Broadband decoupled, <sup>1</sup>H‐localized <sup>13</sup>C MRS of the human brain at 4 tesla

Gruetter, Rolf; Adriany, Gregor; Merkle, Hellmut; Andersen, Peter M.

doi:10.1002/mrm.1910360503

Cited by 76 publications

(79 citation statements)

References 26 publications

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“…Previous studies have reported the successful use of 1 H to 13 C polarization transfer in the human brain (23,24). However, these studies used localization techniques and were thus restricted to small regions.…”

Section: Fig 8 Natural Abundance In Vivomentioning

confidence: 99%

Sensitivity‐enhanced ¹³C MR spectroscopy of the human brain at 3 Tesla

Klomp

Renema

Graaf

et al. 2005

Magnetic Resonance in Med

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A new coil design for sensitivity-enhanced 13 C MR spectroscopy (MRS) of the human brain is presented. The design includes a quadrature transmit/receive head coil optimized for 13 C MR sensitivity. Loss-less blocking circuits inside the coil conductors allow this coil to be used inside a homogeneous circularly polarized 1 H B 1 field for 1 H decoupled 13 C MRS. A quadrature 1 H birdcage coil optimized for minimal local RF heating makes broadband 1 H decoupling in the entire human brain possible at 3 Tesla while remaining well within international safety guidelines for RF absorption. Apart from a substantial increase in sensitivity compared to conventional small linear coils, the quadrature 13 C coil combined with the quadrature 1 H birdcage coil allows efficient cross polarization (CP) in the brain, resulting in an additional 3.5-fold sensitivity improvement compared to direct 13 C measurements without nuclear Overhauser enhancement (NOE) or polarization transfer. Combined with the gain in power efficiency, this setup allows broadband 1 H to 13 C CP over large areas of the brain.

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Section: Fig 8 Natural Abundance In Vivomentioning

confidence: 99%

Sensitivity‐enhanced ¹³C MR spectroscopy of the human brain at 3 Tesla

Klomp

Renema

Graaf

et al. 2005

Magnetic Resonance in Med

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“…In contrast, direct detection requires 1 H decoupling, i.e., high-frequency but narrowband decoupling (⌬ / ϳ 2 ppm). Both direct and indirect approaches are confronted to specific absorption rates approaching the FDA guidelines, even when quadrature half-volume coils are used for decoupling (8,11,25,30), as discussed by Adriany and Gruetter (11). In this regard, it is advantageous to perform indirect detection without decoupling using a 1 H PRESS sequence.…”

Section: Nmr Detection Of 13 C Label On Human Systemsmentioning

confidence: 99%

NMR measurement of brain oxidative metabolism in monkeys using ¹³C‐labeled glucose without a ¹³C radiofrequency channel

Boumezbeur

Besret

Valette

et al. 2004

Magnetic Resonance in Med

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13 C-bonded protons of glutamate. To take full advantage of the simultaneous detection of 12 C-and 13 Cbonded protons, we implemented a quantitation procedure to properly measure both glutamate C4 and C3 enrichments. This procedure relies on LCModel analysis with a basis set to account for simultaneous signal changes of protons bound to 12 C and 13 C. Signal changes were mainly attributed to 12 C-and 13 C-bonded protons of glutamate. As a result, we were able to measure the tricarboxylic acid (TCA) cycle flux in a 3.9 cm 3 voxel centered in the monkey brain on a whole-body 3 Tesla system (V TCA ‫؍‬ 0.55 ؎ 0.04 mol.g ؊1 .min ؊1 , N ‫؍‬ 4). This work demonstrates that oxidative metabolism can be quantified in deep structures of the brain on clinical MRI systems, without the need for a 13 NMR studies of metabolism with the use of 13 C-labeled glucose have considerably evolved over the past 25 years, following pioneer work on cell suspensions (1,2). Since the sensitivity of 13 C spectroscopy is intrinsically low, investigators performed the first in vivo brain studies using indirect { 13 C}-1 H detection of amino-acid labeling, to take advantage of the higher sensitivity of 1 H (3,4). Because of the overwhelming signal of 12 C-bonded protons, and the strong peak overlapping on 1 H spectra, 13 C-coupled protons of glutamate (Glu) have been detected with the use of such editing techniques as POCE (3). This approach has been implemented successfully in several research units, leading to in vivo localized measurements of brain metabolic fluxes, such as the TCA cycle flux V TCA (5-10). However, heteronuclear editing techniques require the use of both 1 H and 13 C radiofrequency (RF) transmitters and coils, as well as appropriate pulse sequences that are not implemented on most clinical MR systems. RF decoupling associated with heteronuclear editing is also problematic in human studies, due to power deposition to the tissue (11). Moreover, POCE-like sequences only detect the increase in 13 C-coupled protons during the course of 13 C enrichment. They ignore the corresponding decrease in 12 C-bonded protons, and thus miss half of the available information. Since the mid 1980s, when the early POCE measurements were obtained, hardware improvements have led to higher spectrum quality and stability; thus, the requirement for editing techniques is now questionable.In this context, our first objective was to demonstrate that 13 C incorporation into glutamate inside deep structures of the monkey brain could be detected with the sensitivity of 1 H without editing, using a 1 H point-resolved spectroscopy (PRESS) sequence on a whole-body 3 Tesla system. Our second objective was to propose a 13 C quantitation procedure based on LCModel analysis (12), which takes full advantage of the simultaneous detection of the decrease in 12 C-bonded protons of glutamate and the increase in 13 C-coupled satellites. V TCA was assessed after it was converted into glutamate 13 C4 and 13 C3 fractional enrichments (FEs). The results demonstrate that on...

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“…In principle, two strategies are available: isotope or magnetic labeling. Pulse chase or isotope labeling experiments 2,36 are beyond the scope of this review article, only spin labeling or spin transfer experiments will be covered. 10,37 Creatine kinase reaction…”

Section: In Vivo Applicationsmentioning

confidence: 99%

Magnetization transfer MRS

Leibfritz¹,

Dreher²

2001

NMR in Biomedicine

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This review deals with magnetization transfer (MT) effects observed in in vivo NMR spectroscopy. The basic experimental methods of MT experiments, the underlying kinetic mechanisms as well as the evaluation of measured data by fits to two-or three-pool models are described. Experimental results of both 31 P and 1 H in vivo MRS are reviewed showing the potential of MT experiments to characterize kinetic equilibrium reactions. This includes reactions where all involved components are MR visible, as well as situations where one indirectly measures pools of bound spins which cannot directly be observed in vivo. In particular, MT effects are described which have been observed in in vivo 1 H NMR spectra measured on the animal or human brain or on skeletal muscle. Possible mechanisms for the strong MT effects observed for the signals of creatine/phosphocreatine, lactate, alcohol and other metabolites are discussed. It is also emphasized that MT effects caused by water suppression techniques may lead to systematic errors in the quantification of in vivo 1 H NMR spectra.

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Broadband decoupled, ¹H‐localized ¹³C MRS of the human brain at 4 tesla

Cited by 76 publications

References 26 publications

Sensitivity‐enhanced ¹³C MR spectroscopy of the human brain at 3 Tesla

Sensitivity‐enhanced ¹³C MR spectroscopy of the human brain at 3 Tesla

NMR measurement of brain oxidative metabolism in monkeys using ¹³C‐labeled glucose without a ¹³C radiofrequency channel

Magnetization transfer MRS

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Broadband decoupled, 1H‐localized 13C MRS of the human brain at 4 tesla

Cited by 76 publications

References 26 publications

Sensitivity‐enhanced 13C MR spectroscopy of the human brain at 3 Tesla

Sensitivity‐enhanced 13C MR spectroscopy of the human brain at 3 Tesla

NMR measurement of brain oxidative metabolism in monkeys using 13C‐labeled glucose without a 13C radiofrequency channel

Magnetization transfer MRS

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Broadband decoupled, ¹H‐localized ¹³C MRS of the human brain at 4 tesla

Sensitivity‐enhanced ¹³C MR spectroscopy of the human brain at 3 Tesla

Sensitivity‐enhanced ¹³C MR spectroscopy of the human brain at 3 Tesla

NMR measurement of brain oxidative metabolism in monkeys using ¹³C‐labeled glucose without a ¹³C radiofrequency channel