Sensitivity‐enhanced <sup>13</sup>C MR spectroscopy of the human brain at 3 Tesla

Klomp, Dennis W. J.; Renema, W. Klaas Jan; Graaf, Marinette van der; Galan, Bastiaan E. de; Kentgens, A.P.M.; Heerschap, Arend

doi:10.1002/mrm.20745

Cited by 49 publications

(40 citation statements)

References 22 publications

(68 reference statements)

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“…The bandwidth of 1 H ISIS was 6.5 kHz, leading to a chemical shift error of Ϯ 5% in all three directions. A homogeneous 1 H transmit birdcage coil for maximal field homogeneity in the mouse brain was used for optimal 90°and 180°RF pulses in the 1 H part of the DEPT sequence even with hard pulses (15). This homogeneous 1 H coil also made spoil gradients less crucial for eliminating unwanted, offset-dependent amplitude oscillations.…”

Section: In Vivo 13 C Mr Spectroscopymentioning

confidence: 99%

Localized sensitivity enhanced in vivo ¹³C MRS to detect glucose metabolism in the mouse brain

Nabuurs

Klomp

Veltien

et al. 2008

Magnetic Resonance in Med

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The application of in vivo 13 C MR spectroscopy to mouse brain models is potentially valuable for improving the understanding of cerebral carbohydrate metabolism and glutamatergic neurotransmission in various neuropathologies. However, the low sensitivity of 13 C nuclei and contaminating signals of lipids in the relatively small mouse brain make this application rather challenging. To meet these technical challenges, localized semi-adiabatic distortionless enhanced polarization transfer (DEPT) MR spectroscopy in combination with a continuous intravenous [1,6-13 C 2 ] glucose infusion was implemented to detect glucose metabolism in isoflurane-anesthetized mice at 7T. The signal enhancement and high spectral resolution obtained in these experiments enabled the separate determination of 13 Energy metabolism in the brain and other organs has been frequently studied by in vivo 13 C MR spectroscopy (MRS). With this method the conversion of 13 C labeled compounds in metabolic pathways can be monitored after the infusion of 13 C labeled substrates such as glucose. From this dynamic information the quantitative determination of substrate uptake and metabolic fluxes is possible with the help of metabolic models (1-4).Most in vivo 13 C MRS experiments on brain have been performed on relatively large volumes in humans and animals like primates or rats. Detailed in vivo 13 C MRS studies of pathologies in humans may be cumbersome for various reasons such as high cost and demand on patient compliance. The application of dynamic in vivo 13 C MRS to murine transgenic models, especially for transporter deficiencies, mitochondrial dysfunction and energy-related modifications in brain would provide excellent opportunities to study metabolism in brain pathologies. However, until now 13 C MRS of mouse brain has mainly been limited to experiments on tissue extracts (5). The first in vivo 13 C MRS of transgenic mouse brain used surface coil localization to determine glucose clearance after a [1-13 C] glucose bolus (6). The contamination of signals from naturally abundant 13 C in lipids, originating from subcutaneous fat tissue, hampered the detection of other compounds such as glutamate (Glu) and glutamine (Gln) in this study. Recently, we demonstrated the elimination of lipid signals by subtraction methods to monitor the time courses of label incorporation in Glu and Gln C4 and C3 in mouse brain at 7T (7). These studies were performed after a bolus injection of 13 C labeled glucose, whereas fluxes are commonly calculated using a glucose infusion protocol that aims at achieving a step function in the 13 C isotopic enrichment of plasma glucose.In vivo 13 C MRS of the small mouse brain is especially challenged by a relatively low sensitivity. In the past several methods were introduced to increase sensitivity of in vivo 13 C MRS. A first approach is infusing double-labeled [1,6-13 C 2 ] instead of single-labeled [1-13 C] glucose, yielding a twofold signal increase for carbons in metabolites downstream of fructose 1,6-biphosphate (8). Se...

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Section: In Vivo 13 C Mr Spectroscopymentioning

confidence: 99%

Localized sensitivity enhanced in vivo ¹³C MRS to detect glucose metabolism in the mouse brain

Nabuurs

Klomp

Veltien

et al. 2008

Magnetic Resonance in Med

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“…two physicallydecoupled overlapped 1 H loops) have been widely used both in animal [18,29,57,58,78,80,81] and human studies [21,76,77,82]. Relative to the linear coil design, an overlapped quadrature coil enhances sensitivity by a factor of √2 [79,83], and 13 C-quadrature coils have been designed in combination with either a 1 H-volume coil [84] or a 1 H-quadrature coil [85]. Indeed, an SNR enhancement of nearly √2 has been achieved to detect glycogen 13 C-1 in vivo at 7 T with the latter design when comparing to the linear-13 C/ quadrature-1 H coil [85].…”

Section: Radio-frequency (Rf) Coil Designmentioning

confidence: 99%

Technical and experimental features of Magnetic Resonance Spectroscopy of brain glycogen metabolism

Soares

Gruetter

Lei

2017

Analytical Biochemistry

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a b s t r a c tIn the brain, glycogen is a source of glucose not only in emergency situations but also during normal brain activity. Altered brain glycogen metabolism is associated with energetic dysregulation in pathological conditions, such as diabetes or epilepsy. Both in humans and animals, brain glycogen levels have been assessed non-invasively by Carbon-13 Magnetic Resonance Spectroscopy ( 13 C-MRS) in vivo. With this approach, glycogen synthesis and degradation may be followed in real time, thereby providing valuable insights into brain glycogen dynamics. However, compared to the liver and muscle, where glycogen is abundant, the sensitivity for detection of brain glycogen by 13 C-MRS is inherently low. In this review we focus on strategies used to optimize the sensitivity for 13 C-MRS detection of glycogen. Namely, we explore several technical perspectives, such as magnetic field strength, field homogeneity, coil design, decoupling, and localization methods. Furthermore, we also address basic principles underlying the use of 13 C-labeled precursors to enhance the detectable glycogen signal, emphasizing specific experimental aspects relevant for obtaining kinetic information on brain glycogen.

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“…Both coils were double- P resonance frequencies using inductive traps as described previously (10), and parallel trap circuits with PIN diodes were added to enable active detuning during 1 H signal reception. This method has proven to exhibit very little loss compared with singletuned coil when assuming low-loaded Q values and low inductances in the traps (17). An alternative approach would be to avoid the use of small inductors using the method described by Schnall et al (18).…”

Section: Hardwarementioning

confidence: 99%

Radiofrequency configuration to facilitate bilateral breast³¹P MR spectroscopic imaging and high-resolution MRI at 7 Tesla

Velden

Italiaander²,

Kemp

et al. 2014

Magn. Reson. Med.

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Purpose: High-resolution MRI combined with phospholipid detection may improve breast cancer grading. Currently, configurations are optimized for either high-resolution imaging or 31 P spectroscopy. To be able to perform both imaging as well as spectroscopy in a single session, we integrated a 1 H receiver array into a 1 H-31 P transceiver at 7T. To ensure negligible signal loss due to coupling between elements, we investigated the use of a floating decoupling loop to enable bilateral MRI and 31 P MRS. Methods: Two quadrature double-tuned radiofrequency coils were designed for bilateral breast MR with active detuning at the 1 H frequency. The two coils were placed adjacent to each other and decoupled for both frequencies with a single resonant floating loop. Sensitivity of the bilateral configuration, facilitating space for a 26-element 1 H receive array, was compared with a transceiver configuration. Results: The floating loop was able to decouple the elements over 20 dB for both frequencies. Enlargement of the elements, to provide space for the receivers, and the addition of detuning electronics altered the 31 P sensitivity by 0.4 dB. Conclusion: Dynamic contrast-enhanced scans of 0.7 mm isotropic, diffusion-weighted imaging, and 31 P MR spectroscopic imaging can be acquired at 7T in a single session as demonstrated in a patient with invasive ductal carcinoma. Magn

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

Cited by 49 publications

References 22 publications

Localized sensitivity enhanced in vivo ¹³C MRS to detect glucose metabolism in the mouse brain

Localized sensitivity enhanced in vivo ¹³C MRS to detect glucose metabolism in the mouse brain

Technical and experimental features of Magnetic Resonance Spectroscopy of brain glycogen metabolism

Radiofrequency configuration to facilitate bilateral breast³¹P MR spectroscopic imaging and high-resolution MRI at 7 Tesla

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

Cited by 49 publications

References 22 publications

Localized sensitivity enhanced in vivo 13C MRS to detect glucose metabolism in the mouse brain

Localized sensitivity enhanced in vivo 13C MRS to detect glucose metabolism in the mouse brain

Technical and experimental features of Magnetic Resonance Spectroscopy of brain glycogen metabolism

Radiofrequency configuration to facilitate bilateral breast31P MR spectroscopic imaging and high-resolution MRI at 7 Tesla

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

Localized sensitivity enhanced in vivo ¹³C MRS to detect glucose metabolism in the mouse brain

Localized sensitivity enhanced in vivo ¹³C MRS to detect glucose metabolism in the mouse brain

Radiofrequency configuration to facilitate bilateral breast³¹P MR spectroscopic imaging and high-resolution MRI at 7 Tesla