Right Ventricular Flow Vorticity Relationships With Biventricular Shape in Adult Tetralogy of Fallot

Figures

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  Figure 1. Diagrammatic representation of the methodology. 4D flow (A) was used for volumetric quantification of flow in the pulmonary and across the tricuspid valve (B) and velocity data was processed with the 4D flow neural network (C). Vorticity (D) was quantified and visualized with the vortex core and streamlines that demonstrate velocity within the spherical ROI was shown, and the dotted line represents the opening of the tricuspid valve. Cines (E) were used to extract EDV, ESV and SV (F). Cines were also used to build the models for the current population that were projected onto the atlas (G). Regression models (H) were used to compute shape variations associated with vorticity. The figure shows an overlapping of the diagrams of a normal biventricular model and the model generated to show the effect of vorticity.

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  Figure 2. Qualitative (left) and quantitative (right) evaluation of velocity and vorticity with and without the 4DFlownet. The panels show the 3 regions of interest where vorticity was captured (left: whole RV; middle: RVOT; right: tricuspid inflow in diastole. The network reduced noise making the vorticity structure more readily visualized. Right plots show mean vorticity calculated in the region of interest and mean velocity calculated at planes positioned in the RVOT, showing high correlation before and after 4DFlowNet.

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  Figure 3. Correlations of cardiac indices and vorticity with principal component analysis modes. PRVi, indexed pulmonary regurgitant volume; LVM, left ventricular mass; LVEDVi, indexed left ventricular end diastolic volume; LVSVi, indexed left ventricular stroke volume; LVESVi, indexed left ventricular end systolic volume; MVR, mass to volume ratio. Modes 9 and 6 Are the most correlated modes with aspects of cardiac metrics and vorticity. Bonferroni correction was done with all correlations.

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  Figure 4. Principal component shape variations associated with pulmonary regurgitant volume (top) and vorticity (bottom). The RV is shown in purple, left ventricle: green, the tricuspid valve: pink, the pulmonary valve: neon green, the aortic valve: yellow and mitral valve: blue. Each mode is shown in an anterior and posterior view with description below.

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  Figure 5. The effect of vorticity on the shape of the RV by a regression model. The spectrum of shapes is demonstrated in the line of shapes above to show the difference between a normal biventricular model (far right) and a model affected by high vorticity (far left). The larger overlapping shapes emphasize the differences. The RV enlargement affects the orientation of both the pulmonary and tricuspid valves. There is an architectural shift from the normal configuration to an enlarged bulging base. There is an evident effect on the LV as well showing the change in wall shape and position of the aortic and mitral valves due to the shift in the RV outflow tract configuration.