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Isotropic diffusion weighting in PGSE NMR by magic-angle spinning of the q-vector.

Eriksson, Stefanie LU ; Lasic, Samo LU and Topgaard, Daniel LU (2013) In Journal of Magnetic Resonance 226. p.13-18
Abstract
When PGSE NMR is applied to water in microheterogeneous materials such as liquid crystals, foodstuffs, porous rocks, and biological tissues, the signal attenuation is often multi-exponential, indicating the presence of pores having a range of sizes or anisotropic domains having a spread of orientations. Here we modify the standard PGSE experiment by introducing low-amplitude harmonically modulated gradients, which effectively make the q-vector perform magic-angle spinning (MAS) about an axis fixed in the laboratory frame. With this new technique, denoted q-MAS PGSE, the signal attenuation depends on the isotropic average of the local diffusion tensor. The capability of q-MAS PGSE to distinguish between pore size and domain orientation... (More)
When PGSE NMR is applied to water in microheterogeneous materials such as liquid crystals, foodstuffs, porous rocks, and biological tissues, the signal attenuation is often multi-exponential, indicating the presence of pores having a range of sizes or anisotropic domains having a spread of orientations. Here we modify the standard PGSE experiment by introducing low-amplitude harmonically modulated gradients, which effectively make the q-vector perform magic-angle spinning (MAS) about an axis fixed in the laboratory frame. With this new technique, denoted q-MAS PGSE, the signal attenuation depends on the isotropic average of the local diffusion tensor. The capability of q-MAS PGSE to distinguish between pore size and domain orientation dispersion is demonstrated by experiments on a yeast cell suspension and a polydomain anisotropic liquid crystal. In the latter case, the broad distribution of apparent diffusivities observed with PGSE is narrowed to its isotropic average with q-MAS PGSE in a manner that is analogous to the narrowing of chemical shift anisotropy powder patterns using magic-angle sample spinning in solid-state NMR. The new q-MAS PGSE technique could be useful for resolving size/orientation ambiguities in the interpretation of PGSE data from, e.g., water confined within the axons of human brain tissue. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Magnetic Resonance
volume
226
pages
13 - 18
publisher
Elsevier
external identifiers
  • wos:000314190700002
  • pmid:23178533
  • scopus:84869888296
ISSN
1096-0856
DOI
10.1016/j.jmr.2012.10.015
language
English
LU publication?
yes
id
fc7477f3-203a-469f-b1fb-86d53099cd5c (old id 3218528)
date added to LUP
2012-12-14 12:14:25
date last changed
2019-03-17 04:04:22
@article{fc7477f3-203a-469f-b1fb-86d53099cd5c,
  abstract     = {When PGSE NMR is applied to water in microheterogeneous materials such as liquid crystals, foodstuffs, porous rocks, and biological tissues, the signal attenuation is often multi-exponential, indicating the presence of pores having a range of sizes or anisotropic domains having a spread of orientations. Here we modify the standard PGSE experiment by introducing low-amplitude harmonically modulated gradients, which effectively make the q-vector perform magic-angle spinning (MAS) about an axis fixed in the laboratory frame. With this new technique, denoted q-MAS PGSE, the signal attenuation depends on the isotropic average of the local diffusion tensor. The capability of q-MAS PGSE to distinguish between pore size and domain orientation dispersion is demonstrated by experiments on a yeast cell suspension and a polydomain anisotropic liquid crystal. In the latter case, the broad distribution of apparent diffusivities observed with PGSE is narrowed to its isotropic average with q-MAS PGSE in a manner that is analogous to the narrowing of chemical shift anisotropy powder patterns using magic-angle sample spinning in solid-state NMR. The new q-MAS PGSE technique could be useful for resolving size/orientation ambiguities in the interpretation of PGSE data from, e.g., water confined within the axons of human brain tissue.},
  author       = {Eriksson, Stefanie and Lasic, Samo and Topgaard, Daniel},
  issn         = {1096-0856},
  language     = {eng},
  pages        = {13--18},
  publisher    = {Elsevier},
  series       = {Journal of Magnetic Resonance},
  title        = {Isotropic diffusion weighting in PGSE NMR by magic-angle spinning of the q-vector.},
  url          = {http://dx.doi.org/10.1016/j.jmr.2012.10.015},
  volume       = {226},
  year         = {2013},
}