Impacts of diffusion MRI spatial resolutionon on the short-range association fiber reconstruction and connectivity estimation

Motivation: Short-range association fibers (SAFs) are essential for mediating cortico-cortical communication. However, their accurate mapping requires high-resolution diffusion MRI data since SAFs reside in a ~1.5mm thin layer beneath the cortex. Goal(s): Clarify impact of diffusion image resolution on the estimation of SAFs and connectivity. Approach: Simulated and empirical diffusion data at different resolutions were obtained for reconstructing structural connectivity matrices. SAF connectivity strength was quantified and compared. The volume fraction and fiber orientation of local SAFs were examined. Results: Lower image spatial-resolution leads to disorganized SAF orientation, decreased voxel-wise white matter volume fraction, and underestimation of SAF connectivity strength. Impact: This study demonstrates the poor reconstruction result of SAFs at low resolution, emphasizing the need for high-resolution diffusion imaging for accurately SAF modeling. The gSlider protocol presented in the study could be an ideal choice for SAFs research.