MRI Technique Development
Magnetic resonance imaging (MRI) has become one of the most common methods of imaging the brain. This is mainly due to the exquisite contrast it provides without the use of radiation between different tissue compartments, such as white and grey matter, as well as between healthy and pathological tissue.
Another characteristic of MRI is the possibility of manipulating nuclear spins in order to produce a large number of different image contrasts. This property not only allows the collection of several different qualitative images of the brain, but also constitutes the basis for quantitative MRI.
Quantitative MRI uses the scanner as a measurement tool to identify subtle in vivo changes that are often invisible to conventional MRI approaches. Many quantities that we would like to measure are not readily available on the scanner and need to be developed, optimised and tested for accuracy and reproducibility using healthy human volunteers and phantoms (test objects). A substantial number of the projects at CISC now use quantitative MRI techniques that have been optimised at CISC, such as quantitative magnetisation transfer, diffusion tensor imaging, T1 mapping and arterial spin labelling.
Typically, quantitative MRI techniques fit a model of the dependence of the MR signal on a physical process to a number of MRI measurements obtained at different settings of the acquisition pulse sequence, which is sensitised to the physical process of interest. Different quantitative MRI parameters can provide information about different characteristics of tissue, and, combined with clinical variables, may improve our understanding of some pathological conditions.
Dr Nick Dowell >