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

Objectives To prospectively and quantitatively grade intracardiac echogenic focus/foci (ICEF) using sonographic gain reduction and to determine the as sociation of ICEF by grade with fetal aneuploidy. Methods Women referred for raised maternal age (greater than or equal to 35 years), or > 28 years of age and with a Down syndrome risk greater than or equal to1/270, increased trisomy 18 risk by second trimester serum screen or a prior aneuploid offspring were included in this institutionally approv ed protocol. Only pregnancies of gestational age between 24 and 24 weeks we re included. All women had a targeted ultrasound and were offered fetal chr omosome analysis. The classification of ICEF was made from a four-chamber v iew of the fetal heart. The echo amplitude of the ICEF was compared to that of the thoracic spine and categorized according to the comparative gain se tting at which the image of the relevant structure disappeared: Grade 0 = n o ICEF present, Grade 1 = ICEF image lost before thoracic spine when gain w as reduced Grade 2 = ICEF image lost at same gain setting as thoracic spine , Grade 3 = thoracic spine image lost before ICEF The primary outcome was a prenatally or post-natally detected chromosomal abnormality. Results A total of 885 eligible women were examined during the 21-month stu dy period. ICEF were seen in 29 (3.3%) fetuses: 24(83%) in the left ventric le and five (17%) in the right ventricle. A chromosome abnormality was iden tified in 13/671 (1.9%) fetuses without ICEF (Grade 0) and 0/21 (0%) fetuse s with Grade 1 ICEF. In contrast, two of five (40%) fetuses with Grade 2 IC EF were aneuploid (P =0.005). No Grade 3 ICEF were observed. Additional son ographic abnormalities were seen in both aneuploid fetuses with Grade 2 ICE F. Interobserver agreement on ICEF grading was noted in 50/50 (100%) examin ations (kappa = 1.0). Conclusions Sonographic grading of ICEF is feasible and highly reliable. Gr ade 2 ICEF, especially when accompa nied by additional sonographic markers of a chromosomal abnormality, are associated with aneuploidy significantly more frequently than Grade 2 ICEF.