[Three-dimensional fetal echocardiography--current status and future prospects]

The purpose of echocardiographic imaging in the fetus is to provide clear representations of the underlying cardiac anatomy. Studies on pre- and postnatal 3D echocardiography have shown this technique can provide an alternative form of image display for comprehensive assessment of congenital heart disease. To date, several different methods are used for 3D echocardiography in the fetus. The technique used at our institution is analogous to the 3D technology employed in studies on neonates and children and uses an electromagnetic location device to register transducer position during data acquisition. As it derives from a complex assembly of sequentially acquired two-dimensional images this technique has important limitations due to fetal movement artifacts and difficulties in cardiac gating. Despite good three-dimensional appreciation of some anatomical detail, this often results in inadequate image quality when compared with 2D echocardiography. Potential advantages of 3D fetal echocardiography include the following: the ability to slice the acquired 3D volume data into an infinite number of two-dimensional cross-sections, and the ability to reconstruct unique three-dimensional views not seen with two-dimensional imaging. However, considering the limitations and the time needed for 3D image processing its practical clinical relevance in the antenatal situation is still not clear. Ongoing research should be aimed toward improved image resolution and applying this new technique to more immediate "on-line" analysis of 3D reconstructions.