Magnetic resonance imaging

 The MRI Methods Research Group develops techniques for in vivo MRI, with a primary focus on characterization of anatomy and physiology, and quantitative mapping. The ability to use reproducible scanner-independent imaging markers enables new approaches in diagnostic imaging and patient follow-up after treatment. These quantitative imaging markers can be validated against more invasive reference measures, and provide volumetric non-invasive information.

This motivates our work in developing and validating such markers, and translating them for practical use in the clinical setting. Methods of interest include relaxation and magnetization transfer (MT), diffusion (DW-MRI), perfusion with dynamic contrast-enhanced (DCE-MRI) and magnetic susceptibility imaging and mapping. Currents applications include perfusion and diffusion in cancer, MT mapping in osteoarthritis, and myelin water mapping. Our group also works with clinical medical physics to integrate practical MRI techniques in the radiation therapy (RT) process, including protocol optimization, image evaluation, and integration into planning. MRI provides non-invasive imaging of the human body with excellent soft tissue contrast, which is valuable for RT treatment planning and post-RT assessment.

The MRI research group. From left to right : Stella Xing, Véronique Fortier, Ives Levesque, Mikaël Simard and Zaki Ahmed.

Key Publications

1. Alonso-Ortiz, E., Levesque, I. R. and Pike, G. B. MRI-based myelin water imaging: A technical review. Magnetic Resonance in Medicine 73(1): 70–81 (2015).
2. Rioux, J. A., Levesque, I. R. and Rutt, B. K. Biexponential Longitudinal Relaxation in White Matter: Characterization and Impact on T1 Mapping with IR-FSE and MP2RAGE. Magn Reson Med (Early View) (2015).
3. Zhang, T., Pauly, J. M. and Levesque, I. R. Accelerating parameter mapping with a locally low rank constraint. Magnetic Resonance in Medicine 73(2): 655–661 (2015).
4. Tourdias, T., Saranathan, M., Levesque, I. R., Su, J. and Rutt, B. K. Visualization of intra-thalamic nuclei with optimized white-matter-nulled MPRAGE at 7T. Neuroimage 84: 534-545 (2014).
5. Levesque, I. R., Sled, J. G. and Pike, G. B. Iterative optimization method for design of quantitative magnetization transfer imaging experiments. Magnetic Resonance in Medicine 66(3): 635-643 (2011)