The Principles of Clinical Cytogenetics - Extra Materials - Springer

294 Linda Marie Randolph
Fig. 5. Ultrasound image of intracardiac echogenic foci (indicated by +’s, ×’s, and circles of dots) in a 16-wkgestation
fetus with trisomy 13. No other abnormalities are detected. RV = right ventricle; LV = left ventricle;
RA = right atrium; LA = left atrium. (Courtesy of Greggory DeVore, M.D.)
INTRACARDIAC ECHOGENIC FOCI
Echogenic lesions within the fetal cardiac ventricles have been recognized since 1987, when they
were described in the left ventricles of 3.5% of fetuses examined by ultrasound (158) (see Fig. 5).
The foci were attributed to thickening of the chordae tendinae. Others have reported a 20% incidence
of left-ventricular echogenic foci and right-ventricular foci in 1.7% (159).
The association between left-ventricular echogenic foci and chromosome abnormalities was noted
in a study of 2080 fetuses at 18–20 weeks’ gestation; 33, or 1.6%, had an echogenic focus. Four of
these had chromosome abnormalities (two trisomy 18, one 45,X, and one trisomy 13). All had other
abnormalities, including heart defects (160).
The natural history of intracardiac echogenic foci was studied in a cohort of 1139 patients (161).
Echogenic foci were seen in 41 of 1139 fetuses, or 3.6%. In 38, the foci were in the left ventricle;
in 2, they were in the right ventricle; and in 1, they were in both. None of these fetuses had other
abnormalities. The echogenic foci were again seen in the 27 newborns having echocardiograms up to
3 months of age. The authors pointed out the key clinical significance of echogenic lesions is that
they should be differentiated from intracardiac tumors and ventricular thrombi.
The outcomes of 25,725 ultrasound examinations were reported in a retrospective study from 12
to 24 weeks’ gestation (162). Echogenic intracardiac foci were seen in 44 cases (0.17%). Of the 35
fetuses with left-sided isolated foci, all had uneventful neonatal courses. In nine others, multiple foci
were seen, involving the right ventricle in five cases. Of these, two had uneventful courses, but the
other seven had additional findings, including five with structural or functional cardiac disease
(including one with trisomy 13), one with GM 1 gangliosidosis, and one with echogenic bowel and
missed abortion. The paper includes a useful discussion of the various possible causes of the
echogenic foci, and the authors conclude by agreeing with the consensus that isolated left-ventricular
echogenic foci are a benign finding, but other intracardiac echogenic findings might not be.
Two subsequent publications, in contrast, found a significantly increased risk of trisomy 21 in
fetuses with an intracardiac echogenic focus. In a study by Bromley et al. (163) of 1334 high-risk
second-trimester patients, 66 (4.9%) had an echogenic intracardiac focus. Four of 22 (18%) trisomy