Thesis: Imagerie de la myéline par IRM à temps d’écho ultracourt

PhD defense : Lucas SOUSTELLE

Teams : IMAGeS - IMIS

Title : Imagerie de la myéline par IRM à temps d’écho ultracourt

Abstract : Non-invasive evaluation of white matter myelin in the central nervous system is essential for the monitoring of pathologies such as multiple sclerosis. Myelin is essentially composed of lipids and proteins: because of the numerous interactions between these macromolecules, the transverse relaxation times are very short (T2 < 1 ms), and their signals are undetectable using conventional sequences.
Standard MRI methods for the characterization of myelin rely on the modeling of the interactions of aqueous protons with myelinated structures. Nonetheless, the selectivity and robustness of such indirect methods are questionable.
Ultrashort echo time sequences (UTE – TE < 1 ms) may allow to directly detect the signals arising from the semi-solid spin pool of myelin. The main objective of this thesis consists in developing such methods in order to generate a positive and selective contrast of myelin using a preclinical imaging system. Validation of each method was carried out using an ex vivo murine model by confronting healthy and demyelinated animals. Results show a significant selectivity of the UTE methods to demyelination, suggesting that the technique is promising for white matter myelin monitoring.

The jury is comprised of Mr Jean-Paul ARMSPACH, research engineer HDR at the university of Strasbourg (Examiner), Mr François ROUSSEAU, Professor at the IMT Atlantique of Brest (Examiner), Mr Alexandre VIGNAUD, research engineer HDR at the CEA of Saclay (Reviewer), Mr Sylvain MIRAUX, senior researcher at the university of Bordeaux (Reviewer), Mrs Virginie CALLOT, senior researcher at the university of Aix-Marseille (Examiner) and Mr Paulo LOUREIRO de SOUSA, research engineer CNRS HDR at the university of Strasbourg (Examiner).

The defense will be held in French on Wednesday,  Mai 16th, at 9:00 in the Ruch amphitheater at the faculty of dental surgery.