Figure 3
Image analysis for calculation of the systolic flow jet angle: (A) 3-D view showing systolic flow velocity vectors in all slices. (B) Systolic flow jet velocities in the central-most slice in the SOV, which are averaged to determine the flow jet direction (orange in E); (C,D) show the aortic channel direction definitions in the LVOT views. Line segments 1-2 and 3-4 in the LVOT1 view (A) and a-b and c-d in the LVOT2 view (B) are manually drawn to connect the proximal and distal boundaries on both sides of the SOV, which are easily detected landmarks. The vector average of each segment pair defines the projection of the outflow channel direction onto each image plane. These two projections are then used to calculate the channel axis (light blue in E) for calculation of the angle between the flow jet direction vector and channel axis, which quantifies the mis-direction of systolic flow.