SMFM Consult: Isolated echogenic intracardiac focus

August 1, 2013

Guidance on how to proceed when an isolated echogenic intracardiac focus (EIF) is identified on an ultrasound.

 

A 31-year-old G2P1 Caucasian patient presents for a routine fetal anatomic survey at 19 weeks’ gestation. Her current pregnancy has been uncomplicated. An isolated echogenic intracardiac focus (EIF) is identified during her ultrasound. No other anomalies are detected.  

What is an EIF and how commonly do they occur?

An EIF is a small echogenic area appearing within the fetal cardiac ventricle that has a sonographic brightness equivalent to that of bone (Figure). It was first described in 1987 and is most commonly left-sided, although it may be present in either or both ventricles.1 EIF is believed to represent a microcalcification of the papillary muscle. Other specular reflections in the heart may mimic an EIF.2 To avoid this, it is important to image the suspected EIF in multiple planes. 

An EIF is a common finding during a routine second-trimester fetal anatomic survey and is identified in 3% to 5% of normal fetuses. The prevalence of EIF may vary according to maternal ethnicity.3-5 Specifically, one study found that the frequency of EIF was as high as 30% in fetuses of Asian mothers.6 Other studies have supported an increased prevalence of EIF in individuals of Asian, African-American, and Middle-Eastern descent.7

Four-chamber view of the fetal heart with an echogenic focus in the left ventricle

What are the clinical implications of an isolated EIF?

An EIF is not considered a structural or functional cardiac abnormality. It has not been associated with cardiac malformations in the fetus or newborn.8,9 The only reported clinical implication is an increased risk of trisomy 21.3

When an EIF is identified, an experienced provider should perform a detailed fetal anatomic survey to assess for the presence of structural malformations and other sonographic markers of aneuploidy. In addition, the physician should perform an assessment of other risk factors, including maternal age, results of other screening or diagnostic tests, and family history. Most EIFs are isolated and occur in otherwise low-risk pregnancies.

When an isolated EIF is detected, how does counseling differ for women at increased risk for fetal aneuploidy and for women with normal aneuploidy screening results?

All patients, regardless of ultrasound findings, should be offered prenatal screening for aneuploidy and should have the option of invasive diagnostic testing.10,11 Counseling for a woman after prenatal identification of EIF should be guided by presence of other sonographic markers or structural abnormalities, maternal serum screening for risk of Down syndrome (if performed), and maternal age. If an isolated EIF is detected in a woman who has already had an invasive diagnostic test-and the fetal karyotype is known-she can be reassured that the finding is considered a normal variant.

            Numerous studies have described the association between EIF and aneuploidy, specifically Down syndrome.12 Meta-analyses of studies conducted primarily in high-risk pregnancies reported that the risk of trisomy 21 was increased 1.8- to 5.4-fold by the finding of an isolated EIF.3,12,13 Recently, another meta-analysis similarly identified a 2.9 likelihood ratio (LR) for isolated EIF, when defined as no major abnormalities and no evidence of ventriculomegaly, increased nuchal skinfold thickness, echogenic bowel, pyelectasis, short humerus, or short femur.14

A suggested method of risk assessment is to multiply the patient’s a priori risk (based on maternal age or screening) by a published likelihood ratio such as 2.9 as indicated above to generate a modified risk. In women with serum screening indicating an increased risk of trisomy 21 following risk modification, genetic counseling may be helpful. Noninvasive prenatal testing (NIPT) may be a reasonable option for women who are concerned about the procedure-related risk of pregnancy loss. 15,16 If the NIPT result is negative, an isolated EIF may be considered a normal variant because of the extremely low residual risk of trisomy 21. These women, however, should still have the option of an invasive diagnostic test.

Despite the many studies performed to date, there is controversy regarding the significance of EIF in pregnancies at low risk of Down syndrome. With the considerable improvements in imaging technology and aneuploidy screening in recent years, the current risk of trisomy 21 in the setting of isolated EIF is considered low.

Therefore in a woman with a negative aneuploidy screen for Down syndrome (either first- or second-trimester screening) and no visualized fetal structural abnormalities or other aneuploidy markers on a detailed ultrasound, the provider has options. One option is to use the approach highlighted previously, using the LR for risk assessment. For these women at low risk of trisomy 21 pregnancies, other practitioners may consider an EIF a normal variant, and as a result of this perspective, provide no additional counseling or testing.17

 

How should a woman with an isolated EIF be followed throughout pregnancy?

Because an isolated EIF does not represent a cardiac abnormality, fetal echocardiography is not needed and no specific follow-up is recommended. Follow-up should be performed based on the presence of other clinical indications or the results of the patient’s prenatal screening and/or diagnostic testing.

 

References

Schechter AGFakhry JShapiro LRGewitz MH. In utero thickening of the chordae tendinae. A cause of intracardiac echogenic foci. J Ultrasound Med. 1987;6:691–695.

Winn VD, Sonson J, Filly RA. Echogenic intracardiac focus: potential for misdiagnosis. J Ultrasound Med. 2003;22:1207–1214.

Sotiriadis A, Makrydimas G, Ioannidis JP. Diagnostic performance of intracardiac echogenic foci for Down syndrome: a meta-analysis. Obstet Gynecol. 2003;101:1009–1016.

Bromley BLieberman ELaboda LBenacerraf BR. Echogenic intracardiac focus: a sonographic sign for fetal Down syndrome. Obstet Gynecol. 1995;86:998–1001.

Borgida AF, Maffeo C, Gianferarri EA, et al. Frequency of echogenic intracardiac focus by race/ethnicity in euploid fetuses. J Matern Fetal Neonatal Med. 2005;18:65–66.

Shipp TD, Bromley B, Lieberman E, Benacerraf BR. The frequency of the detection of fetal echogenic intracardiac foci with respect to maternal race. Ultrasound Obstet Gynecol. 2000;15:460–462.

Tran SH, Caughey AB, Norton ME. Ethnic variation in the prevalence of echogenic intracardiac foci and the association with Down syndrome. Ultrasound Obstet Gynecol. 2005;26:158–161.

Degani SLeibovitz ZShapiro I, et al. Cardiac function in fetuses with intracardiac echogenic foci. Ultrasound Obstet Gynecol. 2001;18:131–134.

Wax JR, Donnelly J, Carpenter M, et al. Childhood cardiac function after prenatal diagnosis of intracardiac echogenic foci. J Ultrasound Med. 2003;22:783–787.

ACOG Committee on Practice Bulletins. ACOG Practice Bulletin No. 77: screening for fetal chromosomal abnormalities. Obstet Gynecol. 2007;109:217–227.

American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 88, December 2007. Invasive prenatal testing for aneuploidy. Obstet Gynecol. 2007;110:1459–1467.

Nyberg DA, Souter VL, El-Bastawissi A, et al. Isolated sonographic markers for detection of fetal Down syndrome in the second trimester of pregnancy. J Ultrasound Med. 2001;20:1053–1063.

Smith-Bindman R, Hosmer W, Feldstein VA, et al. Second-trimester ultrasound to detect fetuses with Down syndrome: a meta-analysis. JAMA. 2001;285:1044–1055.

14.  Agathokleous M, Chaveeva P, Poon LC, et al. Meta-analysis of second-trimester markers for trisomy 21. Ultrasound Obstet Gynecol. 2013;41:247–261.

Bianchi DW, Platt LD, Goldberg JD, et al. Genome-wide fetal aneuploidy detection by maternal plasma DNA sequencing. Obstet Gynecol. 2012;119:890–901.

Palomaki GE, Kloza EM, Lambert-Messerlian GM, et al. DNA sequencing of maternal plasma to detect Down syndrome: an international clinical validation study. Genet Med. 2011;13:913–920.

Filly RA, Benacerraf BR, Nyberg DA, Hobbins JC. Choroid plexus cyst and echogenic intracardiac focus in women at low risk for chromosomal anomalies. J Ultrasound Med. 2004;23:447–449.

 

Ms. Moyer is a Genetic Counselor and Clinical Manager, San Francisco Perinatal Associates, California.

Dr. Goldberg is Director, Prenatal Diagnosis Center, San Francisco Perinatal Associates, California.

 

This opinion was developed by the Publications Committee of the Society for Maternal-Fetal Medicine with the assistance of Krista Moyer, MGC, and James D. Goldberg, MD, and was approved by the Executive Committee of the Society on March 25, 2013. Neither Ms. Moyer, Dr. Goldberg, nor any member of the Publications Committee (see the list of 2013 members at www.smfm.org) has a conflict of interest to disclose with regard to the content of this article.

Disclaimer: The practice of medicine continues to evolve and individual circumstances will vary. Clinical practice also may vary. This opinion reflects information available at the time of acceptance for publication and is not designed nor intended to establish an exclusive standard of perinatal care. This publication is not expected to reflect the opinions of all members of the Society for Maternal-Fetal Medicine.