Master Internship Biomechanics

**Master’s Internship 2025**

**Subject**: Optimization of the reconstruction of viscoelastic parameters obtained by a Non-Linear Inversion method on _in vitro_ Magnetic Resonance Elastography data

**Duration**: 6 months (from February)

**Location**: MAGICS team of CREATIS laboratory. Bâtiment Léonard de Vinci Campus La Doua, 21 avenue Jean Capelle, 69621 Villeurbanne, France

**Description and aim of the internship**:
The proposed research project specifically aims to study the performance of the NLI reconstruction algorithm compared to the algorithm traditionally used. Images will be acquired on a preclinical MRI[5] where various parameters such as field of view, image resolution, and wave frequencies are significantly different from those encountered in clinical settings, where the NLI method has been developed and tested. Multi-frequency MRE data will be acquired using a preclinical MRI on the PILoT imaging platform, using samples created to simulate various _in vivo_ scenarios. This internship will be jointly supervised by E. Van-Houten from the University of Sherbrooke (video conference meetings are planned) and may benefit from the use of the 'Calcul Canada' infrastructure for performing numerical computations.

More specifically, the objectives of the internship will be as follows:

- Create phantoms with inclusions of different sizes and stiffness, using different materials.
- Perform multi-frequency MRE experiments on a preclinical 7T MRI scanner
- Optimize the parameter settings for the reconstruction of biomechanical properties using the NLI method: subzone size, mesh resolution, boundary conditions, etc.
- Reconstruct the viscoelastic properties of these samples using the NLI method and the reference method, and conclude on the potential of the NLI method.
- Verify and compare the viscoelastic behavior of agarose and plastisol according to rheological laws.

Skills in biomechanics and MATLAB programming for data processing are required. Knowledge in MRI physics would be appreciated and an affinity for experimental measurements is desirable.

**References**:
1. Asbach P, Klatt D, Hamhaber U, et al. Assessment of liver viscoelasticity using multifrequency MR elastography. Magnetic Resonance in Medicine. 2008;60(2):373-379.

2. Oliphant TE, Manduca A, Ehman RL, Greenleaf JF. Complex-valued stiffness reconstruction for magnetic resonance elastography by algebraic inversion of the differential equation. Magnetic Resonance in Medicine. 2001;45(2):299-310.

3. Three-dimensional subzone-based reconstruction algorithm for MR elastography, EEW Van Houten _et al._, Magnetic Resonance in Medicine, 45(5), pp. 827—837, 2001.

4. Viscoelastic power law parameters of in vivo human brain estimated by MR elastography, J Testu _et al._, Journal of the mechanical behavior of biomedical materials, 74, pp. 333—341, 2017.

5. P. Sango-Solanas et al. Parametrization of multi-frequency non-linear inversion reconstruction on in vivo mouse liver magnetic resonance elastography data, ITEC 2024.

**Supervision**:
Pilar SANGO-SOLANAS and Kevin TSE VE KOON: MCUs at Université de Lyon 1, Laboratory CREATIS

Elijah VAN HOUTEN: Professor at Université de Sherbrooke

**Application**:
**Job Type**: Internship
Contract length: 6 months

Pay: 500.00€ - 700.00€ per month

Work Location: In person

Expected Start Date: 01/02/2025