Numerical estimation of relaxation and diffusion distributions in two dimensions

Mitchell, Jonathan; Chandrasekera, Thusara C.; Gladden, Lynn F.

doi:10.1016/j.pnmrs.2011.07.002

Cited by 169 publications

(137 citation statements)

References 42 publications

Supporting

Mentioning

124

Contrasting

Unclassified

Order By: Relevance

“…(5), each component with specific values of D ⊥ and D ∥ gives rise to a ridge in the 2D distribution PðD zz ; D iso Þ. A collection of such ridges is challenging to reproduce with the standard 2D ILT algorithms due to inversion artifacts [12,58]. In order to circumvent this problem, we introduce the distribution PðD ⊥ ; D ∥ Þ where each distinct component gives rise to a 2D delta function.…”

mentioning

confidence: 99%

Two-Dimensional Correlation of Isotropic and Directional Diffusion Using NMR

Martins

Topgaard

2016

Phys. Rev. Lett.

View full text Add to dashboard Cite

Diffusion nuclear magnetic resonance (NMR) is a powerful technique for studying porous media, but yields ambiguous results when the sample comprises multiple regions with different pore sizes, shapes, and orientations. Inspired by solid-state NMR techniques for correlating isotropic and anisotropic chemical shifts, we propose a diffusion NMR method to resolve said ambiguity. Numerical data inversion relies on sparse representation of the data in a basis of radial and axial diffusivities. Experiments are performed on a composite sample with a cell suspension and a liquid crystal. DOI: 10.1103/PhysRevLett.116.087601 Many porous materials of biological, geological, and synthetic origin contain water in a range of microscopic environments with different local pore geometries. Information about the structure of the pore space can be inferred from nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) measurements of the self-diffusion of the pore water [1,2]. The diffusion MRI approach has been especially powerful for noninvasive studies of the living human brain [3], allowing for quantification of axon diameter [4], mean orientation [5], and orientation distribution [6]. Although useful, classical diffusion MRI protocols relying on the Stejskal-Tanner experiment [7] suffer from the fact that the effects of distributions in pore size, anisotropy, and orientation are intrinsically entangled. A partial solution to this problem is provided by the double diffusion encoding (DDE) family of NMR methods [8], which can give estimates of the pore size and shape even in the presence of orientational disorder [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Current in vivo versions of DDE permit detection of anisotropy in areas of the human brain that are macroscopically isotropic [24] and the assignment of metabolitespecific compartment shapes in animal models [25]. Despite these impressive feats, DDE yields ambiguous results if the investigated volume element comprises several types of water environments, the presence of which has been inferred by fitting multicomponent biophysical models [26][27][28][29] to in vivo data acquired with the StejskalTanner method [30,31]. Selection of a single model from all the ones that are able to reproduce the experimental data remains a challenge [29]. The key to future progress in diffusion NMR and MRI of heterogeneous anisotropic materials lies in designing a method to unambiguously resolve and quantify water compartments with respect to their size and anisotropy, irrespective of the details of their orientations. Once this goal has been achieved, the obtained information could be used as input for existing methods to estimate distributions of axon diameters [4] and orientations [32][33][34].In solid-state NMR spectroscopy [35], the eigenvalues and eigenvectors of the chemical shift tensors can be determined through the dependence of the nuclear spin Hamiltonian on the orientation of the tensors with respect to the static magnetic field. We have recently poin...

show abstract

mentioning

confidence: 99%

Two-Dimensional Correlation of Isotropic and Directional Diffusion Using NMR

Martins

Topgaard

2016

Phys. Rev. Lett.

View full text Add to dashboard Cite

show abstract

“…However, with progressive hydration a multi-exponential behavior was developed, which was resolved by means of an inversion algorithm based on Tikhonov regularization [20,21]. For a review of these methods in NMR spectroscopy see [22]. The applied algorithm is designed to choose automatically the optimal value of the regularization parameter in order to derive a continuous, constrained and smooth distribution of relaxation times that have a physical basis compatible with the pore-size distribution of the system.…”

Section: Methodsmentioning

confidence: 99%

“…This is best seen in Fig. 4, which illustrates NMR relaxation data of water confined into the cement pores, and the corresponding T 1 distribution profiles g(T 1 ) obtained by the Tikhonov regularization method [20][21][22]. At early hydration stage (blue curve) water is characterized by a single relaxation mechanism, whereas at late hydration times a doubly peaked relaxation profile is observed (black curve).…”

Section: H Nmr Spin-lattice T 1 Relaxation Time Experimentsmentioning

confidence: 97%

See 1 more Smart Citation

Pore structure evolution and strength development of G-type elastic oil well cement. A combined 1H NMR and ultrasonic study

Karakosta

Lagkaditi

El-Hardalo

et al. 2015

Cement and Concrete Research

View full text Add to dashboard Cite

“…The field of two-dimensional relaxation-diffusion distributions was also reviewed. 86 Rios and co-workers 87 explored the application of partial least squares regression to rock permeability predictions from 1 H NMR transverse relaxation data. Venkataramanan and co-workers 88 provided a theoretical basis for estimating the moments of T 2 distributions in grossly inhomogeneous field.…”

Section: Experimental Aspectsmentioning

confidence: 99%

Nuclear spin relaxation in liquids and gases

Kowalewski¹

2013

Nuclear Magnetic Resonance

View full text Add to dashboard Cite

This report reviews the progress in the field of NMR relaxation in fluids. The emphasis is on comparatively simple liquids and solutions of physico-chemical and chemical interest, in analogy with the previous periods, but selected biophysicsrelated topics and relaxation-related work on more complex systems (macromolecular solutions, liquid crystalline systems, glassy and porous materials) are also covered. The period under review is from June 2011 through May 2012. Some earlier works, overlooked in last year's chapter, are also included. The outline of this chapter is as follows: section 2 which follows the introduction covers the general, physical and experimental aspects of nuclear spin relaxation in liquids and is further divided in seven subsections. The first two are fairly general and the following three discuss more specific aspects of spin-1/2 systems. The last two subsections cover quadrupolar nuclei and paramagnetic systems, respectively. Section 3 deals with applications of NMR relaxation in liquids, starting with pure liquids and continuing with solutions of low-molecular weight compounds. It also includes a selection of works on solutions of biological macromolecules and other complex systems. The progress in the field of relaxation in gases is described in section 4.

show abstract

Numerical estimation of relaxation and diffusion distributions in two dimensions

Cited by 169 publications

References 42 publications

Two-Dimensional Correlation of Isotropic and Directional Diffusion Using NMR

Two-Dimensional Correlation of Isotropic and Directional Diffusion Using NMR

Pore structure evolution and strength development of G-type elastic oil well cement. A combined 1H NMR and ultrasonic study

Nuclear spin relaxation in liquids and gases

Contact Info

Product

Resources

About