These 2019 EN

Title:

Mapping the electrical properties of the brain with MRI

Supervisors:

Dr Paulo LOUREIRO de SOUSA (Lab. ICube, Université de Strasbourg)

Dr Stéphanie SALMON (Laboratoire de Mathématiques de Reims, Université de Reims)

Co-supervisor: Dr Julien LAMY (Lab. ICube, Université de Strasbourg)

Scientific context:

Scientist or engineer, with a strong background in physics (electromagnetism). The candidate should also have good scientific programming skills.

Salary:

1,400€/month approximately, via a Doctoral Research Contract. This is a three-year contract offered by the University of Strasbourg; it is awarded after a selection organized by the Doctoral School “Mathématiques, Sciences de l'Information et de l'Ingénieur (MSII)”.

Hosting labs:

• ICube : Laboratoire des sciences de l’Ingénieur, de l’Informatique et de l’Imagerie, UMR 7357 Université de Strasbourg / CNRS
  

Equipe IMIS, Imagerie Multimodale Intégrative en Santé

• Laboratoire de Mathématiques de l’université de Reims-Champagne-Ardenne

Scientific context:

Several studies have shown that some diseases cause local changes in the electrical properties (EP) of biological tissues: increased values of electrical conductivity have been reported in brain tumors; significant changes in EP values have also been reported in brain tissue in relation to stroke; local ischemia and the swelling of cells which occur due to a focal seizure during epilepsy can also alter the electrical properties. In vivo EP mapping would therefore provide relevant information regarding the health status of the tissue. To date, no method can accurately and rapidly estimate, in a non-invasive manner, the distribution of EP of the brain in humans.

Nuclear Magnetic Resonance Imaging (MRI) is a versatile medical imaging modality which can collect a great deal of information on the bio-physical properties of tissues. Because of its underlying electromagnetic principles, MRI is a logical approach to non-invasively map tissue EP in vivo and in humans.

The objective of this thesis proposal is to evaluate the feasibility of mapping the electrical properties of the human brain, in vivo, by MRI. This project also aims to better understand the relationship between tissue, cell changes and EP, measured at different frequencies. One of the original aspects of this project is the close collaboration between acquisition, image processing, and numerical simulations of the direct and inverse problems of electromagnetic propagation phenomena. To reduce scan time and increase image quality, fast acquisition methods will be explored. New strategies will be used to improve the stability and robustness of reconstructions of electrical parameter maps, such as the integration of a priori knowledge. A mathematical sensitivity analysis can be conducted to better understand the influence of the EP on the acquired measurements and thus make it possible to quantify the errors.

Laboratoires d'accueil :

Cette thèse de doctorat sera réalisée au sein du laboratoire des sciences de l'ingénieur, de l'informatique et de l'imagerie (ICube), sur le site de l’Hôpital Civil, dans l’équipe « Imagerie Multimodale Intégrative en Santé » en collaboration avec le Laboratoire de Mathématiques de l’université de Reims-Champagne-Ardenne. Le laboratoire ICube a une large expérience dans le développement de méthodologie IRM, pour des applications en recherche clinique, principalement en neurologie, mais également pour des applications en imagerie interventionnelle. Disposant de trois scanners IRM dédiés à la recherche chez l’Homme (1.5T et 3T SIEMENS) et chez le petit animal (7T Bruker), les travaux en méthodologie du laboratoire ICube se focalisent essentiellement sur les questions liées aux méthodes d’acquisition des données et aux reconstructions des cartes de propriétés des tissus biologiques.

Le Laboratoire de Mathématique de Reims (LMR) regroupe des experts en mathématiques : analyse, algèbre et mathématiques appliquées. Les membres de l’équipe de mathématiques appliquées du LMR sont impliquées depuis longtemps dans des projets orientés médecine (ANR VIVABRAIN et MAIA) et travaillent en particulier sur les simulations numériques des phénomènes d’électromagnétisme et sur les problèmes inverses.

Application:

To apply, please send CV, cover letter, and grades and rank of Master’s degree to ploureiro@unistra.fr .

References:

Voigt, T., Katscher, U., & Doessel, O. (2011). Quantitative conductivity and permittivity imaging of the human brain using electric properties tomography. Magnetic Resonance in Medicine, 66(2), 456-466.

Katscher, U., Kim, D. H., & Seo, J. K. (2013). Recent progress and future challenges in MR electric properties tomography. Computational and mathematical methods in medicine, 2013.

Zhang, X., Liu, J., & He, B. (2014). Magnetic-resonance-based electrical properties tomography: a review. IEEE reviews in biomedical engineering, 7, 87-96.

Katscher, U., & van den Berg, C. A. (2017). Electric properties tomography: Biochemical, physical and technical background, evaluation and clinical applications. NMR in Biomedicine, 30(8), e3729