Diffusion artefact appearance in MRI with ultra-high spatial resolution

Motivation: Effect of free diffusion introduced image blur is well known but measurable samples always have solid boundaries which results in non-blur like artefacts in ultra-high-resolution images. Goal(s): Demonstration of diffusion introduced artefact behavior near impermeable barriers. Approach: A Monte Carlo simulation of particles undergoing a random walk was performed and CTI specific point spread functions (PSFs) and 1D images determined. Results: It was demonstrated that the PSF yields asymmetric blur and signal enhancement in direct vicinity of the barrier. Simulations clearly indicating the PSF to be dependent on spatial resolution and gradient strength. Impact: These results will help to prohibit misinterpretation of MR images of small structures with ultra-high-resolution MRI.