Mapping of Microscopic Diffusion Anisotropy Measures in the Living Human Brain

Marco Lawrenz¹, ², Jrgen Finsterbusch¹, ²

Double-wave-vector diffusion-weighting experiments with two weighting periods applied successively offer access to microscopic tissue. Thus, they may help to overcome confounds of DTI, e.g. in white matter fibre crossings. But so far, only the angular signal modulation that reflects the presence of microscopic diffusion anisotropy has been detected in vivo. This study extends present experiments to determine rotationally invariant measures of the microscopic diffusion anisotropy introduced recently. With the dedicated direction combination schema experimental signal variations could be reduced which improves the reliability of the measures. Additionally, the rotational invariance and the applicability in full brain white matter are demonstrated.