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Detecting compartmental non‐Gaussian diffusion with symmetrized double‐PFG MRI
Author(s) -
Paulsen Jeffrey L.,
Özarslan Evren,
Komlosh Michal E.,
Basser Peter J.,
Song YiQiao
Publication year - 2015
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.3363
Subject(s) - kurtosis , gaussian , isotropy , anisotropy , diffusion , chemistry , diffusion mri , signal (programming language) , biological system , nuclear magnetic resonance , statistical physics , computational physics , physics , optics , computer science , magnetic resonance imaging , mathematics , statistics , computational chemistry , thermodynamics , medicine , radiology , biology , programming language
Diffusion in tissue and porous media is known to be non‐Gaussian and has been used for clinical indications of stroke and other tissue pathologies. However, when conventional NMR techniques are applied to biological tissues and other heterogeneous materials, the presence of multiple compartments (pores) with different Gaussian diffusivities will also contribute to the measurement of non‐Gaussian behavior. Here we present symmetrized double PFG (sd‐PFG), which can separate these two contributions to non‐Gaussian signal decay as having distinct angular modulation frequencies. In contrast to prior angular d‐PFG methods, sd‐PFG can unambiguously extract kurtosis as an oscillation from samples with isotropic or uniformly oriented anisotropic pores, and can generally extract a combination of compartmental anisotropy and kurtosis. The method further fixes its sensitivity with respect to the time dependence of the apparent diffusion coefficient. We experimentally demonstrate the measurement of the fourth cumulant (kurtosis) of diffusion and find it consistent with theoretical predictions. By enabling the unambiguous identification of contributions of compartmental kurtosis to the signal, sd‐PFG has the potential to help identify the underlying micro‐structural changes corresponding to current kurtosis based diagnostics, and act as a novel source of contrast to better resolve tissue micro‐structure. Copyright © 2015 John Wiley & Sons, Ltd.