High-resolution NMR spectroscopy in inhomogeneous fields

Chen, Zhong; Cai, Shuhui; Huang, Yuqing; Lin, Yulan

doi:10.1016/j.pnmrs.2015.05.003

Cited by 31 publications

(22 citation statements)

References 147 publications

(182 reference statements)

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“…Over the years, significant efforts have been made to overcome these magnetic susceptibility distortions. Within the past two decades, an interesting approach, first introduced by Warren et al and then further developed by Chen et al correlates the chemicals shifts of water to solutes over distances greater than local magnetic susceptibility distortions in a 2D experiment. Recently, a phase sensitive version of the approach, namely, in‐phase intermolecular single‐quantum coherence (IP‐iSQC), was developed specifically for living organisms …”

Section: Nmr Experiments For In Vivo Flow Nmrmentioning

confidence: 99%

“…The first reported in vivo NMR studies were likely from Waller et al in which 31 P NMR was used to investigate Chironomus tentans larvae and Daphnia magna . This technique was then further developed and refined to study other aquatic organisms . For example, 1D 31 P NMR was extensively used to investigate the physiology of Balanus nubilis , Clarias batrachus embryo, and larvae of plaice under in vivo conditions, where various important energy molecules, such as ATP or ADP, were identified based on their unique 31 P chemical shifts signatures .…”

Section: Introductionmentioning

confidence: 99%

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Flow‐based in vivo NMR spectroscopy of small aquatic organisms

Soong

Mobarhan

Tabatabaei

et al. 2019

Magnetic Reson in Chemistry

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NMR applied to living organisms is arguably the ultimate tool for understanding environmental stress responses and can provide desperately needed information on toxic mechanisms, synergistic effects, sublethal impacts, recovery, and biotransformation of xenobiotics. To perform in vivo NMR spectroscopy, a flow cell system is required to deliver oxygen and food to the organisms while maintaining optimal line shape for NMR spectroscopy. In this tutorial, two such flow cell systems and their constructions are discussed: (a) a single pump high‐volume flow cell design is simple to build and ideal for organisms that do not require feeding (i.e., eggs) and (b) a more advanced low‐volume double pump flow cell design that permits feeding, maintains optimal water height for water suppression, improves locking and shimming, and uses only a small recirculating volume, thus reducing the amount of xenobiotic required for testing. In addition, key experimental aspects including isotopic enrichment, water suppression, and 2D experiments for both 13C enriched and natural abundance organisms are discussed.

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Section: Nmr Experiments For In Vivo Flow Nmrmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Flow‐based in vivo NMR spectroscopy of small aquatic organisms

Soong

Mobarhan

Tabatabaei

et al. 2019

Magnetic Reson in Chemistry

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“…In particular, static field inhomogeneity is a long‐standing issue from the early days of nuclear MR (NMR) imaging, which is more pronounced at UHF. Challenges originating from B 0 inhomogeneities are anticipated and reported in literature, including geometric distortion, spectra line broadening and weak water suppression, shortening

T_{2}^{*}

relaxation time, or voiding the signal . There are a few postprocessing approaches which can partially correct the consequences of poor B 0 uniformity .…”

Section: Introductionmentioning

confidence: 99%

A 32‐channel multi‐coil setup optimized for human brain shimming at 9.4T

Aghaeifar

Zhou

Heule

et al. 2019

Magnetic Resonance in Med

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Purpose: A multi-coil shim setup is designed and optimized for human brain shimming. Here, the size and position of a set of square coils are optimized to improve the shim performance without increasing the number of local coils. Utilizing such a setup is especially beneficial at ultrahigh fields where B 0 inhomogeneity in the human brain is more severe. Methods: The optimization started with a symmetric arrangement of 32 independent coils. Three parameters per coil were optimized in parallel, including angular and axial positions on a cylinder surface and size of the coil, which were constrained by cylinder size, construction consideration, and amplifiers specifications. B 0 maps were acquired at 9.4T in 8 healthy volunteers for use as training data. The global and dynamic shimming performance of the optimized multi-coil were compared in simulations and measurements to a symmetric design and to the scanner's second-order shim setup, respectively. Results: The optimized multi-coil performs better by 14.7% based on standard deviation (SD) improvement with constrained global shimming in comparison to the symmetric positioning of the coils. Global shimming performance was comparable with a symmetric 65-channel multi-coil and full fifth-order spherical harmonic shim coils. On average, an SD of 48.4 and 31.9 Hz was achieved for in vivo measurements after global and dynamic slice-wise shimming, respectively. Conclusions: An optimized multi-coil shim setup was designed and constructed for human whole-brain shimming. Similar performance of the multi-coils with many channels can be achieved with a fewer number of channels when the coils are optimally arranged around the target. K E Y W O R D SB 0 inhomogeneity, B 0 shimming, echo planar imaging, multi-coil, optimization, ultrahigh field 750 |

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“…First, according to the iZQC mechanism, a concentrated solvent component with a single resonance should be contained in investigation samples and desired components are dissolved as solutes into the solvent. 44 It is relatively easy to meet this requirement in practical applications since most chemical solution and biological samples usually contain such a solvent. However, this requirement may be limited in some measurements in which the solvent is not contained, such as oil samples.…”

Section: Analytical Chemistrymentioning

confidence: 99%

Ultrahigh-Resolution NMR Spectroscopy for Rapid Chemical and Biological Applications in Inhomogeneous Magnetic Fields

et al. 2017

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NMR spectroscopy is a commonly used analytical technique in practical applications, and its applicability is further promoted by pure chemical shift techniques based on spectral simplification for analyses. Unfortunately, magnetic field inhomogeneity caused by adverse experimental conditions remains an obstacle restricting NMR applications. In this study, we introduce a new NMR method for high-resolution pure shift proton (H) NMR measurements in inhomogeneous magnetic fields. We demonstrate that the method allows one to perform chemical analyses on complex solutions in deshimmed magnetic fields, to obtain metabolite information on intact biological tissues with intrinsic field inhomogeneities and to achieve in situ electrochemical detection under externally adverse field conditions. This approach is readily implemented on common commercial NMR instruments without field shimming and locking procedures, specialized hardware requirements as well as complicated sample pretreatments. It provides an effective tool for NMR applications to high-resolution chemical and biological measurements under inhomogeneous magnetic field conditions.

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High-resolution NMR spectroscopy in inhomogeneous fields

Cited by 31 publications

References 147 publications

Flow‐based in vivo NMR spectroscopy of small aquatic organisms

Flow‐based in vivo NMR spectroscopy of small aquatic organisms

A 32‐channel multi‐coil setup optimized for human brain shimming at 9.4T

Ultrahigh-Resolution NMR Spectroscopy for Rapid Chemical and Biological Applications in Inhomogeneous Magnetic Fields

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