Thesis: Identification and characterization of boundary conditions for patient-specific biomechanical simulation

PhD defense: Sergei NIKOLAEV

Title: Identification and characterization of boundary conditions for patient-specific biomechanical simulation

Team: MLMS

Abstract: The main purpose of the work is to find a way to estimate the boundary conditions of the liver tissue. Boundary conditions play an essential role in forming the predictive capacity of the biomechanical model, but they are presented mainly by ligaments, blood vessels, and surrounding organs, the properties of which have a "patient-specific" description and can’t be measured reliably. We propose to present the boundary conditions as a nonlinear mass-spring system and estimate its parameters. Firstly, we create a generalized initial approximation of the boundary conditions using the constitutive law available in the literature and a statistical atlas, obtained from a set of models with segmented ligaments. Then, we correct the approximation based on the nonlinear Kalman filtering approach, which assimilates data obtained from a modality during surgical intervention. To assess the proposed approach, we performed experiments for both synthetic and real-data scenarios. The results show a certain improvement in simulation accuracy for the simulations with estimated boundary conditions.

This defense will be held in English and will take place  on the 15th of September at 16.00 CET (UTC + 1) at Salle de conférence Hygie (IHU Strasbourg). This defense will take place in the presence of the jury members listed below:

• Dr. Mathias Brieu, Reviewer - Professor at California State University, USA
• Dr. Grégory Chagnon, Reviewer -Professor at University Grenoble Alpes, France
• Dr. Nadia Bahlouli, Examiner - Professor at University of Strasbourg, France
• Dr. Ole Jacob Elle, Examiner - Research director at Oslo University Hospital, Norway
• Dr. Stéphane Cotin, Advisor - Research director at University of Strasbourg, France

Keywords: Patient-specific modeling, Numerical simulation, Data assimilation, Augmented reality, Biomechanics, Computer-aided surgery, Statistical atlas