Daryna Panicheva (Magrit) will defend here thesis on Wednesday, March 17th at 9:30.
The defense will be held in English and is entitled “Image-based mitral valve modeling for biomechanical applications“. Her thesis is supervised by Marie-Odile Berger and Pierre-Frédéric Villard (Magrit).
Methods for the valve components segmentation and their integration into the model have been proposed. We focused on automatic chordae extraction as it would improve the simulation reproducibility on various data examples, and thus help to advance towards patient-based clinical applications.
The procedure proposed for the automatic extraction of the chordae consists of three steps. First, the segmentation of the chordae is obtained with the method based on the topological properties of the structures. Then, the representation of the geometry in a form of trees of connected line segments is extracted using the tracking approach combined with the local fitting of a cylindrical model. In order to make the geometry resulting from these methods consistent with the biomechanical model, the final stage of the chordae structure optimization is applied. In particular, the optimization makes it possible to reduce slack in the chordae and to correct false topological configurations by taking into account mechanical and anatomical considerations associated with image data.
We have proposed a validation metric for the segmentation results based on the graph similarity. With this metric correspondences between the chordae obtained with our automatic method and those resulting from the manual segmentation are defined, as well as the quality of the segmentation is assessed.
We then demonstrated the application of the extracted chordae geometry in the biomechanical simulation of the closed valve state. The consistency of the reproduced behavior was verified by comparing the results obtained with the chordae from our automatic procedure and the ground truth chordae. The bulging volume and the mechanical stress distribution have been used as quantitative criteria. The coherence of the simulation was also analyzed on a modeled pathological case with ruptured chordae.
