A preliminary study of sonographic grading of fetal intracardiac echogenic foci: feasibility, reliability and association with aneuploidy

Role of Sonographic Second Trimester Soft Markers in the Era of Cell-Free DNA Screening Options: A Review

Soft markers are sonographic structural, nonspecific signs with little pathological significance, often transient, usually considered as normal variants. However, they may also be associated with chromosomal abnormalities. The most widely examined soft markers include absent or hypoplastic nasal bone (NB), intracardiac echogenic focus (IEF), ventriculomegaly (VM), thickened nuchal fold (NF), choroid plexus cyst (CPC), echogenic bowel, short long bones, and urinary tract dilation (UTD). Although the use of noninvasive prenatal testing (NIPT) has been spreading quickly in maternal–fetal medicine, it is not a diagnostic test and it still remains unavailable or cost-prohibitive for most of the population in many countries. After normal screening test results in the first trimester, there is no uniform consensus regarding the clinical significance of isolated soft markers for aneuploidy. Nowadays, the search for soft markers in an ultrasound is still part of clinical evaluation, and the interpretation of these findings is often a matter of debate. In the present review, we summarize the recent literature about the role of soft markers in the era of NIPT and propose an overview of the different clinical guidelines.

Application of Copy Number Variation Detection to Fetal Diagnosis of Echogenic Intracardiac Focus During Pregnancy

Echogenic intracardiac focus (EIF) is one of the most common ultrasound soft markers (USMs) in prenatal screening. However, the association of EIF with chromosomal abnormalities is still controversial. From January 2018 to April 2020, a total of 571 fetuses with USMs in our center were enrolled, among which 150 (26.27%) presented EIFs. We analyzed the karyotype anomalies and copy number variations (CNVs) in fetuses who presented EIFs by comparing their ultrasound indications, maternal ages and gestational stages. There were no statistically significant differences in the incidence of chromosomal abnormalities between fetuses with EIFs and the fetuses with USMs (4.00 vs. 7.71%, p = 0.112). Additionally, the incidence of chromosomal abnormalities was not related to maternal age (4.10% in maternal age below 35 yeas vs. 3.57% in maternal age above 35, p = 1.000). Interestingly, after 28 weeks of gestation, fetuses with EIFs showed more chromosomal abnormalities (20.00%) than that in the group before 28 weeks of gestation (2.22%, p = 0.014), and this result was attributed to the detection of pathogenic CNVs. After birth, 25 of children conducted cardiac development re-examination. Among them, 9 (36%, 9/25) were diagnosed with congenital heart disease, primarily patent foramen oval and ventricular septal defects (7/9, 77.77%). We concluded that the appearance of EIFs in early or mid-trimester would not indicate an increased risk of fetal chromosomal abnormalities. However, the persistence of EIFs in late trimester was associated with a higher risk of pathology-related CNVs and its persistent appearance may indicate heart development defects after birth. Thus, our results suggest that CNV detection has its advantages in prenatal diagnosis, especially for those with EIFs that persist in the third trimester.

Meta-analysis of validity of echogenic intracardiac foci for calculating the risk of Down syndrome in the second trimester of pregnancy

Echogenic intracardiac foci are a second trimester marker associated with aneuploidy in high-risk populations. The objective of this study is to assess the validity of echogenic intracardiac foci for Down syndrome detection in the second trimester ultrasound scan. A systematic search in major bibliographic databases was carried out (MEDLINE, EMBASE, CINAHL). Twenty-five studies about echogenic intracardiac foci were selected for statistical synthesis in this systematic review. Those 25 considered to be relevant were then subjected to critical reading, following the Critical Appraisal Skills Programme criteria, by at least three independent observers. Then, the published articles were subjected to a meta-analysis. A global sensitivity of 21.8% and a 4.1% false positive rate were obtained. The positive likelihood ratio was 5.08 (95% confidence interval, 4.04-6.41). The subgroups analysis did not reveal statistically significant differences. In conclusion, echogenic intracardiac foci as an isolated marker could be a tool to identify-rather than exclude-the high-risk group of Down syndrome, although it should be noted that it shows low sensitivity.

True Reproducibility of UltraSound Techniques (TRUST): systematic review of reliability studies in obstetrics and gynecology

OBJECTIVES

To examine the quality of methods used and the accuracy of the interpretation of agreement in existing studies that examine the reliability of ultrasound measurements and judgments in obstetrics and gynecology.

METHODS

A systematic search of MEDLINE was performed on 25 March 2014, looking for studies that examined the reliability of ultrasound measurements and judgments in obstetrics and gynecology with evaluation of concordance (CCC) or intraclass (ICC) correlation coefficients or kappa as a main objective.

RESULTS

Seven hundred and thirty-three records were examined on the basis of their title and abstract, of which 141 full-text articles were examined completely for eligibility. We excluded 29 studies because they did not report CCC/ICC/kappa, leaving 112 studies that were included in our analysis. Two studies reported both ICC and kappa and were counted twice, therefore, the number used as the denominator in the analyses was 114. Only 16/114 (14.0%) studies were considered to be well designed (independent acquisition and blinded analysis) and to have interpreted the results properly. Most errors occurring in the studies are likely to overestimate the reliability of the method examined.

CONCLUSIONS

The vast majority of published studies examined had important flaws in design, interpretation and/or reporting. Such limitations are important to identify as they might create false confidence in the existing measurements and judgments, jeopardizing clinical practice and future research. Specific guidelines aimed at improving the quality of reproducibility studies that examine ultrasound methods should be encouraged.

Echocardiography in children with Down syndrome

Congenital heart disease is a common problem in children with Down syndrome (DS). Echocardiography plays an important role in the detection of both structural and functional abnormalities in this group of patients. Fetal echocardiography can help in the early recognition of DS by detecting soft markers of DS, but its main role is to define the exact nature of the suspected cardiac problem in the fetus. Postnatal echocardiography is mandatory in the first month of life for all neonates with DS. It is also indicated before any cardiac surgery and for serial follow-up after cardiac surgery. In this article, we discuss the types and mechanism of cardiac abnormalities in DS children and the role of both fetal and postnatal echocardiography in the detection of these abnormalities.

Echocardiography in children with Down syndrome

Congenital heart disease is a common problem in children with Down syndrome (DS). Echocardiography plays an important role in the detection of both structural and functional abnormalities in this group of patients. Fetal echocardiography can help in the early recognition of DS by detecting soft markers of DS, but its main role is to define the exact nature of the suspected cardiac problem in the fetus. Postnatal echocardiography is mandatory in the first month of life for all neonates with DS. It is also indicated before any cardiac surgery and for serial follow-up after cardiac surgery. In this article, we discuss the types and mechanism of cardiac abnormalities in DS children and the role of both fetal and postnatal echocardiography in the detection of these abnormalities.

Prenatal ultrasonographic measurement of the fetal iliac angle during the first and second trimester of pregnancy

OBJECTIVES

The aim of this study was to present our results of the sonographic measurement of the fetal iliac angle during the first and second trimesters of pregnancy.

METHODS

A total of 2168 fetal iliac angle measurements were performed in a transverse section of the fetal pelvis. The iliac angle measurements were compared in fetuses with trisomy 21 (n = 52) and fetuses with normal karyotype (n = 1980). The sensitivity, specificity, positive predictive value, negative predictive value and false positive rate in trisomy 21 fetuses were compared for multiple cut-off value. Statistical significance for measurements was estimated for trisomy 21.

RESULTS

A total of 2064 fetuses had adequate images for satisfactory measurement of the iliac wing angle and 1831 patients asked for a genetic invasive procedure. Of the fetuses with chromosomal aberrations, only the fetuses with trisomy 21 were included in the investigation. The risk of trisomy 21 in our population was 1 of 39. In the euploid fetuses, the mean iliac wing angle was 63.72°. The mean iliac wing angle in the fetuses with trisomy 21 was 90.32°, significantly higher than those seen in fetuses with normal karyotype.

CONCLUSION

The proven larger iliac wing angle in neonates with Down syndrome can be demonstrated sonographically during the pregnancy, especially in the first and second trimesters. This marker may be useful in prenatal screening or exclusion of trisomy 21.

Intracardiac echogenic focus and fetal outcome

BACKGROUND

To study the outcome of the fetuses with intracardiac echogenic focus (ICEF).

METHODS

All patients who were found to have one or more ICEF on sonographic (US) examination at our center from January 2007 through January 2009 were included in this retrospective study. ICEF was defined as a discrete area of echogenicity noted in the left or right ventricle, which was as bright as bone. Patients were followed up to know pregnancy outcome.

RESULTS

Of 762 fetuses evaluated by US, 48 (6.3%) were found to have an ICEF. Thirty-one of these 48 fetuses had an isolated ICEF; 11 had associated major malformations, and the remaining 6 had no major US abnormalities but were found to have other soft markers. Invasive prenatal testing was done in 21 cases for risk factors other than ICEF and was found to be abnormal in two cases. Seven pregnancies were terminated due to associated major malformations.

CONCLUSION

The prevalence of ICEF was 6.3%. Of 31 fetuses with an isolated ICEF, outcomes of 28 fetuses are known and all neonates were reported to be normal at birth. Thus we infer that the presence of an isolated ICEF has no adverse effect on outcome of the neonate.

Intracardiac echogenic foci have no hemodynamic significance in the fetus

Intracardiac echogenic foci (ECFs), probably representing microcalcifications of the papillary muscles, are a common finding in fetal ultrasonic screening examinations. Their significance is unclear, and their value as markers for chromosomal anomalies is debatable. It also is unknown whether ECFs predict abnormal cardiac performance. This prospective study analyzed and compared the systolic and diastolic properties of the heart in 28 fetuses with ECFs and 70 fetuses without ECFs using both conventional and novel myocardial deformation methods. The findings suggest that left-sided ECFs do not predict depressed left- or right-side systolic or diastolic properties in the fetus. A longitudinal study that would follow ECF fetuses into their childhood is warranted to confirm the findings of this study.

The association of maternal BMI with fetal echogenic intracardiac foci and echogenic bowel

OBJECTIVES

To evaluate the impact of maternal body mass index (BMI) as well as maternal ethnicity on the detection of either echogenic intra-cardiac focus (EIF) or echogenic bowel (EB).

METHODS

This prospective study identified 74 uncomplicated singleton fetuses in which EIF and/or EB were detected between 18 and 21 weeks of gestation (i.e. study group). Seventy four consecutively scanned fetuses without EIF or EB, at the same gestational age, were selected as controls. The differences in maternal BMI and maternal ethnicity were compared between the two groups using the chi(2) test, Fisher's exact test, and the Student t-test. A multivariable logistic regression model was constructed to control for confounders. Odds ratios (OR) and their 95% confidence interval (CI) were computed.

RESULTS

The mean maternal BMI was significantly lower in the study group as compared to controls (22.9 +/- 3.1 vs. 28.0 +/- 7.5 kg/m(2), respectively; p < 0.0001). Patients with fetal EIF and/or EB were significantly more likely to be Asians (20.3% vs. 5.4%, OR = 4.5; 95% CI 1.3-16.9). Using a multivariable analysis, controlling for ethnicity, the association between maternal BMI and fetal EIF or EB remained significant (OR = 0.83; 95% CI 0.76-0.91). However, based on this model Asian ethnicity was not an independent risk factor for the detection of EIF and/or EB (OR = 2.6; 95% CI 0.8-8.9).

CONCLUSIONS

Our data suggests an inverse relationship between the maternal BMI and the detection of fetal EIF and/or EB. Moreover, it appears that low maternal BMI, and not Asian ethnicity, is an independent risk factor for the detection of these echogenic fetal findings.

[Role of "subtle" ultrasonographic signs during antenatal screening for trisomy 21 during the second trimester of pregnancy: meta-analysis and CPDPN protocol of the Grenoble University Hospital]

OBJECTIVE

A meta-analysis about subtle ultrasonographic signs in second trimester of pregnancy.

MATERIALS AND METHODS

196 articles dealing with the subject--from 1985 to July 2002--were studied. Data on the 11 reported signs were collected from 92 theoretically and/or statistically valid studies. Then, the studies were selected according to several criteria: isolated characteristic, defined thresholds, calculable sensitivity and specificity. After checking for homogeneity, a likelihood ratio was calculated for some of the signs.

RESULTS

This meta-analysis of the second trimester ultrasonographic signs of Down's syndrome enabled us to estimate the likelihood ratio (LHR) of six signs. At 22 weeks'gestation (WG) these signs are: pyelectasis equal to or greater than 5 mm; nuchal fold thickness equal to or greater than 6 mm; persistence of choroid plexus cysts; shortness of the femur and humerus below the tenth percentile; hyperechogenic bowe; and nasal bone length less than 2.5 mm.

CONCLUSION

These validated ultrasonographic signs are independent of nuchal translucency thickness at 12 WG and of maternal serum biochemistry. This allows to calculate a combinate risk for nuchal translucency, maternal serum biochemistry and second trimester ultrasonographic signs when they are validated.

Controversial ultrasound findings

This article has reviewed a few of the more controversial findings in the field of obstetric ultrasound. For each one evidence-based strategies for the management of affected pregnancies have been suggested, derived from what the authors believe is the best information available. In some cases, this information is very limited, which can make counseling these patients extremely difficult. Some physicians find using specific likelihood ratios helpful in these complex discussions. An example of the relative likelihood ratios for several markers of trisomy 21 is illustrated in Table 10. Although the management of each of the findings discussed in this article is different, a few generalizations can be made. To begin with, the detection of any abnormal finding on ultrasound should prompt an immediate detailed ultrasound evaluation of the fetus by someone experienced in the diagnosis of fetal anomalies. If there is more than one abnormal finding on ultrasound, if the patient is over the age of 35, or if the multiple marker screen is abnormal, an amniocentesis to rule out aneuploidy should be recommended. Of the six ultrasound findings reviewed here, the authors believe that only echogenic bowel as an isolated finding confers a high enough risk of aneuploidy to recommend an amniocentesis in a low-risk patient. The other findings in isolation in a low-risk patient seem to confer only a modest increased risk of aneuploidy, if any, and this risk is certainly less than the risk of unintended loss from amniocentesis. Wherever possible, modifiers of this risk, such as maternal age, history, and first and second multiple marker screening, should be used to define more clearly the true risk of aneuploidy. As obstetric ultrasound moves forward, particularly into the uncharted waters of clinical use of three- and four-dimensional ultrasound, one can expect a whole new crop of ultrasound findings with uncertain clinical significance. Clinicians are well advised to await well-designed studies to determine the clinical significance of these findings before altering clinical care.

Are intracardiac echogenic foci markers of congenital heart disease in the fetus with chromosomal abnormalities?

OBJECTIVE

To determine whether intracardiac echogenic foci (ICEF) are markers of congenital heart disease (CHD) in fetuses with chromosomal abnormalities.

METHODS

We identified all fetuses with chromosomal abnormalities undergoing targeted sonography at 17 weeks' to 21 weeks 6 days' gestation in a single perinatal center from January 1, 1994, to June 30, 2003. Offspring with and without CHD were compared for the presence or absence of ICEF.

RESULTS

Two (8%) of 25 fetuses with ICEF had CHD versus 38 (33.3%) of 114 fetuses without ICEF (P = .006). Similarly, 1 (5.5%) of 18 fetuses with trisomy 21 and ICEF had CHD compared with 16 (37.2%) of 43 fetuses with trisomy 21 without ICEF (P = .009).

CONCLUSIONS

Intracardiac echogenic foci in fetuses with chromosomal abnormalities, including those with trisomy 21, are not useful markers for CHD.

An isolated echogenic heart focus is not an indication for amniocentesis in 12,672 unselected patients

OBJECTIVE

To evaluate the risk of Down syndrome in fetuses with a heart echogenic focus using the Bayes theorem and likelihood ratios in an unselected population.

METHODS

We prospectively evaluated 12,672 second-trimester sonographic features and extracted and examined a population with an echogenic focus for chromosomal anomalies.

RESULTS

There were 479 cases of echogenic focus; 90.4% were isolated, whereas 9.6% had associated findings. Eleven patients had fetuses with trisomy 21 (9 per 10,000). Eight of those did not have an echogenic focus, whereas 3 had a heart echogenic focus. Only 1 fetus with trisomy 21 had an isolated echogenic focus. The positive likelihood ratio for total cases of a heart echogenic focus and trisomy 21 was 7.25, whereas for an isolated echogenic focus, the positive likelihood ratio was 2.66.

CONCLUSIONS

The results of the statistical analysis showed that the risk of aneuploidy is increased in fetuses with an echogenic intracardiac focus; however, the finding should prompt a detailed structural survey and correlation with a priori risk. Amniocentesis need not be offered to patients who are otherwise at low risk and have an isolated echogenic intracardiac focus.

Childhood cardiac function after prenatal diagnosis of intracardiac echogenic foci

OBJECTIVE

To determine whether prenatally diagnosed intracardiac echogenic foci are associated with childhood cardiac dysfunction and persistence.

METHODS

Children in whom intracardiac echogenic foci were shown on prenatal sonography at 1 perinatal center underwent echocardiography at ages 2 to 7 years. A single pediatric cardiologist, blinded to the prenatal sonographic intracardiac echogenic focus locations, assessed cardiac function by measuring the left ventricular shortening fraction and myocardial performance index. The presence of tricuspid and mitral valve regurgitation was also sought. The secondary outcome was intracardiac echogenic focus persistence.

RESULTS

Twenty-five children, 14 (56%) male and 11 (44%) female, were examined at a mean age +/- SD of 3.0 +/- 1.0 years. Prenatally, 18 children (72%) had left ventricular intracardiac echogenic foci, and 7 (28%) had right ventricular intracardiac echogenic foci. The left ventricular shortening fraction was normal in all children. The overall mean left ventricular myocardial performance index (reference value, 0.36 +/- 0.06), was normal for both children with left ventricular intracardiac echogenic foci (0.36 +/- 0.06) and those with right ventricular intracardiac echogenic foci (0.36 +/- 0.04). Two children with left ventricular intracardiac echogenic foci had an isolated left ventricular myocardial performance index of greater than 2.5 SD above the mean. Trace tricuspid valve regurgitation and mitral valve regurgitation were noted in 13 (52%) and 2 (8%) of the children, respectively, similar to the general population. Left ventricular intracardiac echogenic foci persisted in 16 children (89%), whereas right ventricular intracardiac echogenic foci persisted in 2 (29%) (P = .007).

CONCLUSIONS

Prenatally diagnosed intracardiac echogenic foci are often persistent but not associated with childhood myocardial dysfunction.

Sonographic grading of fetal intracardiac echogenic foci in a population at low risk of aneuploidy

PURPOSE

We screened pregnant women at low risk of a fetal chromosomal abnormality for the presence of fetal intracardiac echogenic foci (ICEF) and graded those foci by using sonographic gain reduction. Our objectives were to determine the interobserver reliability of the technique and the association of ICEF, by grade, with fetal aneuploidy.

METHODS

Pregnant women who were 18-35 years old, at low risk for fetal chromosomal abnormalities, and referred for targeted sonography at 16-24 weeks' menstrual age were eligible to participate. All patients whose fetuses had ICEF were offered fetal chromosomal analysis. The presence of ICEF was ascertained by an apical 4-chamber view of the fetal heart and graded independently by 2 examiners blinded to each other's assessment. Grading was based on the difference in echogenicity of the ICEF and the thoracic spine as the ultrasound gain was reduced; in grade 1, the ICEF image was lost before that of the thoracic spine; in grade 2, the ICEF and thoracic spine images disappeared at the same gain setting; and in grade 3, the thoracic spine image was lost before that of the ICEF.

RESULTS

During the 6-month study period, 383 eligible women were examined, and ICEF were seen in 35 fetuses (9.1%): 25 (71.4%) in the left ventricle, 1 (2.9%) in the right ventricle, and 9 (25.7%) in both ventricles. ICEF grading was successfully performed in all 33 of the women with fetal ICEF who elected to participate. Twenty-one (63.6%) had grade 1, 9 (27.3%) had grade 2, and 3 (9.1%) had grade 3 ICEF. Interobserver agreement was noted in 27 (90.0%) of 30 available paired second-trimester observations (kappa = 0.8), indicating excellent agreement. Two fetuses (6.1%) with grade 1 ICEF but no other risk factors for aneuploidy had chromosomal abnormalities, as compared with 1 fetus (0.3%) in the control group, which had no ICEF (p = 0.02).

CONCLUSIONS

Sonographic grading of ICEF is feasible and reliable. The presence of fetal ICEF in a population otherwise at low risk for aneuploidy seems to warrant the performance of fetal chromosomal analysis.

The value of minor ultrasound markers for fetal aneuploidy

As a result of improvements in ultrasound image quality and scanning technique, an increasing number of subtle morphological changes in fetal anatomy have been identified in the second trimester. Most of these ultrasound features were originally described as normal variants of development with no clinical significance. However, subsequent studies in high-risk populations showed that some of these variants were more prevalent in fetuses with chromosomal defects and therefore proposed as prenatal markers for the detection of aneuploidy. The implications for pregnancy management when one of these so-called minor ultrasound markers is detected have been a matter of continuous controversy in the field of prenatal diagnosis and yet the definitive answer on their clinical significance in the low-risk population is still debated.