Quantification of microscopic diffusion anisotropy disentangles effects of orientation dispersion from microstructure: Applications in healthy volunteers and in brain tumors

• DOI: 10.1016/j.neuroimage.2014.09.057
• Publication Date: 2014-10-04T06:53:40Z
• Authors: Filip Szczepankie...; Samo Lasič; Danielle van Westen; Pia C. Sundgren; Elisabet Englund; Carl-Fredrik Westin; Freddy Ståhlberg; Jimmy Lätt; Daniel Topgaard; Markus Nilsson
• Keywords: q-vector; Adult; Male; Microscopic fractional anisotropy; Radiology and Medical Imaging; Cognitive Neuroscience; 03 medical and health sciences; Microscopic; 0302 clinical medicine; Magic angle spinning of the; Image Processing, Computer-Assisted; Humans; Computer Simulation; 14. Life underwater; Gray Matter; 10. No inequality; Brain Neoplasms; Brain; Diffusion weighted imaging; Middle Aged; Microscopic anisotropy; Magic angle spinning of the q-vector; White Matter; Diffusion Tensor Imaging; Neurology; Anisotropy; Female; Glioblastoma; Meningioma; Order parameter; fractional anisotropy; Radiology, Nuclear Medicine and Medical Imaging

The anisotropy of water diffusion in brain tissue is affected by both disease and development. This change can be detected using MRI often quantified the fractional (FA) derived from tensor imaging (DTI). Although FA sensitive to anisotropic cell structures, such as axons, it also their orientation dispersion. a major limitation use biomarker for "tissue integrity", especially regions complex microarchitecture. In this work, we seek circumvent disentangling effects microscopic (μFA) order parameter (OP) were calculated contrast between signal prepared with directional isotropic encoding, where latter was achieved magic angle spinning q-vector (qMAS). These parameters healthy volunteers two patients; one patient meningioma glioblastoma. Finally, used simulations elucidate relation μFA various micro-architectures. Generally, high white matter low gray matter. matter, largest differences found crossing interfaces large tracts, while low. Both tumor types exhibited FA, which glioblastoma, indicating that contained disordered glioblastoma did not. interpretation confirmed histological examination. We conclude DTI reflects amount suggest OP may complement independently quantifying level coherence.