[Two- and three-dimensional echocardiographic analysis of congenital heart disease in the fetus]

Abstract

Introduction: With increasing experience of obstetric sonographers, a higher proportion of cardiac malformations is found antenatally. However, undiagnosed fetal cardiac defects still result in a significant pre- and postnatal morbidity and mortality. The purpose of two- and three-dimensional echocardiographic imaging in the fetus is to provide clear representations of the underlying cardiac and vascular anatomy. Studies on pre- and postnatal echocardiography have shown these techniques to provide an adequate form of image display for comprehensive assessment of most cases with congenital heart disease.

Methods: To date, two different methods are used for three-dimensional echocardiography in the fetus. The technique currently employed at numerous institutions derives from a complex assembly of sequentially acquired and reconstructed two-dimensional images and is analogous to the 3-D technology assessed in studies on neonates, children, and adults. Although an electromagnetic location device is used to register transducer position during data acquisition, this technique has important limitations due to fetal movement artifacts and difficulties in cardiac gating. This often results in inadequate image quality when compared with 2-D echocardiography. Recent progress in the design and fabrication of higher-frequency real-time volumetric transducers has greatly improved 3-D echocardiographic imaging resolution and allows more immediate three-dimensional "on-line" analysis of cardiac anatomy.

Conclusions: Advantages of 3-D fetal echocardiography include the ability to slice the acquired 3-D 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 current limitations and the time needed for 3-D image processing, its practical clinical relevance in the antenatal situation is not yet clear.