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Lysak DH, Bermel W, Moxley-Paquette V, Michal C, Ghosh-Biswas R, Soong R, Nashman B, Lacerda A, Simpson AJ. Cutting without a Knife: A Slice-Selective 2D 1H- 13C HSQC NMR Sequence for the Analysis of Inhomogeneous Samples. Anal Chem 2023; 95:14392-14401. [PMID: 37713676 DOI: 10.1021/acs.analchem.3c02756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/17/2023]
Abstract
Nuclear magnetic resonance (NMR) is a powerful technique with applications ranging from small molecule structure elucidation to metabolomics studies of living organisms. Typically, solution-state NMR requires a homogeneous liquid, and the whole sample is analyzed as a single entity. While adequate for homogeneous samples, such an approach is limited if the composition varies as would be the case in samples that are naturally heterogeneous or layered. In complex samples such as living organisms, magnetic susceptibility distortions lead to broad 1H line shapes, and thus, the additional spectral dispersion afforded by 2D heteronuclear experiments is often required for metabolite discrimination. Here, a novel, slice-selective 2D, 1H-13C heteronuclear single quantum coherence (HSQC) sequence was developed that exclusively employs shaped pulses such that only spins in the desired volume are perturbed. In turn, this permits multiple volumes in the tube to be studied during a single relaxation delay, increasing sensitivity and throughput. The approach is first demonstrated on standards and then used to isolate specific sample/sensor elements from a microcoil array and finally study slices within a living earthworm, allowing metabolite changes to be discerned with feeding. Overall, slice-selective NMR is demonstrated to have significant potential for the study of layered and other inhomogeneous samples of varying complexity. In particular, its ability to select subelements is an important step toward developing microcoil receive-only arrays to study environmental toxicity in tiny eggs, cells, and neonates, whereas localization in larger living species could help better correlate toxin-induced biochemical responses to the physical localities or organs involved.
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Affiliation(s)
- Daniel H Lysak
- Environmental NMR Center, Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - Wolfgang Bermel
- Bruker BioSpin GmbH, Rudolf-Plank-Str. 23, 76275 Ettlingen, Germany
| | - Vincent Moxley-Paquette
- Environmental NMR Center, Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - Carl Michal
- Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
| | - Rajshree Ghosh-Biswas
- Environmental NMR Center, Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - Ronald Soong
- Environmental NMR Center, Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - Ben Nashman
- Synex Medical, 2 Bloor Street E, Suite 310, Toronto, ON M4W 1A8,Canada
| | - Andressa Lacerda
- Synex Medical, 2 Bloor Street E, Suite 310, Toronto, ON M4W 1A8,Canada
| | - Andre J Simpson
- Environmental NMR Center, Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
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Barekatain Y, Yan VC, Arthur K, Ackroyd JJ, Khadka S, De Groot J, Huse JT, Muller FL. Robust detection of oncometabolic aberrations by 1H- 13C heteronuclear single quantum correlation in intact biological specimens. Commun Biol 2020; 3:328. [PMID: 32587392 PMCID: PMC7316726 DOI: 10.1038/s42003-020-1055-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 05/29/2020] [Indexed: 01/02/2023] Open
Abstract
Magnetic resonance (MR) spectroscopy has potential to non-invasively detect metabolites of diagnostic significance for precision oncology. Yet, many metabolites have similar chemical shifts, yielding highly convoluted 1H spectra of intact biological material and limiting diagnostic utility. Here, we show that hydrogen–carbon heteronuclear single quantum correlation (1H–13C HSQC) offers dramatic improvements in sensitivity compared to one-dimensional (1D) 13C NMR and significant signal deconvolution compared to 1D 1H spectra in intact biological settings. Using a standard NMR spectroscope with a cryoprobe but without specialized signal enhancing features such as magic angle spinning, metabolite extractions or 13C-isotopic enrichment, we obtain well-resolved 2D 1H–13C HSQC spectra in live cancer cells, in ex vivo freshly dissected xenografted tumors and resected primary tumors. This method can identify tumors with specific oncometabolite alterations such as IDH mutations by 2-hydroxyglutarate and PGD-deleted tumors by gluconate. Results suggest potential of 1H–13C HSQC as a non-invasive diagnostic in precision oncology. Barekatain et al. demonstrate that hydrogen–carbon heteronuclear single quantum correlation (HSQC) spectra, obtained using a standard NMR spectroscope, can detect tumours with specific oncometabolite alterations including IDH1 mutant glioblastoma, suggesting the feasibility of this method as a diagnostic tool.
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Affiliation(s)
- Yasaman Barekatain
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Victoria C Yan
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Kenisha Arthur
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Jeffrey J Ackroyd
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - Sunada Khadka
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA
| | - John De Groot
- Department of Neuro-Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Jason T Huse
- Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Florian L Muller
- Department of Cancer Systems Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, 77054, USA.
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Chen H, De Feyter HM, Brown PB, Rothman DL, Cai S, de Graaf RA. Comparison of direct 13C and indirect 1H-[ 13C] MR detection methods for the study of dynamic metabolic turnover in the human brain. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 283:33-44. [PMID: 28869920 DOI: 10.1016/j.jmr.2017.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 08/02/2017] [Accepted: 08/10/2017] [Indexed: 06/07/2023]
Abstract
A wide range of direct 13C and indirect 1H-[13C] MR detection methods exist to probe dynamic metabolic pathways in the human brain. Choosing an optimal detection method is difficult as sequence-specific features regarding spatial localization, broadband decoupling, spectral resolution, power requirements and sensitivity complicate a straightforward comparison. Here we combine density matrix simulations with experimentally determined values for intrinsic 1H and 13C sensitivity, T1 and T2 relaxation and transmit efficiency to allow selection of an optimal 13C MR detection method for a given application and magnetic field. The indirect proton-observed, carbon-edited (POCE) detection method provides the highest accuracy at reasonable RF power deposition both at 4T and 7T. The various polarization transfer methods all have comparable performances, but may become infeasible at 7T due to the high RF power deposition. 2D MR methods have limited value for the metabolites considered (primarily glutamate, glutamine and γ-amino butyric acid (GABA)), but may prove valuable when additional information can be extracted, such as isotopomers or lipid composition. While providing the lowest accuracy, the detection of non-protonated carbons is the simplest to implement with the lowest RF power deposition. The magnetic field homogeneity is one of the most important parameters affecting the detection accuracy for all metabolites and all acquisition methods.
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Affiliation(s)
- Hao Chen
- Magnetic Resonance Research Center, Department of Radiology and Biomedical Imaging, Yale University, School of Medicine, New Haven, CT, USA; Department of Electronic Science, Xiamen University, Xiamen, Fujian, China
| | - Henk M De Feyter
- Magnetic Resonance Research Center, Department of Radiology and Biomedical Imaging, Yale University, School of Medicine, New Haven, CT, USA
| | - Peter B Brown
- Magnetic Resonance Research Center, Department of Radiology and Biomedical Imaging, Yale University, School of Medicine, New Haven, CT, USA
| | - Douglas L Rothman
- Magnetic Resonance Research Center, Department of Radiology and Biomedical Imaging, Yale University, School of Medicine, New Haven, CT, USA
| | - Shuhui Cai
- Department of Electronic Science, Xiamen University, Xiamen, Fujian, China
| | - Robin A de Graaf
- Magnetic Resonance Research Center, Department of Radiology and Biomedical Imaging, Yale University, School of Medicine, New Haven, CT, USA.
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de Graaf RA, De Feyter HM, Rothman DL. High-sensitivity, broadband-decoupled (13) C MR spectroscopy in humans at 7T using two-dimensional heteronuclear single-quantum coherence. Magn Reson Med 2015; 74:903-14. [PMID: 25264872 PMCID: PMC4377311 DOI: 10.1002/mrm.25470] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 08/11/2014] [Accepted: 08/31/2014] [Indexed: 11/09/2022]
Abstract
PURPOSE Carbon-13 ((13) C) magnetic resonance spectroscopy (MRS) has an intrinsically low NMR sensitivity that often leads to large acquisition volumes or long scan times. While the use of higher magnetic fields can overcome the sensitivity limitations, high radiofrequency (RF) power deposition associated with proton-decoupling limits the achievable gain. Two-dimensional (2D) heteronuclear single quantum coherence (HSQC) MRS is a method that uses the high chemical specificity of (13) C MRS while retaining the high sensitivity of (1) H detection. Due to the 2D nature of the method, proton-decoupled (13) C MR spectra can be obtained without the use of high-powered decoupling pulses. METHODS A novel three-dimensional (3D) localized 2D HSQC method based on 3D STEAM localization is presented and implemented at 7T. The low RF power deposition of the method allows TR variation along the indirect dimension which, in combination with controlled aliasing, leads to an acceleration of 11.8 relative to a standard 2D NMR acquisition. RESULTS Artifact-free, high-quality and high-sensitivity 2D HSQC spectra were obtained for all subjects in 19 min from a small (9 mL) volume placed in the leg adipose tissue. Complete proton decoupling was achieved along the indirect (13) C dimension despite the absence of broadband proton-decoupling pulses. The high chemical specificity along the indirect (13) C dimension allowed the detection of 19 unique resonances from which the lipids could be characterized in terms of saturation and omega-6/omega-3 fatty acid ratio. CONCLUSION It has been demonstrated that high-quality 2D HSQC NMR spectra can be acquired from human adipose tissue at 7T. The HSQC method is methodologically simple and robust and is flexible regarding trade-offs between temporal and spectral resolution. 2D HSQC has a strong potential to become a default method in natural-abundance or (13) C-enriched studies of human metabolism in vivo.
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Affiliation(s)
- Robin A de Graaf
- Department of Diagnostic Radiology, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Henk M De Feyter
- Department of Diagnostic Radiology, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Douglas L Rothman
- Department of Diagnostic Radiology, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA
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5
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Doan BT, Autret G, Mispelter J, Méric P, Même W, Montécot-Dubourg C, Corrèze JL, Szeremeta F, Gillet B, Beloeil JC. Simultaneous two-voxel localized (1)H-observed (13)C-edited spectroscopy for in vivo MRS on rat brain at 9.4T: Application to the investigation of excitotoxic lesions. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 198:94-104. [PMID: 19289293 DOI: 10.1016/j.jmr.2009.01.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 01/21/2009] [Accepted: 01/21/2009] [Indexed: 05/27/2023]
Abstract
(13)C spectroscopy combined with the injection of (13)C-labeled substrates is a powerful method for the study of brain metabolism in vivo. Since highly localized measurements are required in a heterogeneous organ such as the brain, it is of interest to augment the sensitivity of (13)C spectroscopy by proton acquisition. Furthermore, as focal cerebral lesions are often encountered in animal models of disorders in which the two brain hemispheres are compared, we wished to develop a bi-voxel localized sequence for the simultaneous bilateral investigation of rat brain metabolism, with no need for external additional references. Two sequences were developed at 9.4T: a bi-voxel (1)H-((13)C) STEAM-POCE (Proton Observed Carbon Edited) sequence and a bi-voxel (1)H-((13)C) PRESS-POCE adiabatically decoupled sequence with Hadamard encoding. Hadamard encoding allows both voxels to be recorded simultaneously, with the same acquisition time as that required for a single voxel. The method was validated in a biological investigation into the neuronal damage and the effect on the Tri Carboxylic Acid cycle in localized excitotoxic lesions. Following an excitotoxic quinolinate-induced localized lesion in the rat cortex and the infusion of U-(13)C glucose, two (1)H-((13)C) spectra of distinct (4x4x4mm(3)) voxels, one centred on the injured hemisphere and the other on the contralateral hemisphere, were recorded simultaneously. Two (1)H bi-voxel spectra were also recorded and showed a significant decrease in N-acetyl aspartate, and an accumulation of lactate in the ipsilateral hemisphere. The (1)H-((13)C) spectra could be recorded dynamically as a function of time, and showed a fall in the glutamate/glutamine ratio and the presence of a stable glutamine pool, with a permanent increase of lactate in the ipsilateral hemisphere. This bi-voxel (1)H-((13)C) method can be used to investigate simultaneously both brain hemispheres, and to perform dynamic studies. We report here the neuronal damage and the effect on the Tri Carboxylic Acid cycle in localized excitotoxic lesions.
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Affiliation(s)
- Bich-Thuy Doan
- Laboratoire de RMN biologique, ICSN-CNRS, UPR, 2301, Avenue de la Terrasse, 91198 Gif sur Yvette cedex, France.
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6
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Xin L, Frenkel H, Mlynárik V, Morgenthaler FD, Gruetter R. Selective resonance suppression1H-[13C] NMR spectroscopy with asymmetric adiabatic RF pulses. Magn Reson Med 2009; 61:260-6. [DOI: 10.1002/mrm.21829] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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7
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Kanamatsu T, Otsuki T, Tokuno H, Nambu A, Takada M, Okamoto K, Watanabe H, Umeda M, Tsukada Y. Changes in the rates of the tricarboxylic acid (TCA) cycle and glutamine synthesis in the monkey brain with hemiparkinsonism induced by intracarotid infusion of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP): Studies by non-invasive 13C-magnetic resonance spectroscopy. Brain Res 2007; 1181:142-8. [DOI: 10.1016/j.brainres.2007.08.051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Revised: 08/21/2007] [Accepted: 08/25/2007] [Indexed: 11/16/2022]
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8
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Xu S, Shen J. In vivo dynamic turnover of cerebral 13C isotopomers from [U-13C]glucose. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 182:221-8. [PMID: 16859940 DOI: 10.1016/j.jmr.2006.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2006] [Revised: 06/27/2006] [Accepted: 07/02/2006] [Indexed: 05/11/2023]
Abstract
An INEPT-based (13)C MRS method and a cost-effective and widely available 11.7 Tesla 89-mm bore vertical magnet were used to detect dynamic (13)C isotopomer turnover from intravenously infused [U-(13)C]glucose in a 211 microL voxel located in the adult rat brain. The INEPT-based (1)H-->(13)C polarization transfer method is mostly adiabatic and therefore minimizes signal loss due to B(1) inhomogeneity of the surface coils used. High quality and reproducible data were acquired as a result of combined use of outer volume suppression, ISIS, and the single-shot three-dimensional localization scheme built in the INEPT pulse sequence. Isotopomer patterns of both glutamate C4 at 34.00 ppm and glutamine C4 at 31.38 ppm are dominated first by a doublet originated from labeling at C4 and C5 but not at C3 (with (1)J(C4C5) = 51 Hz) and then by a quartet originated from labeling at C3, C4, and C5 (with (1)J(C3C4) = 35 Hz). A lag in the transition of glutamine C4 pattern from doublet-dominance to quartet dominance as compared to glutamate C4 was observed, which provides an independent verification of the precursor-product relationship between neuronal glutamate and glial glutamine and a significant intercompartmental cerebral glutamate-glutamine cycle between neurons and glial cells.
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Affiliation(s)
- Su Xu
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD 20892, USA
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9
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Henry PG, Marjanska M, Walls JD, Valette J, Gruetter R, Ugurbil K. Proton-observed carbon-edited NMR spectroscopy in strongly coupled second-order spin systems. Magn Reson Med 2006; 55:250-7. [PMID: 16402370 DOI: 10.1002/mrm.20764] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Proton-observed carbon-edited (POCE) NMR spectroscopy is commonly used to measure 13C labeling with higher sensitivity compared to direct 13C NMR spectroscopy, at the expense of spectral resolution. For weakly coupled first-order spin systems, the multiplet signal at a specific proton chemical shift in POCE spectra directly reflects 13C enrichment of the carbon attached to this proton. The present study demonstrates that this is not necessarily the case for strongly coupled second-order spin systems. In such cases NMR signals can be detected in the POCE spectra even at chemical shifts corresponding to protons bound to 12C. This effect is demonstrated theoretically with density matrix calculations and simulations, and experimentally with measured POCE spectra of [3-13C]glutamate.
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Affiliation(s)
- Pierre-Gilles Henry
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA.
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10
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Yang Y, Chen L, Gao H, Zeng D, Yue Y, Liu M, Lei H, Deng F, Ye C. High-resolution magic-angle spinning (13)C spectroscopy of brain tissue at natural abundance. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2006; 44:263-8. [PMID: 16477685 DOI: 10.1002/mrc.1788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
High-resolution magic-angle spinning (MAS) (1)H and (13)C magnetic resonance spectroscopy (MRS) has recently been applied to study the metabolism in intact biological tissue samples. Because of the low natural abundance and the low gyromagnetic ratio of the (13)C nuclei, signal enhancement techniques such as cross-polarization (CP) and distortionless enhancement by polarization transfer (DEPT) are often employed in MAS (13)C MRS to improve the detection sensitivity. In this study, several sensitivity enhancement techniques commonly used in liquid- and solid-state NMR, including CP, DEPT and nuclear Overhauser enhancement (NOE), were combined with MAS to acquire high-resolution (13)C spectra on intact rat brain tissue at natural abundance, and were compared for their performances. The results showed that different signal enhancement techniques are sensitive to different classes of molecules/metabolites, depending on their molecular weights and mobility. DEPT was found to enhance the signals of low-molecular weight metabolites exclusively, while the signals of lipids, which often are associated with membranes and have relatively lower mobility, were highly sensitive to CP enhancement.
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Affiliation(s)
- Yongxia Yang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071, P. R. China
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11
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Li S, Chen Z, Zhang Y, Lizak M, Bacher J, Innis RB, Shen J. In vivo single-shot, proton-localized 13C MRS of rhesus monkey brain. NMR IN BIOMEDICINE 2005; 18:560-9. [PMID: 16273509 DOI: 10.1002/nbm.993] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A single-shot, proton-localized, polarization transfer (13)C spectroscopic method was proposed and implemented on a 4.7 T scanner for studying rhesus monkey brains. The polarization transfer sequence was mostly adiabatic, minimizing signal loss due to B(1) inhomogeneity. RF pulses in polarization transfer were also used for voxel selection of protons with gradient fields. The transferred (13)C magnetization was refocused by additional refocusing adiabatic pulses. With the intravenous infusion of D-[1-(13)C]glucose solution, (13)C NMR spectra from a 30 mL voxel were acquired for the resonances of C1 of glucose, C2,3,4 of glutamate and glutamine. The time-resolved turnover of glutamate, glutamine and aspartate from intravenously infused D-[1-(13)C]glucose at a temporal resolution of 12 min was demonstrated with excellent spectral resolution and signal-to-noise ratio. Typically, the half-height linewidth of the decoupled (13)C peaks was approximately 4 Hz. Data obtained with infusion of sodium [2-(13)C]acetate using the proposed polarization transfer method and data from the carboxylic carbon region using non-localized acquisition are also presented.
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Affiliation(s)
- Shizhe Li
- National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
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12
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Sela N, Degani H, Frydman L. Ultrafast 2D NMR spectroscopy using sinusoidal gradients: principles and ex vivo brain investigations. Magn Reson Med 2005; 52:893-7. [PMID: 15389964 DOI: 10.1002/mrm.20204] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A new methodology capable of delivering complete 2D NMR spectra within a single scan was recently introduced. The resulting potential gain in time resolution could open new opportunities for in vivo spectroscopy, provided that the technical demands of the methodology are satisfied by the corresponding hardware. Foremost among these demands are the relatively short switching times expected from the applied gradient-echo trains. These rapid transitions may be particularly difficult to accomplish on imaging systems. As a step toward solving this problem, we assessed the possibility of replacing the square-wave gradient train currently used during the course of the acquisition by a shaped sinusoidal gradient. Examples of the implementation of this protocol are given, and successful ultrafast acquisitions of 2D NMR spectra with suitable spectral widths on a microimaging probe (for both phantom solutions and ex vivo mouse brains) are demonstrated.
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Affiliation(s)
- Noa Sela
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
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13
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Yang J, Li CQ, Shen J. In vivo detection of cortical GABA turnover from intravenously infused [1-13C]D-glucose. Magn Reson Med 2005; 53:1258-67. [PMID: 15906278 DOI: 10.1002/mrm.20473] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In this study [2-(13)C] gamma-aminobutyric acid (GABA) was spectrally resolved in vivo and detected simultaneously with [4-(13)C]glutamate (Glu) and [4-(13)C]glutamine (Gln) in the proton spectra obtained from a localized 40 microL voxel in rat neocortex with the use of an adiabatic (1)H-observed, (13)C-edited (POCE) spectroscopy method and an 89-mm-bore vertical 11.7 Tesla microimager. The time-resolved kinetics of (13)C label incorporation from intravenously infused [1-(13)C]glucose into [4-(13)C]Glu, [4-(13)C]Gln, and [2-(13)C]GABA were measured after acute administration of gabaculine, a potent and specific inhibitor of GABA-transaminase. In contrast to previous observations of a rapid turnover of [2-(13)C]GABA from [1-(13)C]glucose in intact rat brain, the rate of (13)C incorporation from [1-(13)C]glucose into [2-(13)C]GABA in the gabaculine-treated rats was found to be significantly reduced as a result of the blockade of the GABA shunt.
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Affiliation(s)
- Jehoon Yang
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, Maryland 20892, USA
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14
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Méric P, Autret G, Doan BT, Gillet B, Sébrié C, Beloeil JC. In vivo 2D magnetic resonance spectroscopy of small animals. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2004; 17:317-38. [PMID: 15625585 DOI: 10.1007/s10334-004-0084-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Revised: 11/02/2004] [Accepted: 11/02/2004] [Indexed: 01/05/2023]
Abstract
Localized in vivo NMR spectroscopy, chemical shift imaging or multi-voxel spectroscopy are potentially useful tools in small animals that are complementary to MRI, adding biochemical information to the mainly anatomical data provided by imaging of water protons. However the contribution of such methods remains hampered by the low spectral resolution of the in vivo 1D spectra. Two-dimensional methods widely developed for in vitro studies have been proposed as suitable approaches to overcome these limitations in resolution. The different homonuclear and heteronuclear sequences adapted to in vivo studies are reviewed. Their specific contributions to the spectral resolution of spectroscopic data and their limitations for in vivo investigations are discussed. The applications to experimental models of pathological processes or pharmacological treatment in mainly brain and muscle are presented. According to their combined sensitivity, acquisition duration and spatial resolution, the heteronuclear 2D experiments, which are mainly used for 1H detected-13C spectroscopy after administration of 13C-labeled compounds, appear to be less efficient than 1H detected-13C 1D methods at high field. However, the applications of 2D proton homonuclear methods show that they remain the best tools for in vivo studies when an improved resolution is required.
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Affiliation(s)
- P Méric
- Laboratoire de RMN Biologique, ICSN-CNRS, Avenue de la Terrasse, 91198, Gif sur Yvette, France.
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15
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Pfeuffer J, Juchem C, Merkle H, Nauerth A, Logothetis NK. High-field localized 1H NMR spectroscopy in the anesthetized and in the awake monkey. Magn Reson Imaging 2004; 22:1361-72. [PMID: 15707786 DOI: 10.1016/j.mri.2004.10.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Accepted: 10/08/2004] [Indexed: 02/02/2023]
Abstract
Localized cerebral in vivo 1H NMR spectroscopy (MRS) was performed in the anesthetized as well as the awake monkey using a novel vertical 7 T/60 cm MR system. The increased sensitivity and spectral dispersion gained at high field enabled the quantification of up to 16 metabolites in 0.1- to 1-ml volumes. Quantification was accomplished by using simulations of 18 metabolite spectra and a macromolecule (MM) background spectrum consisting of 12 components. Major cerebral metabolites (concentrations >3 mM) such as glutamate (Glu), N-acetylaspartate (NAA), creatine (Cr)/phosphocreatine (PCr) and myo-inositol (Ins) were identified with an error below 3%; most other metabolites were quantified with errors in the order of 10%. Metabolite ratios were 1.39:1 for total NAA, 1.38:1 for glutamate (Glu)/glutamine (Gln) and 0.09:1 for cholines (Cho) relative to total Cr. Taurine (Tau) was detectable at concentrations lower than 1 mM, while lactate (Lac) remained below the detection limit. The spectral dispersion was sufficient to separate metabolites of similar spectral patterns, such as Gln and Glu, N-acetylaspartylglutamate (NAAG) and NAA, and PCr-Cr. MRS in the awake monkey required the development and refinement of acquisition and correction strategies to minimize magnetic susceptibility artifacts induced by respiration and movement of the mouth or body. Periods with major motion artifacts were rejected, while a frequency/phase correction was performed on the remaining single spectra before averaging. In resting periods, both spectral amplitude and line width, that is, the voxel shim, were unaffected permitting reliable measurements. The corrected spectra obtained from the awake monkey afforded the reliable detection of 6-10 cerebral metabolites of 1-ml volumes.
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Affiliation(s)
- Josef Pfeuffer
- Department of Physiology of Cognitive Processes, Max-Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany.
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Boumezbeur F, Besret L, Valette J, Vaufrey F, Henry PG, Slavov V, Giacomini E, Hantraye P, Bloch G, Lebon V. NMR measurement of brain oxidative metabolism in monkeys using 13C-labeled glucose without a 13C radiofrequency channel. Magn Reson Med 2004; 52:33-40. [PMID: 15236364 DOI: 10.1002/mrm.20129] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We detected glutamate C4 and C3 labeling in the monkey brain during an infusion of [U-13C6]glucose, using a simple 1H PRESS sequence without 13C editing or decoupling. Point-resolved spectroscopy (PRESS) spectra revealed decreases in 12C-bonded protons, and increases in 13C-bonded protons of glutamate. To take full advantage of the simultaneous detection of 12C- and 13C-bonded 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 12C and 13C. Signal changes were mainly attributed to 12C- and 13C-bonded protons of glutamate. As a result, we were able to measure the tricarboxylic acid (TCA) cycle flux in a 3.9 cm3 voxel centered in the monkey brain on a whole-body 3 Tesla system (VTCA = 0.55 +/- 0.04 micromol x g(-1) x 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 13C radiofrequency (RF) channel.
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Henry PG, Tkác I, Gruetter R. 1H-localized broadband 13C NMR spectroscopy of the rat brain in vivo at 9.4 T. Magn Reson Med 2004; 50:684-92. [PMID: 14523952 DOI: 10.1002/mrm.10601] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Localized (13)C NMR spectra were obtained from the rat brain in vivo over a broad spectral range (15-100 ppm) with minimal chemical-shift displacement error (<10%) using semi-adiabatic distortionless enhancement by polarization transfer (DEPT) combined with (1)H localization. A new gradient dephasing scheme was employed to eliminate unwanted coherences generated by DEPT when using surface coils with highly inhomogeneous B(1) fields. Excellent sensitivity was evident from the simultaneous detection of natural abundance signals for N-acetylaspartate, myo-inositol, and glutamate in the rat brain in vivo at 9.4 T. After infusion of (13)C-labeled glucose, up to 18 (13)C resonances were simultaneously measured in the rat brain, including glutamate C2, C3, C4, glutamine C2, C3, C4, aspartate C2, C3, glucose C1, C6, N-acetyl-aspartate C2, C3, C6, as well as GABA C2, lactate C3, and alanine C3. (13)C-(13)C multiplets corresponding to multiply labeled compounds were clearly observed, suggesting that extensive isotopomer analysis is possible in vivo. This unprecedented amount of information will be useful for metabolic modeling studies aimed at understanding brain energy metabolism and neurotransmission in the rodent brain.
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Affiliation(s)
- Pierre-Gilles Henry
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota Medical School, Minneapolis Minnesota
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Mancini L, Payne GS, Leach MO. Comparison of polarization transfer sequences for enhancement of signals in clinical 31P MRS studies. Magn Reson Med 2003; 50:578-88. [PMID: 12939766 DOI: 10.1002/mrm.10551] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Several (31)P MRS studies in tumors in vivo have shown that levels of phosphocholine (PC) and other phosphomonoesters (PME) and phosphodiesters (PDE) are useful prognostic or early-response indicators. To improve sensitivity for such measurements, four polarization transfer (PT) sequences (insensitive nuclei enhanced by PT (INEPT), distortionless enhancement by PT (DEPT), reverse-INEPT, and heteronuclear single-quantum coherence (HSQC)) were assessed theoretically and experimentally. The presence of homonuclear ((1)H-(1)H) and heteronuclear ((31)P-(1)H) couplings of similar magnitude makes theoretical analysis very sensitive to precise model parameters, especially for the (1)H-detected sequences. The (1)H-(1)H coupling causes the splitting of (1)H peaks, and hence reduces the proton spectral resolution. This effect and a 50% signal loss from gradient-enhanced water suppression negate the usual advantages of (1)H-detection. Among the PT methods, INEPT gave the higher signal enhancement. However, T(2) losses during the long echo times (TEs) required by the weak coupling limited the resulting signals from PC.
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Affiliation(s)
- Laura Mancini
- Cancer Research UK Clinical Magnetic Resonance Research Group, Institute of Cancer Research, and Royal Marsden NHS Trust, Sutton, Surrey, UK.
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Choi IY, Lee SP, Guilfoyle DN, Helpern JA. In vivo NMR studies of neurodegenerative diseases in transgenic and rodent models. Neurochem Res 2003; 28:987-1001. [PMID: 12737523 DOI: 10.1023/a:1023370104289] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In vivo magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) provide unique quality to attain neurochemical, physiological, anatomical, and functional information non-invasively. These techniques have been increasingly applied to biomedical research and clinical usage in diagnosis and prognosis of diseases. The ability of MRS to detect early yet subtle changes of neurochemicals in vivo permits the use of this technology for the study of cerebral metabolism in physiological and pathological conditions. Recent advances in MR technology have further extended its use to assess the etiology and progression of neurodegeneration. This review focuses on the current technical advances and the applications of MRS and MRI in the study of neurodegenerative disease animal models including amyotrophic lateral sclerosis, Alzheimer's, Huntington's, and Parkinson's diseases. Enhanced MR measurable neurochemical parameters in vivo are described in regard to their importance in neurodegenerative disorders and their investigation into the metabolic alterations accompanying the pathogenesis of neurodegeneration.
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Affiliation(s)
- In-Young Choi
- The Nathan S. Kline Institute, Center for Advanced Brain Imaging, Orangeburg, New York 10962, USA.
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Abstract
Localized 13C nuclear magnetic resonance (NMR) spectroscopy provides a unique window for studying cerebral carbohydrate metabolism through, e.g. the completely non-invasive measurement of cerebral glucose and glycogen metabolism. In addition, label incorporation into amino acid neurotransmitters such as glutamate (Glu), GABA and aspartate can be measured providing information on Krebs cycle flux and oxidative metabolism. Given the compartmentation of key enzymes such as pyruvate carboxylase and glutamine synthetase, the detection of label incorporation into glutamine indicated that neuronal and glial metabolism can be measured in vivo. The purpose of this paper is to provide a critical overview of these recent advances into measuring compartmentation of brain energy metabolism using localized in vivo 13C NMR spectroscopy. The studies reviewed herein showed that anaplerosis is significant in brain, as is oxidative ATP generation in glia and the rate of glial glutamine synthesis attributed to the replenishment of the neuronal Glu pool and that brain glycogen metabolism is slow under resting conditions. This new modality promises to provide a new investigative tool to study aspects of normal and diseased brain hitherto unaccessible, such as the interplay between glutamatergic action, glucose and glycogen metabolism during brain activation, and the derangements thereof in patients with hepatic encephalopathy, neurodegenerative diseases and diabetes.
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Affiliation(s)
- Rolf Gruetter
- Department of Radiology, Center for MR Research, University of Minnesota, 2021 6th Street SE, Minneapolis, MN 55455, USA.
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Abstract
A new scheme is proposed to edit separately glutamate C(3) and C(4) resonances of (1)H bound to (13)C, in order to resolve these two signals which overlap at intermediate magnetic fields (1.5 T-3 T), commonly available for human brain studies. The two edited spectra are obtained by combining the individual acquisitions from a four-scan measurement in two different ways. The four acquisitions correspond to the two steps of the classical POCE scheme combined with another two-scan module, where the relative phases of the C(3) and C(4) (1)H resonances are manipulated using zero quantum and double quantum coherence pathways. This new technique exhibits the same sensitivity as POCE and allows the (13)C labeling of C(3) and C(4) glutamate from [1-(13)C]glucose to be monitored separately in the rat brain at 3 T.
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Affiliation(s)
- P G Henry
- CEA, Service Hospitalier Frédéric Joliot, Département de Recherche Médicale, Orsay, France
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