Review of Magnetic Resonance Imaging with Application to Neural Tissue Tractography

Magnetic resonance imaging (MRI) provides an exquisitely probe of neural tissue structure in vivo. In this paper, the foundations and characteristics of different imaging approaches are reviewed, such as diffusion tensor imaging (DTI), Q-space imaging (QSI), high angular resolution diffusion imaging (HARDI) and Q-ball imaging (QBI), and so on. Wherein, the basic theory, visualization, and reconstruction technology of DTI and QBI method are more cared. With the fact that water diffusion is sensitive to the tissue microstructure, DTI is often used in assessing the orientation and integrity of neural fibers, but it depends on the tensor model heavily, and also assumes homogeneous diffusion within each voxel at the same time. So it is invalid in resolving the complex intravoxel tissue structure including fiber bundling, intersecting and divergence. In order to complement the limitation of DTI, a model independent way named q-space is developed. However, this technique suffers from time-intensive problem during signal sampling. Therefore, a spherical sampling based alternative approach named QBI is finally evaluated and recommended because of its´ benefits as model independent, linearity in signal and computation simplicity.