Echogenic intracardiac focus in 2nd-trimester fetuses with trisomy 21: usefulness as a US marker.
OBJECTIVE
To determine whether there is a relationship between the presence of an echogenic intracardiac focus in 2nd-trimester fetuses and trisomy 21 (Down syndrome).


METHODS
A complete genetic ultrasonographic (US) scan was obtained in 3,303 consecutive fetuses with an estimated gestational age of 14.0-24.0 weeks (mean +/- SD, 17.1 weeks +/- 1.75). US was performed in a prospective fashion without any knowledge of karyotype and included assessment of any potential echogenic intracardiac focus (ie, calcified papillary muscle). Karyotypes were obtained in all fetuses. Maternal ages ranged from 13.0 to 47.4 years (mean, 35.1 years +/- 5.1). The prevalence of Down syndrome in this population was 1.6% (53 of 3,303 fetuses).


RESULTS
An echogenic intracardiac focus was seen in 147 of the 3,192 karyotypically normal fetuses (4.6%) and 16 of the 53 fetuses with trisomy 21 (30%). The positive predictive value (PPV) of an echogenic intracardiac focus in this high-risk population was 9.8%; sensitivity, 30%; specificity, 95%; likelihood ratio, 6.6; and relative risk (RR), 8.2 (P <.001). For a sonographically isolated echogenic intracardiac focus, the PPV was 3.7%; sensitivity, 19%; specificity, 95%; likelihood ratio, 4.2; and RR, 4.8 (P =.002).


CONCLUSIONS
A sonographically isolated echogenic intracardiac focus (no other anomalies or markers noted on a complete genetic sonogram) was associated in our high-risk population with a 4.8-fold (95% CI: 1.8, 12.5) increase in RR for trisomy 21 (P =.002).
Department of Radiology, Division of Ultrasound, University of Washington Medical Center, Seattle, WA, USA.
T C
TC
Winter
A M
AM
Anderson
E Y
EY
Cheng
C A
CA
Komarniski
V L
VL
Souter
S B
SB
Uhrich
D A
DA
Nyberg
D000293:Adolescent; D000328:Adult; D002114:Calcinosis / Q000000981:diagnostic imaging; D009202:Cardiomyopathies / Q000000981:diagnostic imaging; D004314:Down Syndrome / Q000000981:diagnostic imaging* / Q000235:genetics; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging* / Q000235:genetics; D005318:Fetal Heart / Q000000981:diagnostic imaging*; D005865:Gestational Age; D006801:Humans; D007621:Karyotyping; D016013:Likelihood Functions; D008297:Male; D008423:Maternal Age; D008875:Middle Aged; D010210:Papillary Muscles / Q000000981:diagnostic imaging / Q000196:embryology; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal