Three-dimensional multiplanar time-motion ultrasound or anatomical M-mode of the fetal heart: a new technique in fetal echocardiography.

OBJECTIVE

To assess the application of a three-dimensional multiplanar rendering technique for examination of the fetal heart.

MATERIAL AND METHODS

Free-hand acquisition of a three-dimensional volume was performed without moving or tilting the transducer. While the anatomical plane shows the four cardiac chambers, the two other orthogonal planes show vertical and horizontal time-axis planes as M-mode traces. Because off-line plane positioning is possible on three-dimensional multiplanar reconstruction, M-mode traces can be obtained from different stored cardiac structures independently of the fetal position. Fifty-two women with normal singleton pregnancies at 22-40 weeks underwent transabdominal ultrasound examination and five women with singleton fetuses between 13 and 15 weeks were assessed transvaginally. Clinical application of the echocardiographic technique was tested in a further two fetuses with arrhythmia.

RESULTS

Off-line M-mode traces from atrioventricular valve excursions and myocardial contractions were possible in 45/52 (86.5%) cases examined at 22-40 weeks. Among the 32 fetuses in which visualization of the outflow tracts was attempted, M-mode traces of the aortic and pulmonary valves were possible in 22 (68.7%) and 20 (62.5%) cases, respectively. In three of five cases examined transvaginally, M-mode traces could be registered. Both cases with supraventricular extrasystoles (26 and 31 weeks) were easily diagnosed using this technique.

CONCLUSION

The new technique presented here enables the easy acquisition of optimal M-mode traces from different fetal heart structures. Based on our promising findings we would recommend that, in the future, three-dimensional multiplanar imaging should not be limited to automatic volume acquisition but should include the free-hand technique.