Simultaneous Diffusion and T1 Weighted Contrast Imaging for Human Brain Mapping

Introduction: Diffusion tensor imaging (DTI) is typically obtained by echo-planar imaging (EPI) to map the human brain. However, EPI is sensitive to susceptibility effects, requiring elaborate image post-processing. Besides, DTI alone is limited in assessing gray and white matter boundaries of the brain, which has important implications for obtaining accurate images from brain atrophy. This study aimed to design and evaluate simultaneous diffusion and T1 weighting high- resolution imaging for human brain mapping. Material and Methods: The method of T1 weighted three-dimensional Magnetization-prepared rapid gradient-echo (T1w 3D MPRAGE), which is conventionally used for structural brain mapping of gray and white matter, was extended to incorporate diffusion encoding using simulation and experiment to develop high-resolution DTI and T1-weighted human brain data. Results: Theoretical simulations, as well as experimental results from in-vivo human brain studies at 4 Tesla magnetic field strength, showed that the DTI contrast, including fractional anisotropy (FA) and mean diffusivity (MD), incorporated into T1w 3D MPRAGE improves the contrast between gray and white matter sub-structural boundaries. Moreover, diffusion encoding into 3D MPRAGE avoids the inherent image distortions typically seen in EPI-based DTI. Conclusion: This study suggests the capability and effectiveness of the combined DTI weighted 3D MPRAGE and T1 weighted for improving the detection of gray/white matter boundaries in human brain imaging.