Real-space imaging of macroscopic diffusion and slow flow by singlet tagging MRI

Pileio, Giuseppe; Dumez, Jean‐Nicolas; Pop, Ionut-Alexandru; Hill-Cousins, Joseph T.; Brown, Richard C. D.

doi:10.1016/j.jmr.2015.01.016

Cited by 57 publications

(65 citation statements)

References 26 publications

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“…This finding is in line with an earlier report of 1 H T S for an asymmetric maleate diester, 1‐(ethyl‐d 5 ),4‐(propyl‐d 7 )( Z )‐but‐2‐enedioate, in carefully degassed conditions . It was subsequently assumed that plastic tubing allowed oxygen to penetrate into the sample region . An improvement in oxygen removal over our current setup would have to be achieved by a factor of 10–20 to reveal the next biggest contribution to R S , which is the intramolecular proton deuterium dipolar relaxation (

R_{normalS}^{normalD, i n t r a}

) for DMF‐d 6 and the symmetric CSA mechanism (

R_{normalS}^{Δ σ^{+}}

) for DMM‐d 6 .…”

Section: Figuresupporting

confidence: 91%

Limits in Proton Nuclear Singlet‐State Lifetimes Measured with para‐Hydrogen‐Induced Polarization

et al. 2016

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The synthesis of a hyperpolarized molecule was developed, where the polarization and the singlet state were preserved over two controlled chemical steps. Nuclear singlet-state lifetimes close to 6 min for protons are reported in dimethyl fumarate. Owing to the high symmetry (AA'X X ' and A systems), the singlet-state readout requires either a chemical desymmetrization or a long and repeated spin lock. Using DFT calculations and relaxation models, we further determine nuclear spin singlet lifetime limiting factors, which include the intramolecular dipolar coupling mechanism (proton-proton and proton-deuterium), the chemical shift anisotropy mechanism (symmetric and antisymmetric), and the intermolecular dipolar coupling mechanism (to oxygen and deuterium). If the limit of paramagnetic relaxation caused by residual oxygen could be lifted, the intramolecular dipolar coupling to deuterium would become the limiting relaxation mechanism and proton lifetimes upwards of 26 min could become available in the molecules considered here (dimethyl maleate and dimethyl fumarate).

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R_{normalS}^{normalD, i n t r a}

) for DMF‐d 6 and the symmetric CSA mechanism (

R_{normalS}^{Δ σ^{+}}

) for DMM‐d 6 .…”

Section: Figuresupporting

confidence: 91%

Limits in Proton Nuclear Singlet‐State Lifetimes Measured with para‐Hydrogen‐Induced Polarization

et al. 2016

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“…Hyperpolarisation storage, combined with on-demand accessibility, suggests the use of singlet order as a repository of hyperpolarisation from where the signal enhancement gained by a given hyperpolarisation technique can be repeatedly accessed over a long time (tens of minutes) [12]. The long lifetime of singlet order has also been used to study slow motions like diffusion [13,14,15,16,17], flow [17], molecular dynamics [18,19] and ligand binding [20,21,22,23].…”

Section: Introductionmentioning

confidence: 99%

“…Significant studies on the chemical requirements for obtaining long-lived spin order have been also conducted [17,51,52,53,54] with a record lifetime of 70 min for a 13 C-pair [54], 26 min for a 15 N-pair [51], and 10 min for a 1 H-pair [17] demonstrated. The potential use of singlet order in MRI has been discussed and demonstrated [55,12,56,43,17,57]. This paper focuses on the efforts of the author and other groups spent in devising methods to access and manipulate singlet order in systems made by two spins-1/2.…”

Section: Introductionmentioning

confidence: 99%

Singlet NMR methodology in two-spin-1/2 systems

Pileio

2017

Progress in Nuclear Magnetic Resonance Spectroscopy

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This paper discusses methodology developed over the past 12 years in order to access and manipulate singlet order in systems comprising two coupled spin-1/2 nuclei in liquid-state nuclear magnetic resonance. Pulse sequences that are valid for different regimes are discussed, and fully analytical proofs are given using different spin dynamics techniques that include product operator methods, the single transition operator formalism, and average Hamiltonian theory. Methods used to filter singlet order from byproducts of pulse sequences are also listed and discussed analytically. The theoretical maximum amplitudes of the transformations achieved by these techniques are reported, together with the results of numerical simulations performed using custom-built simulation code.

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“…The existence of such states creates many new possibilities in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) experiments, including the study of slow transport processes such as slow flow and diffusion 12 , as well as the storage of hyperpolarized nuclear spin order for relatively long times 13,14 .…”

Section: Introductionmentioning

confidence: 99%

Prediction of low-field nuclear singlet lifetimes with molecular dynamics and quantum-chemical property surface

Håkansson

2017

Phys. Chem. Chem. Phys.

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Molecular dynamics and quantum chemistry methods are implemented to quantify nuclear spin-1/2 pair singlet-state relaxation rates for three molecular systems at low magnetic field and room temperature. Computational methodology is developed for weak interactions, particularly important for singlet states at low field. These include spin-rotation and spin-internal-motion effects, which describe the coupling of the spin-carrying nuclei to fluctuating local magnetic fields induced by the overall and internal molecular fluctuations, respectively. A high-dimensional tensor property surface using Kriging interpolation is developed to circumvent costly quantum-chemical calculations. Together with the intramolecular dipolar relaxation, all the simulated relaxation mechanisms are accounted for with a common theoretical framework. Comparison with experiment indicates that quantitative accuracy is obtained, sufficient to enable guidance in the molecular design of molecules with long-lived singlet order.

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Real-space imaging of macroscopic diffusion and slow flow by singlet tagging MRI

Cited by 57 publications

References 26 publications

Limits in Proton Nuclear Singlet‐State Lifetimes Measured with para‐Hydrogen‐Induced Polarization

Limits in Proton Nuclear Singlet‐State Lifetimes Measured with para‐Hydrogen‐Induced Polarization

Singlet NMR methodology in two-spin-1/2 systems

Prediction of low-field nuclear singlet lifetimes with molecular dynamics and quantum-chemical property surface

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