Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023)

Magnetic Resonance Imaging (MRI) is very useful for examining soft tissue in the body and is still rapidly evolving in capability and increasing in use. One of the limitations of MRI is it tends to not provide exact tissue measurements, instead making relative measurements by comparing the signal in different areas. If fast and exact quantitative tissue measures could be developed for MRI, it could further its ability to offer precise information which would be valuable for medical imaging and industrial uses. Our laboratory specializes in the generation of new MRI methods by exploiting the MRI physics underlying each form of image contrast. Our long term goal is the continual development of novel methods that increase the value of MRI and are based on understanding MRI physics and its relationship to human tissue properties. This research proposal will develop new means of performing quantitative MRI, focusing on three unique quantitative techniques. The three areas of interest are emerging areas of MRI application that require further evolution to become practical tools.

The first area attempts to determine multiple quantitative MRI parameters from a minimal amount of scanning and is known as MRI fingerprinting. Similar to a detective’s use of pattern recognition to determine a physical fingerprint, we use pattern recognition of MRI evolution to determine multiple parameters at once. We will develop unique contributions in this area that make use of standard MRI sequences, which would enable immediate incorporation into standard MRI protocols, without needing lengthy additional scans. This work builds on our recent work in single parameter quantitative relaxation mapping.

The second area attempts to measure the magnetic field and then determine the actual magnetic susceptibility distribution. This area is known as Quantitative Susceptibility Mapping (QSM). The magnetic susceptibility provides a unique form of image contrast but the QSM methods are still evolving. We will work towards improving the speed, robustness and use of QSM acquisitions and processing methods to image invisible objects, blood vessels, iron, calcium and myelin.

The third area enables indirect imaging of metabolites in the brain and is known as Chemical Exchange Saturation Transfer (CEST). The method provides a means to look at chemical properties of the brain including neurotransmitter content and brain acidity. We will work to further validate these methods in comparison to spectroscopic techniques that also use MRI. This work is new to our laboratory.

The advances in all three areas will consist of new post-processing approaches, new imaging sequences, new validations of methods and new applications for human quantitative MRI. These advances will help turn these emerging MRI methods into viable tools for quantitative MRI and will provide ideal training environments for the next generation of imaging scientists.