Magnetic Resonance Imaging (MRI) Sequences Optimization in Healthy Subjects

Magnetic resonance imaging (MRI) is a noninvasive and non-ionizing (no use of X-rays) imaging modality. Today it is considered an anatomical and functional exploration reference technique. Since its inception around 1985, this technology is constantly evolving. Many advances in MRI require constant adaptations of radiological practices. The morphological image is now associated with functional and parametric information (infusion, diffusion spectroscopy, etc ...). In parallel, work combining acquisition and post-processing of data also open new applications (tractography, functional MRI, etc ....). Thus, more and more procedures are necessary to "integrate" these techniques for the diagnosis and adapt to new demands of clinicians. The type of sequence and its associated parameters allow to directly influence the contrast of images, to characterize tissue compared to another and, ultimately, to highlight morphological or functional abnormality. Image quality can be optimized on each MRI, depending on the time available for the acquisition on the one hand, and on the desired resolution and contrast, on the other hand. For each sequence, it is therefore necessary to find a compromise that will optimize the diagnostic quality of the examination. This optimization requires a phase focusing on healthy volunteers. It is therefore important that researchers and physicists could design on healthy volunteers, the best settings of all parameters for an image or spectrum. Indeed, it is always necessary to properly optimize every parameter choices before beginning a study of a cohort of patients. In this context, the main objective of this study is to optimize sequences and imaging protocols to evaluate and validate the choice of parameters in healthy volunteers.