From nuclear structure to the quadrupolar NMR interaction and high-resolution spectroscopy

Jerschow, Alexej

doi:10.1016/j.pnmrs.2004.12.001

Cited by 131 publications

(34 citation statements)

References 105 publications

(136 reference statements)

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“…The quadrupolar interaction arises from the electrostatic energy term involving the charge distribution of the nucleus and the electric field gradient around the nucleus [3,33,34]. The quadrupolar term is the first non-vanishing term in a series expansion, with higher order terms (hexadecapole) being negligibly small.…”

Section: Theoretical Formalism and Pulse Sequencesmentioning

confidence: 99%

“…In order to follow the sequence of events in experiments at high magnetic fields, one can follow these simple rules: [3,48]. …”

Section: Theoretical Formalism and Pulse Sequencesmentioning

confidence: 99%

“…The nuclear quadrupolar moment Q interacts with the electric field gradients (EFG) generated by the electronic distribution around the nucleus [3,33,34]. In liquids this interaction is often averaged to zero.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Sodium MRI: Methods and applications

Madelin

Lee

Regatte

et al. 2014

Progress in Nuclear Magnetic Resonance Spectroscopy

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190

209

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Sodium NMR spectroscopy and MRI have become popular in recent years through the increased availability of high-field MRI scanners, advanced scanner hardware and improved methodology. Sodium MRI is being evaluated for stroke and tumor detection, for breast cancer studies, and for the assessment of osteoarthritis and muscle and kidney functions, to name just a few. In this article, we aim to present an up-to-date review of the theoretical background, the methodology, the challenges and limitations, and current and potential new applications of sodium MRI.

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Section: Theoretical Formalism and Pulse Sequencesmentioning

confidence: 99%

“…In order to follow the sequence of events in experiments at high magnetic fields, one can follow these simple rules: [3,48]. …”

Section: Theoretical Formalism and Pulse Sequencesmentioning

confidence: 99%

See 1 more Smart Citation

Sodium MRI: Methods and applications

Madelin

Lee

Regatte

et al. 2014

Progress in Nuclear Magnetic Resonance Spectroscopy

Self Cite

190

209

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“…In this limit the secular approximation to the first order quadrupolar interaction is appropriate and is given by [19] [20]…”

Section: Simulationmentioning

confidence: 99%

Simulation studies of instrumental artifacts on spin I=1 double quantum filtered NMR spectroscopy

Sun

Boutis

2010

Journal of Magnetic Resonance

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We report on the results of a simulation based study of the effect of various experimental artifacts for spin I=1 double quantum filtered NMR. The simulation captures the effects of static field inhomogeneity, finite pulse widths, phase errors, transients and radio frequency inhomogeneity. We simulated the spectral distortions introduced under these errors for four, eight and sixteen step phase cycles that are well known in the NMR community. The dominating pulse errors are radio frequency field inhomogeneity and antisymmetric pulse transients. These errors result in the reduction of signal intensity as well as an introduction of distortions in the detected double quantum filtered spectrum. Using the simulation tool we studied the improvement one obtains when implementing a sixteen step phase cycle over a four step phase cycle. The results indicate that implementing a sixteen step phase cycle over an eight or four step phase cycle does not result in a significant reduction in the DQF intensity loss, or reduction in spectral distortions for antisymmetric transients.

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“…The Euler angles α, β, γ, relate the principal axis frame to the laboratory frame. With these conventions, rQCC represents the splitting in Hz between the resonance transitions under the action of the quadrupolar coupling (18).…”

Section: Theorymentioning

confidence: 99%

Behavior of ordered sodium in enzymatically depleted cartilage tissue

Wen

Regatte

Schweitzer

et al. 2006

Magnetic Resonance in Med

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The onset of cartilage tissue disorders can be characterized by a loss of proteoglycans (PGs) and diagnosed by contrast-enhanced proton ( 1 H) MRI techniques, as well as sodium MRI. The behavior of sodium located in anisotropic environments, is examined as a function of cartilage degeneration. PGs are proteolytically depleted from the cartilage samples, which gives rise to a decrease of the ordered sodium content. More surprisingly, however, the residual quadrupolar couplings are shown to increase with increasing depletion levels. Since the residual quadrupolar couplings are intimately related to local order and anisotropic motion, measuring their distribution in cartilage may provide insight into the structural changes that occur within the tissue upon degradation. In this study relatively mild orientational dependence of the couplings was found. Little or no free sodium was observed in the cartilage specimens under study. Articular cartilage is a dense connective tissue composed primarily of water, collagen fiber bundles, and proteoglycan (PG) aggregates. Cartilage functions as the load-bearing surface in the joints of the musculoskeletal system. Modern developments in chondroprotective therapies, gene therapy, cartilage grafting, and tissue engineering have increased the demand for sensitive, reliable, and noninvasive techniques that can enable the detection of biochemical changes in cartilage in vivo.The major macromolecules in cartilage are collagen type II and PGs. PGs provide much of the compressive stiffness through electrostatic repulsion, and collagen provides tensile and shear strength. Several studies have shown that the early stage of osteoarthritis (OA) is primarily associated with a loss of PGs, with minor changes in collagen structure and content (1-3). PGs consist of a central protein core to which a large number of negatively charged glycosaminoglycan (GAG) side chains are covalently attached. The GAG molecules consist of long-chain unbranched repeating dimeric polysaccharides, the most common of these being chondroitin-4-sulfate, chondroitin-6-sulfate, and keratan sulfate. Their negatively-charged side groups (sulfates and carboxylates) draw sodium ions into the framework to maintain overall electroneutrality. The swelling pressure generated by sodium ions allows cartilage to maintain its form and durability.Conventional proton ( 1 H) MRI techniques, such as T 1 , T 2 , and magnetization transfer (MT)-weighted imaging, have been shown to be inconclusive in detecting early changes in OA (4 -6). Recent work on delayed gadolinium (Gd)-enhanced MRI of cartilage (dGEMRIC) (7,8) and sodium MRI (9,10) have shown that it is possible to measure PG changes in cartilage both in vivo and in vitro. Although the dGEMRIC method offers certain advantages, it requires the intravenous injection of contrast agent, a significant delay before a T 1 map can be obtained, and joint exercise after the injection of the contrast agent for better penetration of Gd (DTPA) 2-into the cartilage. Also, there is a need for ac...

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From nuclear structure to the quadrupolar NMR interaction and high-resolution spectroscopy

Cited by 131 publications

References 105 publications

Sodium MRI: Methods and applications

Sodium MRI: Methods and applications

Simulation studies of instrumental artifacts on spin I=1 double quantum filtered NMR spectroscopy

Behavior of ordered sodium in enzymatically depleted cartilage tissue

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