Validation of Diffusion Tensor Imaging Measures of Corticocortical Connectivity in the Brain
Diffusion tensor imaging (DTI) provides a unique approach to probing the microstructure of biological tissues noninvasively and DTI-based tractography is an irreplaceable tool to measure anatomical connectivity in human brain in vivo. However, due to the limitations of DTI techniques and tractography algorithms, tracked pathways might not be completely accurate. Thus, quantifying the agreement between DTI tractography and histological measurements of true fiber pathways is critical for progress in the field. A series of validation studies of DTI tractography is presented in this thesis, including (1) assessment of the relationship between DTI tractography-derived corticocortical connectivity and histological 'ground truth' on a regional and voxelwise basis; (2) localizing the divergence between DTI tractography and histology, followed by qualitative analysis of the reasons for those discrepancies. The work presented here is based on a non-human primate animal model, which has comparable parameters to magnetic resonance imaging (MRI) human data, and thus provides an important guide to interpreting the results of DTI-based tractography measures in the human brain.