Interactive editing of virtual chordae tendineae for the simulation of the mitral valve in a decision support system

Figures

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  Fig. 1. a–b Long axis views of the left heart. Some anatomical structures, landmarks, and acquisition artifacts are highlighted. Disadvantages of TEE acquisitions are shadowing and signal dropout artifacts. In addition, the leaflets can be positioned very close to the myocardium in the open state, while in the closed state, the coaptation zone (area where the leaflets meet) can be difficult to assess. a Normally closing valve; b abnormally closing valve showing prolapse

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  Fig. 2. a Overview of the complete simulation setup. BC refers to boundary condition. b Setup for defining the chordae tendineae. The papillary muscle tips \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {V}^{PM}_{i}$$\end{document}ViPM are connected to the leaflet vertices \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {V}_{j}$$\end{document}Vj via edge \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal {E}^{CT}_{ij}$$\end{document}EijCT (gray lines). In this case, light blue and light red colored vertices connect to one PM tip, while the darker blue and darker red colored vertices are connected to the other PM tip. The…

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  Fig. 3. Overview of the interactive editor. The panel marked with 1 shows the image plane that belongs to the current selected cord end point marked as a yellow cross. The same cord end point is shown as a green sphere in panel 4 which depicts the 3D view of the open MV and the model cords. Panel 2 shows, in addition to coordinates and indices, the length of the cords. Panel 3 represents the interaction with the user. Here, the user can choose to scale individual cord lengths, or scale the lengths of one of the four groups of cords, or scale the lengths of all cords at once

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  Fig. 4. Interactive editor showing the closed valve. The selected cord end point is shown in yellow in panel 1 and in green in panel 4 (see Fig. 3 for panel numbering). The prolapsing valve is overlaid on the image data for visual comparison. By using the controls in the top right corner (panel 3), the cord lengths can be manipulated while the simulation is running. This way, changes can be evaluated immediately

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  Fig. 5. a Example of manually drawn tracings (shown in blue) of a closed valve shown in 3D. The tracings were defined in 2D on a limited number of image planes of the entire volume. The annulus contour is shown in dark orange. b Detail view of the cord setup in 3D. The annulus plane (AP) is shown as a blue rectangle, while the annulus center of gravity is depicted as a black sphere in its center. The AP normal is shown as a black line originating from the center. The annulus contour intersects the AP and is shown in dark orange if located above the AP. The orifice contour is shown in light orange. The manually placed leaflet vertices marking the cord end points are shown as red (anterior) and blue (posterior) spheres. The pink sphere marks the center of gravity of the chosen leaflet vertices, the green sphere shows the corresponding heuristically calculated papillary muscle tip. The green line is parallel to the AP normal and points to the AP. It touches the center of gravity of the chosen vertices (see construction in text). The gray lines depict the generated cords in open state and are shown for both PM tips

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  Fig. 6. a Overlay of simulation result (brown), manual tracings (blue) and distance measurements (green, projection of manual tracings onto valve surface). The tracings can be used to assess the pathology as well as the simulation outcome. The case shown is B5 in which the pathology was predicted in a different location on the opposite leaflet using the heuristic parameterization. b By changing individual cords lengths, the result was vastly improved. The prolapse is now in the right location and the geometry shows good approximation