Inversion Recovery-Prepared Q-Space Trajectory Imaging of the Human Brain

Motivation: Partial volume (PV) effects can distort the quantification of brain microstructure in advanced diffusion-weighted MRI. Goal(s): To examine PV effects on microparameters measured via Q-space trajectory imaging (QTI) on a clinical MR scanner. Approach: We selectively suppressed fluid, white and grey matter signals by inversion recovery preparation. Results: QTI-derived microparameters modulate distinctly with different inversion times in the targeted regions. Grey brain matter shows non-vanishing microscopic anisotropy when the white matter signal is suppressed. We also identified PV between brain tissue and cerebrospinal fluid as the major source of contrast in the mean diffusivity variance coefficient $cMD$. Impact: Partial volume effects substantially impact the value distribution of QTI-derived microparameters in the human brain. Inversion recovery preparation could improve the accuracy and interpretability of such parameters. IR-QTI may therefore advance the microstructural characterization of healthy and diseased tissue.