

To prospectively assess the contribution of a high-frequency linear transducer and of moving target indicator (MTI) filtered color flow mapping in the visualization of cardiac fetal anatomy at the routine 11 to 13 + 6-week scan.

METHODS

This was a cross-sectional prospective study, including 300 singleton fetuses at 11 to 13 + 6 weeks' gestation. Patients were randomized into four groups and a detailed fetal cardiac examination was conducted transabdominally using either a conventional curvilinear transducer, a conventional curvilinear transducer and MTI filtered color flow mapping, a high-frequency linear transducer or a high-frequency linear transducer and MTI filtered color flow mapping. Regression analysis was used to investigate the effect on the ability to visualize different cardiac structures of the following parameters: gestational age at ultrasound examination; fetal crown-rump length (CRL); maternal body mass index (BMI); transducer-heart distance; the technique used at ultrasound; and the position of the placenta.

RESULTS

The four-chamber view was visualized in 89.0% of fetuses and regression analysis showed this rate was correlated with CRL and the use of MTI filtered color flow mapping during ultrasonography, and inversely correlated with BMI and transducer-heart distance. Use of a conventional curvilinear transducer and MTI filtered color flow mapping allowed visualization of the four-chamber view in 97.3% of fetuses, while this was only possible in 84.0% of fetuses using a high-frequency linear transducer. The left and right outflow tracts were visualized in 62.3 and 57.7% of fetuses, respectively. Regression analysis showed that the ability to visualize the left or the right outflow tract was correlated with the use of MTI filtered color flow mapping during scanning and was inversely correlated with transducer-heart distance. The use of a conventional curvilinear transducer and MTI filtered color flow mapping allowed visualization of the left and right outflow tracts in 96.0 and 97.3% of fetuses, respectively, while this was only possible in 37.3 and 26.7% of fetuses using a high-frequency linear transducer.

CONCLUSIONS

During the routine 11 to 13 + 6-week scan, the use of MTI filtered color flow mapping but not of a high-frequency linear transducer, improves visualization of cardiac anatomy.

Learning curve and factors influencing the feasibility of performing fetal echocardiography at the time of the first-trimester scan

The purpose of this study was to assess the learning curve and factors influencing the feasibility of performing a complete fetal cardiac examination at the time of the first-trimester scan. The study included 103 fetuses undergoing first-trimester scans. The maternal body mass index, fetal crown-rump length, and 8 cardiac parameters were evaluated: 4-chamber view, tricuspid regurgitation, outflow tract crossover, bifurcating pulmonary artery, 3-vessel view, aortic arch, superior and inferior venae cavae on sagittal views, and Doppler images of the ductus venosus. All examinations were performed transabdominally by a single sonologist. The average times from the first to last cardiac images obtained were calculated. A complete examination was feasible in 55% of the cases: 15% of the first 52 and 94% of the last 51. Of the 8 cardiac parameters, 59.5% were seen in cases 1 to 21, 75.0% in cases 22 to 52, and 98.6% in the last 51 cases (P = .0001). The average times spent on the examinations increased from 4.37 to 9.3 minutes among the 3 groups (P = .032). There was no statistically significant influence for the crown-rump length (P = .899) or body mass index (P = .752). This study indicates that a fetal cardiac examination is feasible in the first trimester. Sonographer experience and the examination duration seem to be the most influential factors affecting the completeness of the examination.

Fetal echocardiography at 11-13 weeks by transabdominal high-frequency ultrasound

OBJECTIVES

To assess the accuracy of fetal echocardiography at 11-13 weeks performed by well-trained obstetricians using a high-frequency linear ultrasound transducer.

METHODS

Fetal echocardiography was performed by obstetricians immediately before chorionic villus sampling for fetal karyotyping at 11-13 weeks. Digital videoclips of the examination stored by the obstetrician were reviewed offline by a specialist fetal cardiologist.

RESULTS

The obstetrician suspected 95 (95%) of the 100 cardiac defects identified by the fetal cardiologist and made the correct diagnosis in 84 (84%) of these cases. In 54 fetuses, the defect was classified as major and in 46 it was minor. In 767 (86.6%) cases, the heart was normal and in 19 (2.1%) the views were inadequate for assessment of normality or abnormality. A subsequent second-trimester scan in the normal group identified major cardiac defects in four cases. Therefore, the first-trimester scan by the obstetricians and cardiologists identified 54 (93.1%) of the 58 major cardiac defects.

CONCLUSIONS

A well-trained obstetrician using high-resolution ultrasound equipment can assess the fetal heart at 11-13 weeks with a high degree of accuracy.

Role of first-trimester sonography in the diagnosis of aneuploidy and structural fetal anomalies

OBJECTIVE

We sought to determine the sensitivity of the first-trimester scan in the early diagnosis of aneuploidy and structural fetal anomalies in an unselected low-risk population.

METHODS

This was a retrospective chart review of all patients having first-trimester scans between 2002 and 2009. At our center, a survey of fetal anatomy is performed at the time of nuchal translucency assessment at 11 weeks to 13 weeks 6 days. A second-trimester scan is done at 20 to 23 weeks and a third-trimester scan at 32 to 35 weeks. Isolated sonographic findings of choroid plexus cysts and echogenic intracardiac foci were excluded. Lethal anomalies and those requiring immediate surgical intervention at birth were considered major structural anomalies. All scans were performed by a single sonologist certified by the Fetal Medicine Foundation. All neonates were examined at birth by a pediatrician.

RESULTS

Our study included 1370 fetuses. Six cases of aneuploidy (0.4%) were detected. The first-trimester scan detected 5 of 6 cases of aneuploidy (83%), confirmed by karyotype. There were 36 cases of structural fetal anomalies (2.6%); 20 (1.5%) were major anomalies. The first-trimester scan detected 16 of 36 (44%); 20 (56%) were identified by second- or third-trimester scans. The first-trimester scan detection rate for major structural anomalies was 14 of 20 (70%). The 5 that were missed by the first-trimester scan were detected by a second-trimester scan.

CONCLUSIONS

Our study emphasizes the importance of the first-trimester scan in the early detection of aneuploidy and structural fetal anomalies. In this small unselected low-risk population, the first-trimester scan detected 83% of aneuploidies and 70% of major structural anomalies. Our results are comparable to previously published studies from other centers and further exemplify the invaluable role of the first-trimester scan in the early detection of aneuploidy and structural anomalies in an unselected low-risk population.

Reliability of the first-trimester cardiac scan by ultrasound-trained obstetricians with high-frequency transabdominal probes in fetuses with increased nuchal translucency

OBJECTIVE

To examine prospectively the reliability of ultrasound-trained obstetricians performing a first-trimester fetal cardiac scan with high-frequency transabdominal probes, by confirming normal or abnormal heart anatomy, in pregnancies referred for increased nuchal translucency thickness (NT).

METHODS

Trained obstetric operators assessed the fetal heart in 133 fetuses with increased NT (> 95th centile) at 11-14 weeks of gestation. A high-frequency transabdominal probe was used to confirm or refute normal cardiac anatomy rather than to establish a specific diagnosis. Following this preliminary screening by the ultrasound-trained obstetrician, specialized fetal echocardiographers rescanned the fetal heart in order to confirm the accuracy of the obstetric operators' findings and to establish a diagnosis in abnormal cases. Fetal cardiologists repeated the examinations at 20 and 32 weeks of pregnancy. Postnatal follow-up lasted 2 years. Twelve fetuses with normal karyotype and normal anatomy were lost to follow-up.

RESULTS

A total of 121 fetuses with increased NT between 11 and 14 weeks' gestation were studied. Congenital heart disease (CHD) was detected in 20/121 (16.5%) fetuses. In addition, there were three with mild ventricular disproportion, the right ventricle being larger than the left, considered as a minor non-specific cardiac abnormality. CHD was associated with chromosomal anomalies in 12/20 (60%) cases. Among the 121 fetuses, there was agreement between ultrasound-trained obstetricians and fetal cardiologists in 116 (95.9%) of the cases, and the ultrasound-trained obstetricians correctly identified 18 cases with major cardiac defects. However, there was disagreement in five cases: two with small ventricular septal defects and three with ventricular disproportion.

CONCLUSIONS

Our results provide evidence that obstetricians, trained to study the heart in the second trimester, can also differentiate reliably between normal and abnormal heart findings in the first trimester, when using a high-frequency transabdominal ultrasound probe.

Role of ultrasonography in early gestation in the diagnosis of congenital heart defects

OBJECTIVE

The purpose of this series was to determine the sensitivity of ultrasonography in early gestation (UEG) using nuchal translucency (NT) and the 4-chamber view (4CV) in the early diagnosis of congenital heart defects (CHDs).

METHODS

This was a retrospective chart review of all patients presenting for UEG between 2002 and 2009. At our center, a survey of fetal anatomy is performed at the time of the NT assessment at 11 weeks to 13 weeks 6 days. A second-trimester scan (STS) is done at 20 to 23 weeks and a third-trimester scan at 32 to 35 weeks. Suspected cases of CHDs were evaluated by a pediatric cardiologist. All neonates were examined at birth by a pediatrician, and when clinically indicated, fetal echocardiography was performed.

RESULTS

A total of 1370 fetuses were scanned. Congenital heart defects were identified in 8 (0.6%). Nuchal translucency was above the 95th percentile for gestational age (GA) in 6 of 8, and the 4CV was abnormal in 6 of 8. Ultrasonography in early gestation detected 75% fetuses with CHDs, and 25% were detected by an STS.

CONCLUSIONS

Our study emphasizes the importance of UEG in the detection of CHDs. In this small unselected low-risk population, UEG detected 75% of CHDs. Nuchal translucency was above the 95th percentile for GA, the 4CV was abnormal, or both in all 8 cases with CHDs.

Increased nuchal translucency in euploid fetuses--what should we be telling the parents?

Nuchal translucency (NT) measurement between 11 and 14 weeks' gestation is an undisputed marker for aneuploidies. When conventional karyotyping is normal, enlarged NT is a strong marker for adverse pregnancy outcome, associated with miscarriage, intrauterine death, congenital heart defects, and numerous other structural defects and genetic syndromes. The risk of adverse outcome is proportional to the degree of NT enlargement. Although the majority of structural anomalies are amenable to ultrasound detection, unspecified genetic syndromes involving developmental delay may only emerge after birth. Concern over these prenatally undetectable conditions is a heavy burden for parents. However, following detection of enlarged NT the majority of babies with normal detailed ultrasound examination and echocardiography will have an uneventful outcome with no increased risk for developmental delay when compared to the general population. Counseling should emphasize this to help parents restore hope in normal pregnancy outcome and infant development.

[First trimester fetal cardiac scanning for fetuses at higher risk for congenital heart disease]

OBJECTIVE

To describe the preliminary results of fetal cardiac scanning in the first trimester of pregnancy for fetuses at higher risk for congenital heart defect (CHD).

PATIENTS AND METHODS

Echocardiographic examination was performed at 12 to 14+6 in 67 patients at higher risk for fetal CHD. The indications for referral were: increased nuchal translucency more or equal to 99(e) centile (56 cases), risk of recurrence for CHD (eight cases), embryonic toxic exposure (eight cases), maternal disease (four cases).

RESULTS

Complete examination of the fetal heart was possible in 54/55 cases. Fetal cardiac examination was normal in 58 cases (87 %). Six cases of severe CHD were diagnosed: hypoplastic left heart syndrome, pulmonary atresia with intact septum, complex univentricular CHD leading to termination of pregnancy, conotroncal Fallot like abnormality, and transposition of great arteries. Post-mortem examination was performed in three cases and confirmed the cardiac anomalies.

DISCUSSION AND CONCLUSION

Our preliminary results confirmed that fetal heart scanning is feasible at the end of the first trimester of pregnancy. Severe CHD are amenable to prenatal diagnosis in the first trimester in the population at higher risk for CHD.

The nuchal translucency and the fetal heart: a literature review

In this overview the current knowledge of the relationship between an increased nuchal translucency (NT) measurement and fetal heart structure and function in chromosomally normal fetuses is reviewed. Relevant pathophysiological theories behind the increased NT are discussed. Fetuses with an increased NT have an increased risk for congenital heart disease (CHD) with no particular bias for one form of CHD over another. This risk increases with increasing NT measurement. Although the NT measurement is only a modestly effective screening tool for all CHD when used alone, it may indeed be effective in identifying specific CHD "likely to benefit" from prenatal diagnosis. The combination of an increased NT, tricuspid regurgitation and an abnormal ductus venosus (DV) Doppler flow profile, is a strong marker for CHD. A fetal echocardiogram should be performed at 20 weeks' gestation in fetuses with an NT > or = 95th percentile but < 99th percentile. When the NT measurement is > or = 99th percentile, or when tricuspid regurgitation and/or an abnormal DV flow pattern is found along with the increased NT, an earlier echocardiogram is indicated, followed by a repeat scan at around 20 weeks' gestation. The resultant increased demand for early fetal echocardiography and sonographers with this special expertise needs to be planned and provided for.

Screening for fetal abnormalities with ultrasound

PURPOSE OF REVIEW

This review serves to explore literature published during the past year that has focussed on sonographic screening for fetal abnormalities.

RECENT FINDINGS

The evolving nature of screening for fetal aneuploidy has continued to feature strongly in recent literature. There is growing interest in early detailed ultrasound of fetal anatomy at the time of nuchal translucency thickness assessment. Demonstration of tricuspid regurgitation and ductus venosus assessment have been shown to be beneficial additional second-line tests for aneuploidy screening in high-risk patients. Frontomaxillary facial angle assessment has been explored as a new marker for aneuploidy. The limitations of first-trimester nasal bone measurement were reiterated while its measurement has been shown to be beneficial in the second trimester, especially when calculated with multiples of the median. As regards second-trimester screening, studies have explored the effectiveness of congenital heart-defect screening and the efficiency of the genetic sonogram for trisomy 21. The role of nuchal translucency discordance in monochorionic twins has also been readdressed.

SUMMARY

Screening for fetal abnormalities continues to evolve with the introduction of novel techniques and the further refinement of previously proposed screening tools. How these modalities are implemented into routine clinical practice remains to be seen.

Fetal echocardiography at 11 + 0 to 13 + 6 weeks using four-dimensional spatiotemporal image correlation telemedicine via an Internet link: a pilot study

OBJECTIVES

To assess whether spatiotemporal image correlation (STIC) volumes from fetuses at 11 + 0 to 13 + 6 weeks' gestation can be obtained by a non-expert and whether fetal echocardiography can be performed via a telemedicine link, providing a remote and reproducible diagnosis of the fetal heart condition.

METHODS

STIC volume datasets from 35 fetuses at 11 + 0 to 13 + 6 weeks were obtained prospectively by a general obstetrician, transmitted via the Internet and subsequently analyzed systematically by two different reviewers. Forty-nine pregnancies were initially enrolled into the study, but adequate volumes were not obtained for 14. Thirty-four datasets were obtained on transabdominal and one on transvaginal ultrasound examination. A checklist was used that included 18 structures and views relating to the fetal heart evaluation, and each reviewer assigned the variables as normal, abnormal or unsure. Cohen's kappa analysis was used to evaluate the agreement between reviewers and the reported findings were compared with the outcome where available.

RESULTS

The mean gestational age was 12 + 3 weeks and the mean (range) crown-rump length was 68 (47-84) mm. The mean maternal age was 33 (range, 26-41) years; 12/35 (34%) were older than 35 years. The four-chamber view obtained was apical in 22/35 (63%) cases and lateral in 13 (37%). Volume datasets were obtained after 12 weeks' gestation in 30/35 fetuses. Three cases had nuchal translucency thickness above the 99(th) percentile, and two of these had an abnormal heart. Five cases had abnormal outcomes. A mean of 3 (range, 1-6) STIC datasets per patient were acquired. The kappa index obtained confirmed interobserver reliability, with good or very good concordance (kappa > 0.6) in 14/18 structures and views related to the heart.

CONCLUSIONS

STIC volumes acquired between 11 + 0 and 13 + 6 weeks' gestation could be sent over the Internet and their analysis enabled recognition of most of the structures and views necessary to assess the small fetal cardiac anatomy, with a high degree of interobserver concordance.

First-trimester ultrasound: current uses and applications

This article is aimed to aid the sonographer and medical care provider in better interpretation and clinical application of first-trimester ultrasound findings in early pregnancy. We review current uses, applications, and interpretations of first-trimester ultrasound. A discussion of basic embryology and normal as well as abnormal first-trimester sonographic findings are discussed. We also cover the utility of the first-trimester ultrasound in screening for fetal aneuploidy. Attention is also given to the role of the first-trimester ultrasound in the prediction of adverse perinatal and maternal outcomes.