Fetal heart volume assessment by three‐dimensional ultrasound

Abstract

Heart volume may provide important information on the status of fetal hemodynamics. However, traditionally fetal heart volume has been assessed with the erroneous assumption that the fetal heart is spherical or elliptical. With the advent of three-dimensional ultrasound, accurate assessment of organ volume has become feasible. The objectives of this study were to compare the reproducibility of two-dimensional ultrasound and three-dimensional ultrasound in the assessment of heart volume, and to test whether heart volume assessed by the traditional method of two-dimensional ultrasound equates to that assessed by three-dimensional ultrasound. If it proved to be significantly different, we aimed to find a new constant which, if incorporated into the traditional formula used to determine heart volume, would enable us to achieve more accurate volumes with two-dimensional ultrasound. In total, 50 normal singleton fetuses ranging from 20 to 30 weeks' gestation were included in the study. Both the traditional two-dimensional and the new three-dimensional volume measurements were compared. The results showed that three-dimensional ultrasound has a better reproducibility than two-dimensional ultrasound in heart volume assessment and that heart volume assessed by the traditional formula of two-dimensional ultrasound is significantly larger than that measured by three-dimensional ultrasound (p < 0.001). We therefore propose that, if the traditional two-dimensional equation is to be used, the constant for heart volume could be modified to 0.4563 (SE = 0.0153, n = 50) to achieve more accurate results. With this new constant, the heart volume derived by two-dimensional ultrasound was not found to differ from that measured by three-dimensional ultrasound. From our series, we conclude that three-dimensional ultrasound is theoretically the best method for the assessment of heart volume. However, because of the limitations of three-dimensional ultrasound (i.e. it is not routinely available, it is more expensive and more time-consuming) two-dimensional ultrasound in practical terms should be the method of choice. Although we were able to improve the accuracy of the heart volume measurements using a new constant in the traditional two-dimensional formula, the new constant will not improve variability, which can only be reduced by three-dimensional ultrasound.

Four-dimensional fetal echocardiography with spatiotemporal image correlation (STIC): A systematic study of standard cardiac views assessed by different observers

“…Three-dimensional [45][46][47][48][49][50][51] and, more recently, four-dimensional ultrasonography of the fetal heart [52][53][54][55][56][57][58] have the potential for making the examination less operator-dependent. Once a volume dataset is acquired, the heart can be examined using multiple planes of section, some of which are unobtainable with two-dimensional ultrasound.…”

Real-time three-dimensional fetal echocardiography: initial feasibility study.

“…As a result some investigators have used nongated fetal threedimensional echocardiography, in which planes from throughout the cardiac cycle are combined offline to generate a single, static volume. 3,5,6,14,15 Clinical results have been mixed, with most groups finding the clarity of nongated fetal cardiac data to be unacceptable for broad clinical use. 3,14,15 A few investigators have developed methods of gating the fetal heart, either by use of M-mode frames to identify the timing of each image 4 or by Fourier transform analysis of fetal cardiac motion.…”

Real-time 3-Dimensional Fetal Echocardiography With an Instantaneous Volume-Rendered Display

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Rapid and facile, 3D imaging allows the acquisition of a volume data set in a matter of seconds, in comparison with the more prolonged interval typically required for conventional fetal cardiac imaging. Thus, whereas conventional fetal cardiac imaging requires a great deal of expertise, acquisition of volume data sets appears far less dependent on operator expertise.…”

“…Although the majority of work in fetal 3D sonographic cardiac imaging has focused on reconstructive techniques, [1][2][3][4][5][6][7][8][9][10][11]14 real-time 3D technology has recently emerged as a potentially superior approach to fetal car-diac imaging. 12,13,15 Although reconstructive techniques acquire a series of planar images over several seconds, real-time approaches acquire entire volumes (rather than single planes) instantaneously, using specialized 2D matrix, phased array transducers.…”