Yuxi Pang1
1Dept. of Radiology, University of Michigan, Ann Arbor, MI, United States
1Dept. of Radiology, University of Michigan, Ann Arbor, MI, United States
Anisotropic R2 and R2* relaxation has been documented in white matter, yet the
underlying relaxation mechanisms still remain not well understood. This work is
to propose a generalized magic angle effect model to better
characterize the reported anisotropic transverse relaxation.
FIGURE 2. Measurements and modeling of anisotropic $$$R_2$$$ in the human
brain white matter in vivo at 3T. The measured
(black triangle) and the fitted anisotropic myelin water $$$R_2$$$ (2A) and
intra- and extracellular (IE) water $$$R_2$$$ (2B) using
the gMAE model with a phase offset $$$φ_0$$$ (Fit A, solid red lines), and the previous model (Fit B, dashed blue lines) without $$$φ_0$$$ from the
original publication [REF. 2]. The fitting residuals, defined as $$$ΔR_2$$$=Fitted-Measured, are respectively shown for myelin water (2C) and IE water (2D).
FIGURE 3. A schematic of water molecular restricted rotational diffusion (3A) and anisotropic translational diffusion (3B) in the human brain white matter.