Quantifying uncertainty in diffusion MRI: a comparative study at different magnetic fields

Motivation: Diffusion MRI (dMRI) is a very noisy MRI technique. The low signal-to-noise ratio introduces uncertainties in diffusion metrics and structural connectivity measures. Goal(s): We searched for a method to investigate the uncertainty in dMRI measurements and to compare them across different magnetic field strengths. Approach: We assessed uncertainties using wild and residual bootstrapping techniques in a group of 7 healthy subjects undergoing optimized acquisition protocols at 1.5T, 3T, and 7T. Results: 7T diffusion metrics and uncertainties are comparable with 3T and exhibited significant differences with 1.5T. The enhanced 7T spatial resolution demonstrated capabilities in representing structural connectivity with greater complexity and reduced uncertainty. Impact: The findings support the hypothesis that 7T dMRI can offer new insights into structural connectivity and may be particularly valuable for single-subject studies, thanks to its ability to detect more connections and reduce uncertainty compared to clinical fields.