Sonographic grading of fetal intracardiac echogenic foci in a population at low risk of aneuploidy.
OBJECTIVE
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.
Wax
Joseph R
JR
Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Maine Medical Center, 887 Congress Street, Suite 200, Portland, Maine 04102, USA.
Cartin
Angelina
A
Pinette
Michael G
MG
Blackstone
Jacquelyn
J
Michaud
Janet
J
Byers
Susan
S
Boutin
Nancy
N
D000293:Adolescent; D000328:Adult; D000782:Aneuploidy; D002869:Chromosome Aberrations; D025063:Chromosome Disorders; D004314:Down Syndrome / Q000000981:diagnostic imaging; D005260:Female; D005318:Fetal Heart / Q000000981:diagnostic imaging*; D006801:Humans; D010210:Papillary Muscles / Q000000981:diagnostic imaging; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D015203:Reproducibility of Results; D012307:Risk Factors; D016216:Ultrasonography, Prenatal