Application Of Diffusion Tensor Imaging For Fiber Tracking In Visual Pathway

Vision is the main source of receiving outside information. If there are some problems in vision, the communication between people and outside will be impacted seriously. So the research on occurrence, prevention and treatment of the visual diseases have become very important. Due to the particularity of the visual pathway in physical structure, a lot of parts can not be found through a routine eye examination. Therefore, it is necessary to use the modern medical imaging technology to study and diagnose the diseases.Diffusion tensor imaging(DTI) can measure and quantify the microstructure of the organization. Currently, it is the only non-invasive examination which can study the microstructure and morphology of the brain white matter fiber in vivo.This paper gives a description about the optic nerve, optic chiasm, optic tract, lateral geniculate body and optic radiation in the visual pathway from the anatomy and physiology in detail, and introduces a basic conception of MRI and DTI. This paper analyses the processing method of tensor, the meaning of relational parameter, the classification of diffusion pattern and some visualization method of DTI. In data acquisition, based on the impact of parameter to imaging quality, the paper analyses the parameters and selects the most suitable parameters for fiber tractography based on the imaging results. Besides, based on the SENSE of parallel reconstruction imaging, the study reduces half of the scanning time and get a good reconstruction of image. After getting the suitable parameters and data acquisition of healthy undergraduates, this study compares several data post-processing platform and find out the most appropriate platform to process the DTI data. In the process of imaging, as the optic fibers have probabilities of fiber breakage in fiber tracking, this paper abandons traditional method on selecting ROIs. This research designs a better method of selecting a single fiber as a new ROI. The unique single fiber can bi a precise, localized, long-distance ROI. The small ROI of single fiber can locating the scope of the fiber tracking and can avoid the fibers insertion of other nervous system combined with traditional regional ROI. In the end, this paper get a good separation imaging for the crossing fibers in optic chiasm and the three functional fiber bundles in optic radiation.