Collections > UNC Chapel Hill Undergraduate Honors Theses Collection > A Framework for Diffusion Fiber-based Analysis of T1w/T2w Ratio Maps

Purpose: To develop, test, evaluate and apply a novel tool for the diffusion fiber-based analysis of T1w/T2w ratio maps quantifying myelin content. Background: The cerebral white matter in the human brain develops from a mostly non-myelinated state to a nearly fully mature white matter myelination within the first few years of life. The study of myelination is of interests in a number of brain development studies. High resolution T1w/T2w ratio maps are believed to be effective in quantitatively estimating myelin content on a voxel-wise basis. I propose the use of a fiber-tract-based analysis of such T1w/T2w ratio data, as it allows us to separate fiber bundles that regional analysis imprecisely groups together, and to associate effects to specific tracts rather than large, broad regions. Methods: I developed an intuitive tool to facilitate such fiber-based studies of T1w/T2w ratio maps. Via its Graphical User Interface (GUI) the tool is accessible to non-technical users. The framework uses calibrated T1w/T2w ratio maps and a prior fiber atlas as an input to generate profiles of T1w/T2w values using a version of the UNC atlas-based fiber analysis toolkit that I adapted to handle non-diffusion data. The resulting fiber profiles are used in a statistical analysis that performs along-tract functional statistical analysis. We applied this approach to a study of early brain development in neonates. Results: I implemented a publicly available tool for the fiber based analysis of T1w/T2w ratio maps and tested it in a study of brain development.