|Title||TE dependent Diffusion Imaging (TEdDI) distinguishes between compartmental T2 relaxation times.|
|Publication Type||Journal Article|
|Year of Publication||2018|
|Authors||Veraart, J, Novikov, DS, Fieremans, E|
|ISSN||1095-9572 (Electronic); 1053-8119 (Linking)|
|Keywords||*Diffusion, *Modeling, *MRI, *Transverse relaxation|
Biophysical modeling of macroscopic diffusion-weighted MRI signal in terms of microscopic cellular parameters holds the promise of quantifying the integrity of white matter. Unfortunately, even fairly simple multi-compartment models of proton diffusion in the white matter do not provide a unique, biophysically plausible solution. Here we report a nontrivial diffusion MRI signal dependence on echo time (TE) in human white matter in vivo. We demonstrate that such TE dependence originates from compartment-specific T2 values and that it is a promising "orthogonal measure" able to break the degeneracy in parameter estimation, and to yield important relaxation metrics robustly. We thereby enable the precise estimation of the intra- and extra-axonal water T2 relaxation times, which is precluded by a limited signal-to-noise ratio when using multi-echo relaxometry alone.
bridging the micro-macro gap with diffusion MRI