A novel algorithm for comprehensive fetal echocardiography using 4-dimensional ultrasonography and tomographic imaging

Abstract

Objective: Tomographic ultrasound imaging (TUI) is a new display modality that allows simultaneous visualization of up to 8 parallel anatomic planes. This study was designed to determine the role of a novel algorithm combining spatiotemporal image correlation and TUI to visualize standard fetal echocardiographic planes.

Methods: Volume data sets from fetuses with and without congenital heart defects (CHDs) were examined with a novel algorithm that allows simultaneous visualization of the 3-vessel and trachea view, the 4-chamber view, and outflow tracts. Visualization rates for these planes as well as the ductal arch and 5-chamber view were calculated.

Results: (1) Two hundred twenty-seven volume data sets from fetuses without (n = 138) and with (n = 14) CHDs were reviewed; (2) among fetuses without CHDs, the 4-chamber view, 5-chamber view, ductal arch, 3-vessel and trachea view, left outflow tract, and short axis of the aorta were visualized in 99% (193/195), 96.9% (189/195), 98.5% (192/195), 88.2% (172/195), 93.3% (182/195), and 87.2% (170/195) of the volume data sets, respectively; (3) these views were visualized in 85% (17/20), 80% (16/20), 65% (13/20), 55% (11/20), 55% (11/20), and 70% (14/20) of the volume data sets, respectively, from fetuses with CHDs; and (4) simultaneous visualization of the short axis of the aorta, 3-vessel and trachea view, left outflow tract, and 4-chamber view was obtained in 78% (152/195) of the volume data sets from fetuses without CHDs and in 40% (8/20) of those with CHDs.

Conclusions: The 3-vessel and trachea view, the 4-chamber view, and both outflow tracts can be simultaneously visualized using a novel algorithm combining spatiotemporal image correlation and TUI.

Figure 1

An “overview image” is shown on the upper left corner. The parallel lines determine the position of the eight orthogonal planes to the plane containing the “overview image”.

Figure 2

Volume datasets were adjusted to display the four chamber view in panel A, where the fetal aorta was aligned with the crux of the heart in the vertical plane. The reference dot was positioned in the aorta allowing the visualization of the coronal view of the descending aorta in panel C.

Figure 3

In panel C the image was rotated to display the aorta in a vertical position, when necessary. This allowed for the visualization of the longitudinal view of the ductal arch in panel B.

Figure 4

Only three planes were selected, using the “Slices” option, including the plane that crosses the reference dot (which is labeled with an asterisk in the software), one plane to the left (“−1”) and one to the right (“+1”) to the plane crossing the reference dot. These images were magnified using the four panel “Display format”.

Figure 5

In panel A, the image was moved until the reference dot was positioned in the center of the aorta. The “Adjust” option was selected to align the “−1” plane with the ductal arch and the “+1” plane with the external edge of the aorta. This allowed for the simultaneous visualization of the ductal arch in panel A, the three-vessel and trachea view in panel B, the five chamber view in panel C and the four chamber view in panel D.

Figure 6

The “Rotation Y” was selected by clicking on the bar, and the five chamber view was rotated by scrolling on the Y axis until the left outflow tract was visualized in panel B. This allowed for the simultaneous visualization of the short axis of the aorta in panel A, the three vessel and trachea view in panel B, the long axis of the left outflow tract on panel C and the four chamber view on panel D