Blood Speckle Imaging: An Emerging Method for Perioperative Evaluation of Subaortic and Aortic Valvar Repair

Figures

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  Figure 1. Blood speckle imaging (BSI) data (a) consisting of tissue (single channel) and velocity (multi-channel). The multichannel data were combined into a velocity field and then mapped onto the 2D grid (b) for visualization and quantification of the flow (c).

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  Figure 2. Pre-operative transesophageal echocardiographic evaluation. (A) Color Doppler comparison in the systole demonstrates flow acceleration starting at the level of the subaortic membrane (the membrane is outlined with red hashed lines in this and the other panels). (B) BSI in the systole demonstrates narrowing of the outflow jet at the level of the subaortic membrane with subsequent turbulence. (C) 3D long-axis imaging in the systole shows the prominent subaortic membrane which has an attachment to the nadir of the right coronary leaflet (black asterisk) with mild thickening of the leaflet extending from the leaflet hinge to the tip. (D) 3D imaging in the systole viewing in the short axis from the apex of the ventricle looking up towards the left ventricular outflow tract demonstrates the circumferential membrane which is most prominent under the coronary leaflets. (E) 3D short axis of the aortic valve in the diastole (F) with a 3D color Doppler demonstrates the trileaflet aortic valve with notable thickening of the right coronary leaflet (RCL) with mild to moderate central regurgitation. LCL, left coronary leaflet; NCL, non-coronary leaflet.

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  Figure 3. Post-operative transesophageal echocardiographic evaluation. (A) Color Doppler comparison in the systole demonstrates no significant residual subaortic membrane with laminar flow across the left ventricular outflow tract and the aortic valve. (B) BSI in the systole confirms laminar flow. (C) 3D long-axis imaging in the systole shows a very trivial residual subaortic membrane near the nadir of the right coronary leaflet (black asterisk) with a noticeably thinner right coronary leaflet. (D) 3D short axis of the aortic valve in the diastole (E) with a 3D color Doppler demonstrates notable thinning of the right coronary leaflet (RCL) tip with improve coaptation and no significant residual regurgitation. LCL, left coronary leaflet; NCL, non-coronary leaflet.

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  Figure 4. Parasternal long-axis view of the left ventricular (LV) outflow tract and the aortic valve (AV) showing the BSI confidence level, with range 0 as low and 1 as high confidence. The TEE probe has the same orientation as in Figure 1 and the confidence level is shown at the beginning of systole t/T=0, peak systole t/T=0.2, towards the end of systole t/T=0.4, and during diastole t/T=0.8. Pre-operative images are displayed across the top panels and post-operative images across the bottom panels.

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  Figure 5. Parasternal long-axis view of the left ventricular (LV) outflow tract and the aortic valve (AV) showing the velocity field at different time instants during the cardiac cycle, where the vector color indicates the velocity magnitude. The TEE probe has the same orientation as in Figure 1. Pre-operative images are displayed across the top panels and post-operative images are displayed across the bottom panels.

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  Figure 6. Continuous-wave Doppler assessment from the pre-operative (left panel) and post-operative (right panel) transesophageal echocardiographic studies.

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  Figure 7. (a) Maximum velocity at peak systole as a function of the cardiac cycle for pre- and post-operative cases, for BSI and continuous-wave (CW) Doppler data, respectively. The maximum velocity is evaluated as the maximum valve on the white dashed lines in Figure 5. (b) Confidence level as a function of the cardiac cycle for the pre- and post-operative cases (evaluated as the mean value on the white dashed lines in Figure 5).

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  Figure 8. The long-axis velocity component (V) is given as a function of the short-axis (Y) for (a) pre-operative and (b) post-operative cases. The long-axis shear stress (μ∂V/∂y) component is given on the bottom row for (c) pre-operative and (d) post-operative cases. Both the velocity and the shear stress are given at different instances of the cardiac cycle (t/T=0,0.2,0.4,0.8). The location of the profiles is along the white dashed line, annotated in Figure 5. The y-direction corresponds with the short axis, where a lower y is towards the anterior wall (higher up in the screen and closer to the probe, c.f. Figure 2 and Figure 3) and a higher y is towards the posterior wall (more distal to the probe).