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. Copyright 2003 ISUOG. Published by John Wiley & Sons, Ltd.