Fig. 2.
Real-time reconstructions of the fetal heart for three representative volunteers with increasing levels of motion. Cine movies corresponding to these reconstructions are available as supporting video S1. Time-averaged images of the heart and surrounding anatomy (a, d, g), M-mode displays of signal along the white dashed lines (b, e, h), and plots of displacement (D) versus time (c, f, i), calculated from the real-time reconstructions over a region of interest containing the heart. DX and DY represent the horizontal and vertical components of displacement, respectively. For volunteers two and three, the M-mode displays show fetal cardiac motion (straight arrow) and maternal respiratory motion (curved arrow). For volunteer four, the M-mode display shows the fetal stomach (straight arrow), which is used to identify through-plane motion