1
|
Zhou J, Sun W, Li H, Song X, Xu D, Xu H. Application of 5T glutamate chemical exchange saturation transfer imaging in brain tumors: preliminary results. J Neurooncol 2024; 169:581-589. [PMID: 38958848 DOI: 10.1007/s11060-024-04759-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Accepted: 06/25/2024] [Indexed: 07/04/2024]
Abstract
PURPOSE Glutamate chemical exchange saturation transfer (GluCEST) is a non-invasive CEST imaging technique for detecting glutamate levels in tissues. We aimed to investigate the reproducibility of the 5T GluCEST technique in healthy volunteers and preliminarily explore its potential clinical application in patients with brain tumors. METHODS Ten volunteers (4 males, mean age 29 years) underwent three 5T GluCEST imaging scans. The reproducibility of the three imaging GluCEST measurements was assessed using one-way repeated measures analysis of variance (ANOVA), generalized estimating equations, and linear mixed models. Twenty-eight patients with brain tumors (10 males, mean age 54 years) underwent a single GluCEST scan preoperatively, and t-tests were used to compare the differences in GluCEST values between different brain tumors. In addition, the diagnostic accuracy of GluCEST values in differentiating brain tumors was assessed using the receiver work characteristics (ROC) curve. RESULTS The coefficients of variation of GluCEST values in healthy volunteers were less than 5% for intra-day, inter-day, and within-subjects and less than 10% for between-subjects. High-grade gliomas (HGG) had higher GluCEST values compared to low-grade gliomas (LGG) (P < 0.001). In addition, cerebellopontine angle (CPA) meningiomas had higher GluCEST values than acoustic neuromas (P < 0.001). The area under the curve (AUC) of the GluCEST value for differentiating CPA meningioma from acoustic neuroma was 0.93. CONCLUSION 5T GluCEST images are highly reproducible in healthy brains. In addition, the 5T GluCEST technique has potential clinical applications in differentiating LGG from HGG and CPA meningiomas from acoustic neuromas.
Collapse
Affiliation(s)
- Jie Zhou
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Wenbo Sun
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Huan Li
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Xiaopeng Song
- Central Research Institute, United Imaging Healthcare, 2258 Chengbei Rd., Jiading District, Shanghai, 201807, China
| | - Dan Xu
- Department of Nuclear Medicine, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China.
| | - Haibo Xu
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China.
| |
Collapse
|
2
|
Bitencourt AGV, Bhowmik A, Marcal Filho EFDL, Lo Gullo R, Mazaheri Y, Kapetas P, Eskreis-Winkler S, Young R, Pinker K, Thakur SB. Deuterium MR spectroscopy: potential applications in oncology research. BJR Open 2024; 6:tzae019. [PMID: 39165295 PMCID: PMC11333568 DOI: 10.1093/bjro/tzae019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 07/23/2024] [Accepted: 07/30/2024] [Indexed: 08/22/2024] Open
Abstract
Metabolic imaging in clinical practice has long relied on PET with fluorodeoxyglucose (FDG), a radioactive tracer. However, this conventional method presents inherent limitations such as exposure to ionizing radiation and potential diagnostic uncertainties, particularly in organs with heightened glucose uptake like the brain. This review underscores the transformative potential of traditional deuterium MR spectroscopy (MRS) when integrated with gradient techniques, culminating in an advanced metabolic imaging modality known as deuterium MRI (DMRI). While recent advancements in hyperpolarized MRS hold promise for metabolic analysis, their widespread clinical usage is hindered by cost constraints and the availability of hyperpolarizer devices or facilities. DMRI, also denoted as deuterium metabolic imaging (DMI), represents a pioneering, single-shot, and noninvasive paradigm that fuses conventional MRS with nonradioactive deuterium-labelled substrates. Extensively tested in animal models and patient cohorts, particularly in cases of brain tumours, DMI's standout feature lies in its seamless integration into standard clinical MRI scanners, necessitating only minor adjustments such as radiofrequency coil tuning to the deuterium frequency. DMRI emerges as a versatile tool for quantifying crucial metabolites in clinical oncology, including glucose, lactate, glutamate, glutamine, and characterizing IDH mutations. Its potential applications in this domain are broad, spanning diagnostic profiling, treatment response monitoring, and the identification of novel therapeutic targets across diverse cancer subtypes.
Collapse
Affiliation(s)
- Almir Galvão Vieira Bitencourt
- Imaging Department, A. C. Camargo Cancer Center, São Paulo, 01525-001, Brazil
- Diagnósticos da América S.A., São Paulo, 04321-120, Brazil
| | - Arka Bhowmik
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States
| | | | - Roberto Lo Gullo
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States
| | - Yousef Mazaheri
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States
| | - Panagiotis Kapetas
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, 1090 Vienna, Austria
| | - Sarah Eskreis-Winkler
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States
| | - Robert Young
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States
| | - Katja Pinker
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States
| | - Sunitha B Thakur
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, United States
| |
Collapse
|
3
|
He J, Wang D, Ban M, Kong L, Xiao Q, Yuan F, Zhu X. Regional metabolic heterogeneity in anterior cingulate cortex in major depressive disorder: A multi-voxel 1H magnetic resonance spectroscopy study. J Affect Disord 2022; 318:263-271. [PMID: 36087788 DOI: 10.1016/j.jad.2022.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 08/29/2022] [Accepted: 09/05/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND Previous studies have shown major depressive disorder (MDD) is associated with altered neuro-metabolites in the anterior cingulate cortex (ACC). However, the regional metabolic heterogeneity in the ACC in individuals with MDD remains unclear. METHODS We recruited 59 first-episode, treatment-naive young adults with MDD and 50 healthy controls who underwent multi-voxel 1H-MRS scanning at 3 T (Tesla) with voxels placed in the ACC, which was divided into two subregions, pregenual ACC (pACC) and anterior midcingulate cortex (aMCC). Between and within-subjects metabolite concentration variations were analyzed with SPSS. RESULTS Compared with control subjects, patients with MDD exhibited higher glutamate (Glu) and glutamine (Gln) levels in the pACC and higher myo-inositol (MI) level in the aMCC. We observed higher Glu and Gln levels and lower N-acetyl-aspartate (NAA) level in the pACC than those in the aMCC in both MDD and healthy control (HC) groups. More importantly, the metabolite concentration gradients of Glu, Gln and NAA were more pronounced in MDD patients relative to HCs. In the MDD group, the MI level in the aMCC positively correlated with the age of onset. LIMITATIONS The use of the relative concentration of metabolites constitutes a key study limitation. CONCLUSIONS We observed inconsistent alterations and distribution of neuro-metabolites concentration in the pACC and aMCC, revealing regional metabolic heterogeneity of ACC in first-episode, treatment-naive young individuals with MDD. These results provided new evidence for abnormal neuro-metabolites of ACC in the pathophysiology of MDD and suggested that pACC and aMCC might play different roles in MDD.
Collapse
Affiliation(s)
- Jincheng He
- Department of Radiology, Xiangya Hospital, Central South University, Changsha, China
| | - Dongcui Wang
- Department of Radiology, Xiangya Hospital, Central South University, Changsha, China
| | - Meiting Ban
- Department of Radiology, Xiangya Hospital, Central South University, Changsha, China
| | - Lingyu Kong
- Department of Radiology, Xiangya Hospital, Central South University, Changsha, China
| | - Qian Xiao
- Mental Health Centre, Xiangya Hospital, Central South University, Changsha, China
| | - Fulai Yuan
- Health Management Center, Xiangya Hospital, Central South University, Changsha, China
| | - Xueling Zhu
- Department of Radiology, Xiangya Hospital, Central South University, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.
| |
Collapse
|
4
|
McCarthy L, Verma G, Hangel G, Neal A, Moffat BA, Stockmann JP, Andronesi OC, Balchandani P, Hadjipanayis CG. Application of 7T MRS to High-Grade Gliomas. AJNR Am J Neuroradiol 2022; 43:1378-1395. [PMID: 35618424 PMCID: PMC9575545 DOI: 10.3174/ajnr.a7502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 02/11/2022] [Indexed: 01/26/2023]
Abstract
MRS, including single-voxel spectroscopy and MR spectroscopic imaging, captures metabolites in high-grade gliomas. Emerging evidence indicates that 7T MRS may be more sensitive to aberrant metabolic activity than lower-field strength MRS. However, the literature on the use of 7T MRS to visualize high-grade gliomas has not been summarized. We aimed to identify metabolic information provided by 7T MRS, optimal spectroscopic sequences, and areas for improvement in and new applications for 7T MRS. Literature was found on PubMed using "high-grade glioma," "malignant glioma," "glioblastoma," "anaplastic astrocytoma," "7T," "MR spectroscopy," and "MR spectroscopic imaging." 7T MRS offers higher SNR, modestly improved spatial resolution, and better resolution of overlapping resonances. 7T MRS also yields reduced Cramér-Rao lower bound values. These features help to quantify D-2-hydroxyglutarate in isocitrate dehydrogenase 1 and 2 gliomas and to isolate variable glutamate, increased glutamine, and increased glycine with higher sensitivity and specificity. 7T MRS may better characterize tumor infiltration and treatment effect in high-grade gliomas, though further study is necessary. 7T MRS will benefit from increased sample size; reductions in field inhomogeneity, specific absorption rate, and acquisition time; and advanced editing techniques. These findings suggest that 7T MRS may advance understanding of high-grade glioma metabolism, with reduced Cramér-Rao lower bound values and better measurement of smaller metabolite signals. Nevertheless, 7T is not widely used clinically, and technical improvements are necessary. 7T MRS isolates metabolites that may be valuable therapeutic targets in high-grade gliomas, potentially resulting in wider ranging neuro-oncologic applications.
Collapse
Affiliation(s)
- L McCarthy
- From the Department of Neurosurgery (L.M., C.G.H.), Icahn School of Medicine at Mount Sinai, Mount Sinai Health System, New York, New York
| | - G Verma
- BioMedical Engineering and Imaging Institute (G.V., P.B.), Icahn School of Medicine at Mount Sinai, New York, New York
| | - G Hangel
- Department of Neurosurgery (G.H.)
- High-field MR Center (G.H.), Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - A Neal
- Department of Medicine (A.N.), Royal Melbourne Hospital, University of Melbourne, Melbourne, Australia
- Department of Neurology (A.N.), Royal Melbourne Hospital, Melbourne, Australia
| | - B A Moffat
- The Melbourne Brain Centre Imaging Unit (B.A.M.), Department of Radiology, The University of Melbourne, Melbourne, Australia
| | - J P Stockmann
- A. A. Martinos Center for Biomedical Imaging (J.P.S., O.C.A.), Massachusetts General Hospital, Charlestown, Massachusetts
- Harvard Medical School (J.P.S., O.C.A.), Boston, Massachusetts
| | - O C Andronesi
- A. A. Martinos Center for Biomedical Imaging (J.P.S., O.C.A.), Massachusetts General Hospital, Charlestown, Massachusetts
- Harvard Medical School (J.P.S., O.C.A.), Boston, Massachusetts
| | - P Balchandani
- BioMedical Engineering and Imaging Institute (G.V., P.B.), Icahn School of Medicine at Mount Sinai, New York, New York
| | - C G Hadjipanayis
- From the Department of Neurosurgery (L.M., C.G.H.), Icahn School of Medicine at Mount Sinai, Mount Sinai Health System, New York, New York
| |
Collapse
|
5
|
Li H, Heise KF, Chalavi S, Puts NAJ, Edden RAE, Swinnen SP. The role of MRS-assessed GABA in human behavioral performance. Prog Neurobiol 2022; 212:102247. [PMID: 35149113 DOI: 10.1016/j.pneurobio.2022.102247] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 01/25/2022] [Accepted: 02/04/2022] [Indexed: 01/16/2023]
Abstract
Understanding the neurophysiological mechanisms that drive human behavior has been a long-standing focus of cognitive neuroscience. One well-known neuro-metabolite involved in the creation of optimal behavioral repertoires is GABA, the main inhibitory neurochemical in the human brain. Converging evidence from both animal and human studies indicates that individual variations in GABAergic function are associated with behavioral performance. In humans, one increasingly used in vivo approach to measuring GABA levels is through Magnetic Resonance Spectroscopy (MRS). However, the implications of MRS measures of GABA for behavior remain poorly understood. In this respect, it is yet to be determined how GABA levels within distinct task-related brain regions of interest account for differences in behavioral performance. This review summarizes findings from cross-sectional studies that determined baseline MRS-assessed GABA levels and examined their associations with performance on various behaviors representing the perceptual, motor and cognitive domains, with a particular focus on healthy participants across the lifespan. Overall, the results indicate that MRS-assessed GABA levels play a pivotal role in various domains of behavior. Even though some converging patterns emerge, it is challenging to draw comprehensive conclusions due to differences in behavioral task paradigms, targeted brain regions of interest, implemented MRS techniques and reference compounds used. Across all studies, the effects of GABA levels on behavioral performance point to generic and partially independent functions that refer to distinctiveness, interference suppression and cognitive flexibility. On one hand, higher baseline GABA levels may support the distinctiveness of neural representations during task performance and better coping with interference and suppression of preferred response tendencies. On the other hand, lower baseline GABA levels may support a reduction of inhibition, leading to higher cognitive flexibility. These effects are task-dependent and appear to be mediated by age. Nonetheless, additional studies using emerging advanced methods are required to further clarify the role of MRS-assessed GABA in behavioral performance.
Collapse
Affiliation(s)
- Hong Li
- Movement Control & Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Belgium; KU Leuven Brain Institute (LBI), KU Leuven, Belgium.
| | - Kirstin-Friederike Heise
- Movement Control & Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Belgium; KU Leuven Brain Institute (LBI), KU Leuven, Belgium; Department of Health Sciences and Research, Medical University of South Carolina, Charleston, SC, USA.
| | - Sima Chalavi
- Movement Control & Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Belgium; KU Leuven Brain Institute (LBI), KU Leuven, Belgium.
| | - Nicolaas A J Puts
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK; Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK; Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
| | - Richard A E Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Stephan P Swinnen
- Movement Control & Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Belgium; KU Leuven Brain Institute (LBI), KU Leuven, Belgium.
| |
Collapse
|
6
|
Reid MA, Forloines MR, Salibi N. Reproducibility of 7-T brain spectroscopy using an ultrashort echo time STimulated Echo Acquisition Mode sequence and automated voxel repositioning. NMR IN BIOMEDICINE 2022; 35:e4631. [PMID: 34622996 PMCID: PMC8862634 DOI: 10.1002/nbm.4631] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/15/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Establishing the reproducibility of brain MRS is important for clinical studies so that researchers can evaluate changes in metabolites due to treatment or the course of a disease and better understand the brain in healthy and disordered states. Prior 7-T MRS reproducibility studies using the stimulated echo acquisition mode (STEAM) sequence have focused on the anterior cingulate cortex or posterior cingulate cortex and precuneus. The purpose of this study was to evaluate the reproducibility of metabolite measurements in the dorsolateral prefrontal cortex (DLPFC) using an ultrashort echo time (TE) STEAM sequence and automated voxel repositioning. Spectra were acquired during two scan sessions from nine subjects using the AutoAlign method for voxel repositioning. Reproducibility was evaluated with coefficients of variation (CVs) and percentage differences. The mean intrasubject CVs were less than 6% for the major metabolites glutamate, N-acetylaspartate, total creatine, total choline, and myo-inositol. The mean CVs were less than 20% for the smaller signals of GABA, glutamine, glutathione, and taurine. These results indicate that 7-T MRS using a STEAM sequence with ultrashort TE and automated voxel repositioning provides excellent reproducibility of metabolites in the DLPFC.
Collapse
Affiliation(s)
- Meredith A. Reid
- MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, USA
- Alabama Advanced Imaging Consortium, Auburn, Alabama, USA
| | - Martha R. Forloines
- Alzheimer’s Disease Center, Department of Neurology, University of California, Davis, Sacramento, California, USA
| | | |
Collapse
|
7
|
Hangel G, Niess E, Lazen P, Bednarik P, Bogner W, Strasser B. Emerging methods and applications of ultra-high field MR spectroscopic imaging in the human brain. Anal Biochem 2022; 638:114479. [PMID: 34838516 DOI: 10.1016/j.ab.2021.114479] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 10/15/2021] [Accepted: 11/16/2021] [Indexed: 12/21/2022]
Abstract
Magnetic Resonance Spectroscopic Imaging (MRSI) of the brain enables insights into the metabolic changes and fluxes in diseases such as tumors, multiple sclerosis, epilepsy, or hepatic encephalopathy, as well as insights into general brain functionality. However, the routine application of MRSI is mostly hampered by very low signal-to-noise ratios (SNR) due to the low concentrations of metabolites, about 10000 times lower than water. Furthermore, MRSI spectra have a dense information content with many overlapping metabolite resonances, especially for proton MRSI. MRI scanners at ultra-high field strengths, like 7 T or above, offer the opportunity to increase SNR, as well as the separation between resonances, thus promising to solve both challenges. Yet, MRSI at ultra-high field strengths is challenged by decreased B0- and B1-homogeneity, shorter T2 relaxation times, stronger chemical shift displacement errors, and aggravated lipid contamination. Therefore, to capitalize on the advantages of ultra-high field strengths, these challenges must be overcome. This review focuses on the challenges MRSI of the human brain faces at ultra-high field strength, as well as the possible applications to this date.
Collapse
Affiliation(s)
- Gilbert Hangel
- High Field MR Centre, Department of Medical Imaging and Image-Guided Therapy, Medical University of Vienna, Austria; Department of Neurosurgery, Medical University of Vienna, Austria
| | - Eva Niess
- High Field MR Centre, Department of Medical Imaging and Image-Guided Therapy, Medical University of Vienna, Austria
| | - Philipp Lazen
- High Field MR Centre, Department of Medical Imaging and Image-Guided Therapy, Medical University of Vienna, Austria
| | - Petr Bednarik
- High Field MR Centre, Department of Medical Imaging and Image-Guided Therapy, Medical University of Vienna, Austria
| | - Wolfgang Bogner
- High Field MR Centre, Department of Medical Imaging and Image-Guided Therapy, Medical University of Vienna, Austria
| | - Bernhard Strasser
- High Field MR Centre, Department of Medical Imaging and Image-Guided Therapy, Medical University of Vienna, Austria.
| |
Collapse
|
8
|
Finkelman T, Furman-Haran E, Paz R, Tal A. Quantifying the excitatory-inhibitory balance: A comparison of SemiLASER and MEGA-SemiLASER for simultaneously measuring GABA and glutamate at 7T. Neuroimage 2021; 247:118810. [PMID: 34906716 DOI: 10.1016/j.neuroimage.2021.118810] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 10/19/2022] Open
Abstract
The importance of the excitatory-inhibitory (E/I) balance in a wide range of cognitive and behavioral processes has prompted a commensurate interest in methods for reliably quantifying it. Proton Magnetic Resonance Spectroscopy (1H-MRS) remains the only method capable of safely and non-invasively measuring the concentrations of the brain's major excitatory (glutamate) and inhibitory (γ-aminobutyric-acid, GABA) neurotransmitters in-vivo. MRS relies on spectral Mescher-Garwood (MEGA) editing techniques at 3T to distinguish GABA from its overlapping resonances. However, with the increased spectral resolution at ultrahigh field strengths of 7T and above, non-edited spectroscopic techniques become potential viable alternatives to MEGA based approaches, and also address some of their shortcomings, such as signal loss, sensitivity to transmitter inhomogeneities and temporal resolution. We present a comprehensive comparison of both edited and non-edited strategies at 7T for simultaneously quantifying glutamate and GABA from the dorsal anterior cingulate cortex (dACC), and evaluate their reproducibility and relative bias. The combined root-mean-square test-retest reproducibility of Glu and GABA (CVE/I) was as low as 13.3% for unedited MRS at TE=80 ms using SemiLASER localization, while edited MRS at TE=80 ms yielded CVE/I=20% and 21% for asymmetric and symmetric MEGA editing, respectively. An unedited SemiLASER acquisition using a shorter echo time of TE=42 ms yielded CVE/I as low as 24.9%. Our results show that non-edited sequences at an echo time of 80 ms provide better reproducibility than either edited sequences at the same TE, or non-edited sequences at a shorter TE of 42 ms. This is supported by numerical simulations and is driven in part by a pseudo-singlet appearance of the GABA multiplets at TE=80 ms, and the excellent spectral resolution at 7T. Our results uphold a transition to non-edited MRS for monitoring the E/I balance at ultrahigh fields, and stress the importance of using a properly-optimized echo time.
Collapse
Affiliation(s)
- Tal Finkelman
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel; Department of Chemical and Biological Physics, Weizmann Institute of Science, 234 Herzel St., Rehovot 7610001, Israel
| | - Edna Furman-Haran
- Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Rony Paz
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Assaf Tal
- Department of Chemical and Biological Physics, Weizmann Institute of Science, 234 Herzel St., Rehovot 7610001, Israel.
| |
Collapse
|
9
|
Abstract
More than one million people in the United States suffer from seizures that are not controlled with antiseizure medications. Targeted interventions such as surgery and deep brain stimulation can confer seizure reduction or even freedom in many of these patients with drug-resistant epilepsy, but success critically depends on identification of epileptogenic zones through MR imaging. Ultrahigh field imaging facilitates improved sensitivity and resolution across many imaging modalities and may facilitate better detection of epileptic markers than is achieved at lower field strengths. The increasing availability and clinical adoption of ultrahigh field scanners play an important role in characterizing drug-resistant epilepsy and planning for its treatment.
Collapse
Affiliation(s)
- Gaurav Verma
- Biomedical Engineering and Imaging Institute, The Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY 10029, USA.
| | - Bradley N Delman
- Department of Diagnostic, Molecular and Interventional Radiology, The Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1234, New York, NY 10029, USA
| | - Priti Balchandani
- Biomedical Engineering and Imaging Institute, The Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY 10029, USA; Department of Diagnostic, Molecular and Interventional Radiology, The Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1234, New York, NY 10029, USA
| |
Collapse
|
10
|
Transcranial direct current stimulation (tDCS) over the auditory cortex modulates GABA and glutamate: a 7 T MR-spectroscopy study. Sci Rep 2020; 10:20111. [PMID: 33208867 PMCID: PMC7674467 DOI: 10.1038/s41598-020-77111-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 11/04/2020] [Indexed: 02/06/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) is one of the most prominent non-invasive electrical brain stimulation method to alter neuronal activity as well as behavioral processes in cognitive and perceptual domains. However, the exact mode of action of tDCS-related cortical alterations is still unclear as the results of tDCS studies often do not comply with the somatic doctrine assuming that anodal tDCS enhances while cathodal tDCS decreases neuronal excitability. Changes in the regional cortical neurotransmitter balance within the stimulated cortex, measured by excitatory and inhibitory neurotransmitter levels, have the potential to provide direct neurochemical underpinnings of tDCS effects. Here we assessed tDCS-induced modulations of the neurotransmitter concentrations in the human auditory cortex (AC) by using magnetic resonance spectroscopy (MRS) at ultra-high-field (7 T). We quantified inhibitory gamma-amino butyric (GABA) concentration and excitatory glutamate (Glu) and compared changes in the relative concentration of GABA to Glu before and after tDCS application. We found that both, anodal and cathodal tDCS significantly increased the relative concentration of GABA to Glu with individual temporal specificity. Our results offer novel insights for a potential neurochemical mechanism that underlies tDCS-induced alterations of AC processing.
Collapse
|
11
|
Gonen OM, Moffat BA, Kwan P, O'Brien TJ, Desmond PM, Lui E. Reproducibility of Glutamate, Glutathione, and GABA Measurements in vivo by Single-Voxel STEAM Magnetic Resonance Spectroscopy at 7-Tesla in Healthy Individuals. Front Neurosci 2020; 14:566643. [PMID: 33041761 PMCID: PMC7522573 DOI: 10.3389/fnins.2020.566643] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/21/2020] [Indexed: 01/20/2023] Open
Abstract
Background and Purpose Derangements in brain glutamate, glutathione, and γ-amino butyric acid (GABA) are implicated in a range of neurological disorders. Reliable methods to measure these compounds non-invasively in vivo are needed. We evaluated the reproducibility of their measurements in brain regions involved in the default mode network using quantitative MRS at 7-Tesla in healthy individuals. Methods Ten right-handed healthy volunteers underwent 7-Tesla MRI scans on 2 separate days, not more than 2 weeks apart. On each day two scanning sessions took place, with a re-positioning break in between. High-resolution isotropic anatomical scans were acquired prior to each scan, followed by single-voxel 1H-MRS using the STEAM pulse sequence on an 8 mL midline cubic voxel, positioned over the posterior cingulate and precuneus regions. Concentrations were corrected for partial-volume effects. Results Maximal Cramér-Rao lower bounds for glutamate, glutathione, and GABA were 2.0, 8.0, and 14.0%, respectively. Mean coefficients of variation within sessions were 5.9 ± 4.8%, 9.3 ± 7.6%, and 11.5 ± 8.8%, and between sessions were 4.6 ± 4.5%, 8.3 ± 5.7%, and 9.2 ± 8.7%, respectively. The mean (±SD) Dice’s coefficient for voxel overlap was 90 ± 4% within sessions and 86 ± 7% between sessions. Conclusion Glutamate, glutathione, and GABA can be reliably quantified using STEAM MRS at 7-Tesla from the posterior cingulate and precuneus cortices of healthy human subjects. STEAM MRS at 7-Tesla may be used to study the metabolic behavior of this important resting-state hub in various disease states.
Collapse
Affiliation(s)
- Ofer M Gonen
- Department of Neurology, The Royal Melbourne Hospital, Parkville, VIC, Australia.,Department of Medicine and Radiology, The University of Melbourne, Parkville, VIC, Australia.,Department of Neurology, The Alfred Hospital, Melbourne, VIC, Australia
| | - Bradford A Moffat
- Department of Medicine and Radiology, The University of Melbourne, Parkville, VIC, Australia
| | - Patrick Kwan
- Department of Neurology, The Royal Melbourne Hospital, Parkville, VIC, Australia.,Department of Medicine and Radiology, The University of Melbourne, Parkville, VIC, Australia.,Department of Neurology, The Alfred Hospital, Melbourne, VIC, Australia.,Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Terence J O'Brien
- Department of Neurology, The Royal Melbourne Hospital, Parkville, VIC, Australia.,Department of Medicine and Radiology, The University of Melbourne, Parkville, VIC, Australia.,Department of Neurology, The Alfred Hospital, Melbourne, VIC, Australia.,Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Patricia M Desmond
- Department of Medicine and Radiology, The University of Melbourne, Parkville, VIC, Australia.,Department of Radiology, The Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Elaine Lui
- Department of Medicine and Radiology, The University of Melbourne, Parkville, VIC, Australia.,Department of Radiology, The Royal Melbourne Hospital, Parkville, VIC, Australia
| |
Collapse
|
12
|
Affiliation(s)
- Gaurav Verma
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Priti Balchandani
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| |
Collapse
|
13
|
Wijtenburg SA, Rowland LM, Oeltzschner G, Barker PB, Workman CI, Smith GS. Reproducibility of brain MRS in older healthy adults at 7T. NMR IN BIOMEDICINE 2019; 32:e4040. [PMID: 30489668 PMCID: PMC6324949 DOI: 10.1002/nbm.4040] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 10/01/2018] [Accepted: 10/26/2018] [Indexed: 05/21/2023]
Abstract
To date, the majority of MRS reproducibility studies have been conducted in healthy younger adults, with only a few conducted in older adults at 3 T. With the growing interest in applying MRS methods to study the longitudinal course and effects of treatments in neurodegenerative disease, it is important to establish reproducibility in age-matched controls, especially in older individuals. In this study, spectroscopic data were acquired using a stimulated echo acquisition mode (STEAM) localization technique in two regions (anterior and posterior cingulate cortices-ACC, PCC, respectively) in 10 healthy, cognitively normal older adults (64 ± 8.1 years). Reproducibility was assessed via mean coefficients of variation (CVs) and relative differences (RDs) calculated across two visits performed 2-3 months apart. Metabolites with high signal-to-noise ratio (SNR) such as NAA, tCho, and Glu had mean CVs of 10% or less and mean RDs of 15% or less across both regions. Metabolites with lower SNR such as GABA and Gln had slightly higher mean CVs of 22% or less and mean RDs of 27% or less across both regions. These results demonstrate the feasibility of acquiring MRS data at 7 T in older subjects, and establish that the spectroscopic data are reproducible in both the ACC and PCC in older, healthy subjects to the same extent as in previous studies in young subjects.
Collapse
Affiliation(s)
- S. Andrea Wijtenburg
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD
| | - Laura M. Rowland
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD
- Department of Psychology, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Georg Oeltzschner
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD
- F.M. Kirby Research Center for Functional Brain Imaging, The Kennedy Krieger Institute, Baltimore, MD
| | - Peter B. Barker
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD
- F.M. Kirby Research Center for Functional Brain Imaging, The Kennedy Krieger Institute, Baltimore, MD
| | - Clifford I. Workman
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - Gwenn S. Smith
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD
| |
Collapse
|
14
|
Alizai H, Chang G, Regatte RR. MR Imaging of the Musculoskeletal System Using Ultrahigh Field (7T) MR Imaging. PET Clin 2019; 13:551-565. [PMID: 30219187 DOI: 10.1016/j.cpet.2018.05.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
MR imaging is an indispensable instrument for the diagnosis of musculoskeletal diseases. In vivo MR imaging at 7T offers many advantages, including increased signal-to-noise ratio, higher spatial resolution, improved spectral resolution for spectroscopy, improved sensitivity for X-nucleus imaging, and decreased image acquisition times. There are also however technical challenges of imaging at a higher field strength compared with 1.5 and 3T MR imaging systems. We discuss the many potential opportunities as well as the challenges presented by 7T MR imaging systems and highlight recent developments in in vivo research imaging of musculoskeletal applications in general and cartilage, skeletal muscle, and bone in particular.
Collapse
Affiliation(s)
- Hamza Alizai
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, New York, NY 10016, USA.
| | - Gregory Chang
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, New York, NY 10016, USA
| | - Ravinder R Regatte
- Department of Radiology, New York University Langone Medical Center, 660 First Avenue, New York, NY 10016, USA
| |
Collapse
|
15
|
Ladd ME, Bachert P, Meyerspeer M, Moser E, Nagel AM, Norris DG, Schmitter S, Speck O, Straub S, Zaiss M. Pros and cons of ultra-high-field MRI/MRS for human application. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:1-50. [PMID: 30527132 DOI: 10.1016/j.pnmrs.2018.06.001] [Citation(s) in RCA: 267] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 05/08/2023]
Abstract
Magnetic resonance imaging and spectroscopic techniques are widely used in humans both for clinical diagnostic applications and in basic research areas such as cognitive neuroimaging. In recent years, new human MR systems have become available operating at static magnetic fields of 7 T or higher (≥300 MHz proton frequency). Imaging human-sized objects at such high frequencies presents several challenges including non-uniform radiofrequency fields, enhanced susceptibility artifacts, and higher radiofrequency energy deposition in the tissue. On the other side of the scale are gains in signal-to-noise or contrast-to-noise ratio that allow finer structures to be visualized and smaller physiological effects to be detected. This review presents an overview of some of the latest methodological developments in human ultra-high field MRI/MRS as well as associated clinical and scientific applications. Emphasis is given to techniques that particularly benefit from the changing physical characteristics at high magnetic fields, including susceptibility-weighted imaging and phase-contrast techniques, imaging with X-nuclei, MR spectroscopy, CEST imaging, as well as functional MRI. In addition, more general methodological developments such as parallel transmission and motion correction will be discussed that are required to leverage the full potential of higher magnetic fields, and an overview of relevant physiological considerations of human high magnetic field exposure is provided.
Collapse
Affiliation(s)
- Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Peter Bachert
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Armin M Nagel
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - David G Norris
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Sebastian Schmitter
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany.
| | - Oliver Speck
- Department of Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany; German Center for Neurodegenerative Diseases, Magdeburg, Germany; Center for Behavioural Brain Sciences, Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany.
| | - Sina Straub
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Moritz Zaiss
- High-Field Magnetic Resonance Center, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany.
| |
Collapse
|
16
|
Nanga RPR, DeBrosse C, Kumar D, Roalf D, McGeehan B, D'Aquilla K, Borthakur A, Hariharan H, Reddy D, Elliott M, Detre JA, Epperson CN, Reddy R. Reproducibility of 2D GluCEST in healthy human volunteers at 7 T. Magn Reson Med 2018; 80:2033-2039. [PMID: 29802635 PMCID: PMC6107408 DOI: 10.1002/mrm.27362] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 04/11/2018] [Accepted: 04/24/2018] [Indexed: 01/06/2023]
Abstract
PURPOSE To investigate the reproducibility of gray and white matter glutamate contrast of a brain slice among a small group of healthy volunteers by using the 2D single-slice glutamate CEST (GluCEST) imaging technique. METHODS Six healthy volunteers were scanned multiple times for within-day and between-day reproducibility. One more volunteer was scanned for within-day reproducibility at 7T MRI. Glutamate CEST contrast measurements were calculated for within subjects and among the subjects and the coefficient of variations are reported. RESULTS The GluCEST measurements were highly reproducible in the gray and white matter area of the brain slice, whether it was within-day or between-day with a coefficient of variation of less than 5%. CONCLUSION This preliminary study in a small group of healthy volunteers shows a high degree of reproducibility of GluCEST MRI in brain and holds promise for implementation in studying age-dependent changes in the brain.
Collapse
Affiliation(s)
- Ravi Prakash Reddy Nanga
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Catherine DeBrosse
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Dushyant Kumar
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - David Roalf
- Department of PsychiatryUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Brendan McGeehan
- Department of PsychiatryUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Kevin D'Aquilla
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Arijitt Borthakur
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Hari Hariharan
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Damodara Reddy
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Mark Elliott
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - John A. Detre
- Department of NeurologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Cynthia Neill Epperson
- Department of PsychiatryUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Ravinder Reddy
- Department of RadiologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| |
Collapse
|
17
|
Magnusson PO, Boer VO, Marsman A, Paulson OB, Hanson LG, Petersen ET. Gamma-aminobutyric acid edited echo-planar spectroscopic imaging (EPSI) with MEGA-sLASER at 7T. Magn Reson Med 2018; 81:773-780. [PMID: 30159924 PMCID: PMC6646902 DOI: 10.1002/mrm.27450] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 07/14/2018] [Accepted: 07/17/2018] [Indexed: 11/08/2022]
Abstract
PURPOSE For rapid spatial mapping of gamma-aminobutyric acid (GABA) at the increased sensitivity and spectral separation for ultra-high magnetic field strength (7 tesla [T]), an accelerated edited magnetic resonance spectroscopic imaging technique was developed and optimized for the human brain at 7 T. METHODS A MEGA-sLASER sequence was used for GABA editing and volume selection to maximize editing efficiency and minimize chemical shift displacement errors. To accommodate the high bandwidth requirements at 7 T, a single-shot echo planar readout was used for rapid simultaneous encoding of the temporal dimension and 1 spatial. B0 and B1 field aspects specific for 7 T were studied together with correction procedures, and feasibility of the EPSI MEGA-sLASER technique was tested in vivo in 5 healthy subjects. RESULTS Localized edited spectra could be measured in all subjects giving spatial GABA signal distributions over a central brain region, having 45- to 50-Hz spatial intervoxel B0 field variations and up to 30% B1 field deviations. MEGA editing was found unaffected by the B0 inhomogeneities for the optimized sequence. The correction procedures reduced effects of intervoxel B0 inhomogeneities, corrected for spatial editing efficiency variations, and compensated for GABA resonance phase and frequency shifts from subtle motion and acquisition instabilities. The optimized oscillating echo-planar gradient scheme permitted full spectral acquisition at 7 T and exhibited minimal spectral-spatial ghosting effects for the selected brain region. CONCLUSION The EPSI MEGA-sLASER technique was shown to provide time-efficient mapping of regional variations in cerebral GABA in a central volume of interest with spatial B1 and B0 field variations typical for 7 T.
Collapse
Affiliation(s)
- Peter O Magnusson
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark
| | - Vincent O Boer
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark
| | - Anouk Marsman
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark
| | - Olaf B Paulson
- Neurobiology Research Unit, Department of Neurology, The Neuroscience Center, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Lars G Hanson
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark.,Center for Magnetic Resonance, DTU Elektro, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Esben T Petersen
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark.,Center for Magnetic Resonance, DTU Elektro, Technical University of Denmark, Kgs. Lyngby, Denmark
| |
Collapse
|
18
|
Posporelis S, Coughlin JM, Marsman A, Pradhan S, Tanaka T, Wang H, Varvaris M, Ward R, Higgs C, Edwards JA, Ford CN, Kim PK, Lloyd AM, Edden RAE, Schretlen DJ, Cascella NG, Barker PB, Sawa A. Decoupling of Brain Temperature and Glutamate in Recent Onset of Schizophrenia: A 7T Proton Magnetic Resonance Spectroscopy Study. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2018; 3:248-254. [PMID: 29486866 PMCID: PMC5836506 DOI: 10.1016/j.bpsc.2017.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 03/23/2017] [Accepted: 04/10/2017] [Indexed: 01/09/2023]
Abstract
BACKGROUND Converging evidence suggests that cerebral metabolic and cellular homeostasis is altered in patients with recent onset of schizophrenia. As a possible marker of metabolic changes that might link to altered neurotransmission, we used proton magnetic resonance spectroscopy to estimate brain temperature, and we evaluated its relationship to a relevant metabolite, glutamate, within this study population. METHODS Using proton magnetic resonance spectroscopy at 7T, 20 patients with recent onset (≤24 months after first psychotic symptoms) of schizophrenia and 20 healthy control subjects were studied. We measured levels of N-acetylaspartate and glutamate and estimated brain temperature in a noninvasive manner. RESULTS Healthy control subjects showed a significant negative correlation between glutamate and brain temperature in the anterior cingulate cortex. In contrast, the physiological correlation between glutamate and brain temperature was lost in patients with recent onset of schizophrenia. CONCLUSIONS This study supports the hypothesized disrupted relationship between brain metabolism and neurotransmission in patients with recent onset of schizophrenia. The findings include mechanistic implications that are to be followed up in both preclinical and clinical studies.
Collapse
Affiliation(s)
- Sotirios Posporelis
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland; South London and Maudsley National Health Service Foundation Trust, London, United Kingdom
| | - Jennifer M Coughlin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland; Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Anouk Marsman
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Subechhya Pradhan
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Teppei Tanaka
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Hongxing Wang
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Mark Varvaris
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Rebecca Ward
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Cecilia Higgs
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Jamie A Edwards
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Candice N Ford
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Pearl K Kim
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Ashley M Lloyd
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Richard A E Edden
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - David J Schretlen
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Nicola G Cascella
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Peter B Barker
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Akira Sawa
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland.
| |
Collapse
|
19
|
Mohamed M, Barker PB, Skolasky RL, Sacktor N. 7T Brain MRS in HIV Infection: Correlation with Cognitive Impairment and Performance on Neuropsychological Tests. AJNR Am J Neuroradiol 2018; 39:704-712. [PMID: 29449278 DOI: 10.3174/ajnr.a5547] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 12/01/2017] [Indexed: 01/13/2023]
Abstract
BACKGROUND AND PURPOSE Validated neuroimaging markers of HIV-associated neurocognitive disorder in patients on antiretroviral therapy are urgently needed for clinical trials. The purpose of this study was to explore the relationship between cognitive impairment and brain metabolism in older subjects with HIV infection. It was hypothesized that MR spectroscopy measurements related to neuronal health and function (particularly N-acetylaspartate and glutamate) would be lower in HIV-positive subjects with worse cognitive performance. MATERIALS AND METHODS Forty-five HIV-positive patients (mean age, 58.9 ± 5.3 years; 33 men) underwent detailed neuropsychological testing and brain MR spectroscopy at 7T. Twenty-four subjects were classified as having asymptomatic cognitive impairment, and 21 were classified as having symptomatic cognitive impairment. Single-voxel proton MR spectra were acquired from 5 brain regions and quantified using LCModel software. Brain metabolites and neuropsychological test results were compared using nonparametric statistics and Pearson correlation coefficients. RESULTS Differences in brain metabolites were found between symptomatic and asymptomatic subjects, with the main findings being lower measures of N-acetylaspartate in the frontal white matter, posterior cingulate cortex, and precuneus. In the precuneus, glutamate was also lower in the symptomatic group. In the frontal white matter, precuneus, and posterior cingulate cortex, NAA and glutamate measurements showed significant positive correlation with better performance on neuropsychological tests. CONCLUSIONS Compared with asymptomatic subjects, symptomatic HIV-positive subjects had lower levels of NAA and glutamate, most notably in the frontal white matter, which also correlated with performance on neuropsychological tests. High-field MR spectroscopy offers insight into the pathophysiology associated with cognitive impairment in HIV and may be useful as a quantitative outcome measure in future treatment trials.
Collapse
Affiliation(s)
- M Mohamed
- From the Russell H. Morgan Department of Radiology and Radiological Science (M.M., P.B.B.)
| | - P B Barker
- From the Russell H. Morgan Department of Radiology and Radiological Science (M.M., P.B.B.).,Psychiatry and Behavioral Sciences (P.B.B.), Johns Hopkins University School of Medicine, Baltimore, Maryland.,F.M. Kirby Center for Functional Brain Imaging (P.B.B.), Kennedy Krieger Institute, Baltimore, Maryland
| | - R L Skolasky
- Departments of Neurology (R.L.S., N.S.).,Orthopedic Surgery (R.L.S.)
| | - N Sacktor
- Departments of Neurology (R.L.S., N.S.)
| |
Collapse
|
20
|
Dobberthien BJ, Tessier AG, Yahya A. Improved resolution of glutamate, glutamine and γ-aminobutyric acid with optimized point-resolved spectroscopy sequence timings for their simultaneous quantification at 9.4 T. NMR IN BIOMEDICINE 2018; 31:e3851. [PMID: 29105187 DOI: 10.1002/nbm.3851] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 09/15/2017] [Accepted: 09/25/2017] [Indexed: 06/07/2023]
Abstract
Glutamine (Gln), glutamate (Glu) and γ-aminobutyric acid (GABA) are relevant brain metabolites that can be measured with magnetic resonance spectroscopy (MRS). This work optimizes the point-resolved spectroscopy (PRESS) sequence echo times, TE1 and TE2 , for improved simultaneous quantification of the three metabolites at 9.4 T. Quantification was based on the proton resonances of Gln, Glu and GABA at ≈2.45, ≈2.35 and ≈2.28 ppm, respectively. Glu exhibits overlap with both Gln and GABA; in addition, the Gln peak is contaminated by signal from the strongly coupled protons of N-acetylaspartate (NAA), which resonate at about 2.49 ppm. J-coupling evolution of the protons was characterized numerically and verified experimentally. A {TE1 , TE2 } combination of {106 ms, 16 ms} minimized the NAA signal in the Gln spectral region, whilst retaining Gln, Glu and GABA peaks. The efficacy of the technique was verified on phantom solutions and on rat brain in vivo. LCModel was employed to analyze the in vivo spectra. The average T2 -corrected Gln, Glu and GABA concentrations were found to be 3.39, 11.43 and 2.20 mM, respectively, assuming a total creatine concentration of 8.5 mM. LCModel Cramér-Rao lower bounds (CRLBs) for Gln, Glu and GABA were in the ranges 14-17%, 4-6% and 16-19%, respectively. The optimal TE resulted in concentrations for Gln and GABA that agreed more closely with literature concentrations compared with concentrations obtained from short-TE spectra acquired with a {TE1 , TE2 } combination of {12 ms, 9 ms}. LCModel estimations were also evaluated with short-TE PRESS and with the optimized long TE of {106 ms, 16 ms}, using phantom solutions of known metabolite concentrations. It was shown that concentrations estimated with LCModel can be inaccurate when combined with short-TE PRESS, where there is peak overlap, even when low (<20%) CRLBs are reported.
Collapse
Affiliation(s)
| | - Anthony G Tessier
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, Canada
| | - Atiyah Yahya
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, Canada
| |
Collapse
|
21
|
Comparing GABA-dependent physiological measures of inhibition with proton magnetic resonance spectroscopy measurement of GABA using ultra-high-field MRI. Neuroimage 2017; 152:360-370. [PMID: 28284797 PMCID: PMC5440178 DOI: 10.1016/j.neuroimage.2017.03.011] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 03/04/2017] [Accepted: 03/06/2017] [Indexed: 12/16/2022] Open
Abstract
Imbalances in glutamatergic (excitatory) and GABA (inhibitory) signalling within key brain networks are thought to underlie many brain and mental health disorders, and for this reason there is considerable interest in investigating how individual variability in localised concentrations of these molecules relate to brain disorders. Magnetic resonance spectroscopy (MRS) provides a reliable means of measuring, in vivo, concentrations of neurometabolites such as GABA, glutamate and glutamine that can be correlated with brain function and dysfunction. However, an issue of much debate is whether the GABA observed and measured using MRS represents the entire pool of GABA available for measurement (i.e., metabolic, intracellular, and extracellular) or is instead limited to only some portion of it. GABA function can also be investigated indirectly in humans through the use of non-invasive transcranial magnetic stimulation (TMS) techniques that can be used to measure cortical excitability and GABA-mediated physiological inhibition. To investigate this issue further we collected in a single session both types of measurement, i.e., TMS measures of cortical excitability and physiological inhibition and ultra-high-field (7 T) MRS measures of GABA, glutamate and glutamine, from the left sensorimotor cortex of the same group of right-handed individuals. We found that TMS and MRS measures were largely uncorrelated with one another, save for the plateau of the TMS IO curve that was negatively correlated with MRS-Glutamate (Glu) and intra-cortical facilitation (10ms ISI) that was positively associated with MRS-Glutamate concentration. These findings are consistent with the view that the GABA concentrations measured using the MRS largely represent pools of GABA that are linked to tonic rather than phasic inhibition and thus contribute to the inhibitory tone of a brain area rather than GABAergic synaptic transmission.
Collapse
|
22
|
Brix MK, Ersland L, Hugdahl K, Dwyer GE, Grüner R, Noeske R, Beyer MK, Craven AR. Within- and between-session reproducibility of GABA measurements with MR spectroscopy. J Magn Reson Imaging 2017; 46:421-430. [DOI: 10.1002/jmri.25588] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 11/28/2016] [Indexed: 12/28/2022] Open
Affiliation(s)
- Maiken K. Brix
- Department of Radiology; Haukeland University Hospital; Bergen Norway
- Department of Clinical Medicine (K1); University of Bergen; Bergen Norway
| | - Lars Ersland
- Department of Clinical Engineering; Haukeland University Hospital; Bergen Norway
- NORMENT - Norwegian Center for Mental Disorders Research; University of Bergen; Bergen Norway
| | - Kenneth Hugdahl
- Department of Radiology; Haukeland University Hospital; Bergen Norway
- NORMENT - Norwegian Center for Mental Disorders Research; University of Bergen; Bergen Norway
- Department of Biological and Medical Psychology; University of Bergen; Bergen Norway
- Division of Psychiatry; Haukeland University Hospital; Bergen Norway
| | - Gerard E. Dwyer
- Department of Biological and Medical Psychology; University of Bergen; Bergen Norway
| | - Renate Grüner
- Department of Radiology; Haukeland University Hospital; Bergen Norway
- NORMENT - Norwegian Center for Mental Disorders Research; University of Bergen; Bergen Norway
- Department of Physics and Technology; University of Bergen; Bergen Norway
| | - Ralph Noeske
- MR Applications and Workflow Development, GE Healthcare; Berlin Germany
| | - Mona K. Beyer
- Department of Radiology and Nuclear Medicine; Oslo University Hospital; Oslo Norway
- Department of Life Sciences and Health, Faculty of Health Sciences; Oslo and Akershus University College of Applied Sciences; Oslo Norway
| | - Alexander R. Craven
- NORMENT - Norwegian Center for Mental Disorders Research; University of Bergen; Bergen Norway
- Department of Biological and Medical Psychology; University of Bergen; Bergen Norway
| |
Collapse
|
23
|
Chen M, Liao C, Chen S, Ding Q, Zhu D, Liu H, Yan X, Zhong J. Uncertainty assessment of gamma-aminobutyric acid concentration of different brain regions in individual and group using residual bootstrap analysis. Med Biol Eng Comput 2016; 55:1051-1059. [PMID: 27696130 DOI: 10.1007/s11517-016-1579-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Accepted: 09/26/2016] [Indexed: 12/24/2022]
Abstract
The aim of this work is to quantify individual and regional differences in the relative concentration of gamma-aminobutyric acid (GABA) in human brain with in vivo magnetic resonance spectroscopy. Spectral editing Mescher-Garwood point resolved spectroscopy (MEGA-PRESS) sequence and GABA analysis toolkit (Gannet) were used to detect and quantify GABA in anterior cingulate cortex (ACC) and occipital cortex (OCC) of healthy volunteers. Residual bootstrap, a model-based statistical analysis technique, was applied to resample the fitting residuals of GABA from the Gaussian fitting model (referred to as GABA+ thereafter) in both individual and group data of ACC and OCC. The inter-subject coefficient of variation (CV) of GABA+ in OCC (20.66 %) and ACC (12.55 %) with residual bootstrap was lower than that of a standard Gaussian model analysis (21.58 % and 16.73 % for OCC and ACC, respectively). The intra-subject uncertainty and CV of OCC were lower than that of ACC in both analyses. The residual bootstrap analysis thus provides a more robust uncertainty estimation of individual and group GABA+ detection in different brain regions, which may be useful in our understanding of GABA biochemistry in brain and its use for the diagnosis of related neuropsychiatric diseases.
Collapse
Affiliation(s)
- Meng Chen
- Center for Brain Imaging Science and Technology, Department of Biomedical Engineering, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Congyu Liao
- Center for Brain Imaging Science and Technology, Department of Biomedical Engineering, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China.
| | - Song Chen
- Center for Brain Imaging Science and Technology, Department of Biomedical Engineering, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Qiuping Ding
- Center for Brain Imaging Science and Technology, Department of Biomedical Engineering, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Darong Zhu
- Department of Radiology, Hangzhou First People's Hospital, Hangzhou, Zhejiang, China
| | - Hui Liu
- MR Collaboration NE Asia, Siemens Healthcare, Shanghai, China
| | - Xu Yan
- MR Collaboration NE Asia, Siemens Healthcare, Shanghai, China
| | - Jianhui Zhong
- Center for Brain Imaging Science and Technology, Department of Biomedical Engineering, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Imaging Sciences, University of Rochester, Rochester, NY, USA.,Center for Innovative and Collaborative Detection and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, Zhejiang, China
| |
Collapse
|
24
|
Terpstra M, Cheong I, Lyu T, Deelchand DK, Emir UE, Bednařík P, Eberly LE, Öz G. Test-retest reproducibility of neurochemical profiles with short-echo, single-voxel MR spectroscopy at 3T and 7T. Magn Reson Med 2016; 76:1083-91. [PMID: 26502373 PMCID: PMC4846596 DOI: 10.1002/mrm.26022] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 09/23/2015] [Accepted: 09/28/2015] [Indexed: 02/03/2023]
Abstract
PURPOSE To determine the test-retest reproducibility of neurochemical concentrations obtained with a highly optimized, short-echo, single-voxel proton MR spectroscopy (MRS) pulse sequence at 3T and 7T using state-of-the-art hardware. METHODS A semi-LASER sequence (echo time = 26-28 ms) was used to acquire spectra from the posterior cingulate and cerebellum at 3T and 7T from six healthy volunteers who were scanned four times weekly on both scanners. Spectra were quantified with LCModel. RESULTS More neurochemicals were quantified with mean Cramér-Rao lower bounds (CRLBs) ≤20% at 7T than at 3T despite comparable frequency-domain signal-to-noise ratio. Whereas CRLBs were lower at 7T (P < 0.05), between-session coefficients of variance (CVs) were comparable at the two fields with 64 transients. Five metabolites were quantified with between-session CVs ≤5% at both fields. Analysis of subspectra showed that a minimum achievable CV was reached with a lower number of transients at 7T for multiple metabolites and that between-session CVs were lower at 7T than at 3T with fewer than 64 transients. CONCLUSION State-of-the-art MRS methodology allows excellent reproducibility for many metabolites with 5-min data averaging on clinical 3T hardware. Sensitivity and resolution advantages at 7T are important for weakly represented metabolites, short acquisitions, and small volumes of interest. Magn Reson Med 76:1083-1091, 2016. © 2015 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Melissa Terpstra
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ian Cheong
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Tianmeng Lyu
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota, USA
| | - Dinesh K Deelchand
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Uzay E Emir
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Petr Bednařík
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
- Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
- Multimodal and Functional Neuroimaging Research Group, Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Lynn E Eberly
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota, USA
| | - Gülin Öz
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA.
| |
Collapse
|
25
|
Nanga RPR, Hariharan H, Reddy R. Fully automated macromolecule suppressed single voxel glutamate spectroscopy (FAMOUS SVGS). J Transl Med 2016; 14:220. [PMID: 27456699 PMCID: PMC4960747 DOI: 10.1186/s12967-016-0970-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/11/2016] [Indexed: 11/10/2022] Open
Abstract
PURPOSE The aim of the study was to develop and validate a new localized (1)H MRS pulse sequence and automated post-processing software for the quantification of brain Glutamate (Glu) in clinical conditions at 7.0T in order to get reliable and reproducible results for acute intervention studies. METHODS Here we describe a new localized proton MRS method "Fully Automated MacrOmolecUle Suppressed Single Voxel Glutamate Spectroscopy (FAMOUS SVGS)" for measuring Glu. FAMOUS SVGS method consists of a new pulse sequence with optimized switchable water, metabolites and outer volume suppression modules, as well as a frequency selective inversion pulse and automated post-processing of the five spectra obtained. FAMOUS SVGS method was first validated with glutamate phantoms and then validated with test-retest repeatability studies in the occipital cortex of five normal volunteers at 7.0T. RESULTS Glutamate concentrations estimated from phantoms with FAMOUS SVGS method correlated well with actual concentrations. Test-retest repeatability studies in human brain in vivo yielded less than 0.3 mM intra-subject variations in Glu concentrations. CONCLUSIONS FAMOUS SVGS method enables Glu quantification in vivo at 7.0T with test-retest variability of less than 0.3 mM. We expect that we can reliably measure ≥0.5 mM change in glutamate due to any acute intervention.
Collapse
Affiliation(s)
- Ravi Prakash Reddy Nanga
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, B1 Stellar-Chance Laboratories, 422 Curie Boulevard, Philadelphia, PA, 19104-6100, USA.
| | - Hari Hariharan
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, B1 Stellar-Chance Laboratories, 422 Curie Boulevard, Philadelphia, PA, 19104-6100, USA
| | - Ravinder Reddy
- Department of Radiology, Center for Magnetic Resonance and Optical Imaging, University of Pennsylvania, B1 Stellar-Chance Laboratories, 422 Curie Boulevard, Philadelphia, PA, 19104-6100, USA
| |
Collapse
|
26
|
Prinsen H, de Graaf RA, Mason GF, Pelletier D, Juchem C. Reproducibility measurement of glutathione, GABA, and glutamate: Towards in vivo neurochemical profiling of multiple sclerosis with MR spectroscopy at 7T. J Magn Reson Imaging 2016; 45:187-198. [PMID: 27351712 DOI: 10.1002/jmri.25356] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/06/2016] [Indexed: 12/22/2022] Open
Abstract
PURPOSE To determine the reproducibility of a comprehensive single-session measurement of glutathione (GSH), γ-aminobutyric acid (GABA), glutamate, and other biochemicals implicated in the pathophysiology of multiple sclerosis (MS) in the human brain with 1 H magnetic resonance spectroscopy (MRS). MATERIALS AND METHODS Five healthy subjects were studied twice in separate 1-hour sessions at 7T. One MS patient was also scanned once. GSH and GABA were measured with J-difference editing using a semilocalized by adiabatic selective refocusing sequence (semi-LASER, TE = 72 msec). A stimulated echo acquisition mode sequence (STEAM, TE = 10 msec) was used to detect glutamate along with the overall biochemical profile. Spectra were quantified with LCModel. Quantification accuracy was assessed through Cramer-Rao lower bounds (CRLB). Reproducibility of the metabolite quantification was tested using coefficients of variation (CoV). RESULTS CRLB were ≤7% for GSH, GABA, and glutamate and average CoV of 7.8 ± 3.2%, 9.5 ± 7.0%, and 3.2 ± 1.7% were achieved, respectively. The average test/retest concentration differences at this measurement reproducibility and quantification accuracy were smaller for GABA and glutamate than intersubject variations in metabolite content with CoV ratios of 0.6 and 0.8, respectively. As proof of principle, GSH, GABA, and glutamate were also detected in an MS patient. CONCLUSION GSH, GABA, glutamate, and other metabolites relevant in MS can be quantified at 7T with high accuracy and reproducibility in a single 1-hour session. This methodology might serve as a clinical research tool to investigate biochemical markers associated with MS. LEVEL OF EVIDENCE 2 J. Magn. Reson. Imaging 2017;45:187-198.
Collapse
Affiliation(s)
- Hetty Prinsen
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, USA
| | - Robin A de Graaf
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, USA.,Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
| | - Graeme F Mason
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, USA.,Department of Psychiatry, Yale University, New Haven, Connecticut, USA
| | - Daniel Pelletier
- Department of Neurology, Yale University, New Haven, Connecticut, USA
| | - Christoph Juchem
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, USA.,Department of Neurology, Yale University, New Haven, Connecticut, USA
| |
Collapse
|
27
|
Greenhouse I, Noah S, Maddock RJ, Ivry RB. Individual differences in GABA content are reliable but are not uniform across the human cortex. Neuroimage 2016; 139:1-7. [PMID: 27288552 DOI: 10.1016/j.neuroimage.2016.06.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 05/01/2016] [Accepted: 06/06/2016] [Indexed: 11/15/2022] Open
Abstract
1H magnetic resonance spectroscopy (MRS) provides a powerful tool to measure gamma-aminobutyric acid (GABA), the principle inhibitory neurotransmitter in the human brain. We asked whether individual differences in MRS estimates of GABA are uniform across the cortex or vary between regions. In two sessions, resting GABA concentrations in the lateral prefrontal, sensorimotor, dorsal premotor, and occipital cortices were measured in twenty-eight healthy individuals. GABA estimates within each region were stable across weeks, with low coefficients of variation. Despite this stability, the GABA estimates were not correlated between regions. In contrast, the percentage of brain tissue per volume, a control measure, was correlated between the three anterior regions. These results provide an interesting dissociation between an anatomical measure of individual differences and a neurochemical measure. The different patterns of anatomy and GABA concentrations have implications for understanding regional variation in the molecular topography of the brain in health and disease.
Collapse
Affiliation(s)
- Ian Greenhouse
- University of California, Berkeley, Berkeley, CA, United States.
| | - Sean Noah
- University of California, Berkeley, Berkeley, CA, United States
| | | | - Richard B Ivry
- University of California, Berkeley, Berkeley, CA, United States
| |
Collapse
|
28
|
Proton magnetic resonance spectroscopy as a diagnostic biomarker in mild cognitive impairment following stroke in acute phase. Neuroreport 2016; 27:559-63. [PMID: 26981713 DOI: 10.1097/wnr.0000000000000555] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
To investigate proton magnetic resonance spectroscopy (HMRS) as a diagnostic biomarker to identify mild cognitive impairment (MCI) following stroke in the acute phase. A total of 72 stroke patients were recruited in the acute phase of stroke from the Department of Neurology, including 36 stroke patients with MCI and 36 stroke patients without MCI. All patients underwent brain MRI/MRS examination on a 3.0 T scanner and a neuropsychological test in the acute phase of stroke. Single-voxel HMRS was performed to obtain hippocampal metabolism intensities and brain infarcts were assessed on MRI. Group difference in metabolite ratios was analyzed using a T-test. Spearman rank correlation was used to study the correlation between metabolite ratios and Montreal Cognitive Assessment scores. The hippocampal n-acetylaspartate/creatine (NAA/Cr) ratio was found to be significantly lower in stroke patients with MCI compared with stroke patients without MCI (P<0.02). However, we found no differences in the metabolite ratios between hippocampus ipsilateral to infarctions and the contralateral side (P>0.05) in stroke patients with MCI. Furthermore, a correlation was found between hippocampal NAA/Cr ratios and Montreal Cognitive Assessment scores in stroke patients with MCI (P<0.01). HMRS could be a biomarker to identify MCI following stroke in the acute phase by capturing neurodegenerative changes.
Collapse
|
29
|
Schür RR, Draisma LWR, Wijnen JP, Boks MP, Koevoets MGJC, Joëls M, Klomp DW, Kahn RS, Vinkers CH. Brain GABA levels across psychiatric disorders: A systematic literature review and meta-analysis of (1) H-MRS studies. Hum Brain Mapp 2016; 37:3337-52. [PMID: 27145016 DOI: 10.1002/hbm.23244] [Citation(s) in RCA: 209] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 12/12/2022] Open
Abstract
The inhibitory gamma-aminobutyric acid (GABA) system is involved in the etiology of most psychiatric disorders, including schizophrenia, autism spectrum disorder (ASD) and major depressive disorder (MDD). It is therefore not surprising that proton magnetic resonance spectroscopy ((1) H-MRS) is increasingly used to investigate in vivo brain GABA levels. However, integration of the evidence for altered in vivo GABA levels across psychiatric disorders is lacking. We therefore systematically searched the clinical (1) H-MRS literature and performed a meta-analysis. A total of 40 studies (N = 1,591) in seven different psychiatric disorders were included in the meta-analysis: MDD (N = 437), schizophrenia (N = 517), ASD (N = 150), bipolar disorder (N = 129), panic disorder (N = 81), posttraumatic stress disorder (PTSD) (N = 104), and attention deficit/hyperactivity disorder (ADHD) (N = 173). Brain GABA levels were lower in ASD (standardized mean difference [SMD] = -0.74, P = 0.001) and in depressed MDD patients (SMD = -0.52, P = 0.005), but not in remitted MDD patients (SMD = -0.24, P = 0.310) compared with controls. In schizophrenia this finding did not reach statistical significance (SMD = -0.23, P = 0.089). No significant differences in GABA levels were found in bipolar disorder, panic disorder, PTSD, and ADHD compared with controls. In conclusion, this meta-analysis provided evidence for lower brain GABA levels in ASD and in depressed (but not remitted) MDD patients compared with healthy controls. Findings in schizophrenia were more equivocal. Even though future (1) H-MRS studies could greatly benefit from a longitudinal design and consensus on the preferred analytical approach, it is apparent that (1) H-MRS studies have great potential in advancing our understanding of the role of the GABA system in the pathogenesis of psychiatric disorders. Hum Brain Mapp 37:3337-3352, 2016. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Remmelt R Schür
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
| | - Luc W R Draisma
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
| | - Jannie P Wijnen
- Department of Radiology, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
| | - Marco P Boks
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
| | - Martijn G J C Koevoets
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
| | - Marian Joëls
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
| | - Dennis W Klomp
- Department of Radiology, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
| | - René S Kahn
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
| | - Christiaan H Vinkers
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
| |
Collapse
|
30
|
Improved Cardiac Proton Magnetic Resonance Spectroscopy at 3 T Using High Permittivity Pads. Invest Radiol 2016; 51:134-8. [DOI: 10.1097/rli.0000000000000214] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
31
|
Lally N, An L, Banerjee D, Niciu MJ, Luckenbaugh DA, Richards EM, Roiser JP, Shen J, Zarate CA, Nugent AC. Reliability of 7T (1) H-MRS measured human prefrontal cortex glutamate, glutamine, and glutathione signals using an adapted echo time optimized PRESS sequence: A between- and within-sessions investigation. J Magn Reson Imaging 2016; 43:88-98. [PMID: 26059603 PMCID: PMC4671833 DOI: 10.1002/jmri.24970] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 05/22/2015] [Indexed: 12/12/2022] Open
Abstract
PURPOSE To ascertain the mechanisms of neuropsychiatric illnesses and their treatment, accurate and reliable imaging techniques are required; proton magnetic resonance spectroscopy ((1) H-MRS) can noninvasively measure glutamatergic function. Evidence suggests that aberrant glutamatergic signaling plays a role in numerous psychopathologies. Until recently, overlapping glutamatergic signals (glutamate, glutamine, and glutathione) could not easily be separated. However, the advent of novel pulse sequences and higher field magnetic resonance imaging (MRI) allows more precise resolution of overlapping glutamatergic signals, although the question of signal reliability remains undetermined. MATERIALS AND METHODS At 7T MR, we acquired (1) H-MRS data from the medial pregenual anterior cingulate cortex of healthy volunteers (n = 26) twice on two separate days. An adapted echo time optimized point-resolved spectroscopy sequence, modified with the addition of a J-suppression pulse to attenuate N-acetyl-aspartate multiplet signals at 2.49 ppm, was used to excite and acquire the spectra. In-house software was used to model glutamate, glutamine, and glutathione, among other metabolites, referenced to creatine. Intraclass correlation coefficients (ICCs) were computed for within- and between-session measurements. RESULTS Within-session measurements of glutamate, glutamine, and glutathione were on average reliable (ICCs ≥0.7). As anticipated, ICCs for between-session values of glutamate, glutamine, and glutathione were slightly lower but nevertheless reliable (ICC >0.62). A negative correlation was observed between glutathione concentration and age (r(24) = -0.37; P < 0.05), and a gender effect was noted on glutamine and glutathione. CONCLUSION The adapted sequence provides good reliability to measure glutamate, glutamine, and glutathione signals.
Collapse
Affiliation(s)
- Níall Lally
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
- Institute of Cognitive Neuroscience, University College London, Alexandra House, 17 Queen Square, London, WC1N 3AR, UK
| | - Li An
- Magnetic Resonance Spectroscopy Core Facility, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| | - Dipavo Banerjee
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| | - Mark J. Niciu
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| | - David A. Luckenbaugh
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| | - Erica M. Richards
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| | - Jonathan P Roiser
- Institute of Cognitive Neuroscience, University College London, Alexandra House, 17 Queen Square, London, WC1N 3AR, UK
| | - Jun Shen
- Magnetic Resonance Spectroscopy Core Facility, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| | - Carlos A. Zarate
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| | - Allison C. Nugent
- Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| |
Collapse
|
32
|
Long Z, Dyke JP, Ma R, Huang CC, Louis ED, Dydak U. Reproducibility and effect of tissue composition on cerebellar γ-aminobutyric acid (GABA) MRS in an elderly population. NMR IN BIOMEDICINE 2015; 28:1315-23. [PMID: 26314380 PMCID: PMC4594865 DOI: 10.1002/nbm.3381] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 07/22/2015] [Accepted: 07/24/2015] [Indexed: 05/06/2023]
Abstract
MRS provides a valuable tool for the non-invasive detection of brain γ-aminobutyric acid (GABA) in vivo. GABAergic dysfunction has been observed in the aging cerebellum. The study of cerebellar GABA changes is of considerable interest in understanding certain age-related motor disorders. However, little is known about the reproducibility of GABA MRS in an aged population. Therefore, this study aimed to explore the feasibility and reproducibility of GABA MRS in the aged cerebellum at 3.0 T and to examine the effect of differing tissue composition on GABA measurements. MRI and (1)H MRS examinations were performed on 10 healthy elderly volunteers (mean age, 75.2 ± 6.5 years) using a 3.0-T Siemens Tim Trio scanner. Among them, five subjects were scanned twice to assess the short-term reproducibility. The MEGA-PRESS (Mescher-Garwood point-resolved spectroscopy) J-editing sequence was used for GABA detection in two volumes of interest (VOIs) in the left and right cerebellar dentate. MRS data processing and quantification were performed with LCModel 6.3-0L using two separate basis sets, generated from density matrix simulations using published values for chemical shifts and J couplings. Raw metabolite levels from LCModel outputs were corrected for cerebrospinal fluid contamination and relaxation. GABA-edited spectra yielded robust and stable GABA measurements with averaged intra-individual coefficients of variation for corrected GABA+ between 4.0 ± 2.8% and 13.4 ± 6.3%, and inter-individual coefficients of variation between 12.6% and 24.2%. In addition, there was a significant correlation between GABA+ obtained with the two LCModel basis sets. Overall, our results demonstrated the feasibility and reproducibility of cerebellar GABA-edited MRS at 3.0 T in an elderly population. This information might be helpful for studies using this technique to study GABA changes in normal or diseased aging brain, e.g. for power calculations and the interpretation of longitudinal observations.
Collapse
Affiliation(s)
- Zaiyang Long
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Jonathan P. Dyke
- Department of Radiology, Weill Cornell Medical College, New York, NY, USA
| | - Ruoyun Ma
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Chaorui C. Huang
- Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY, USA
| | - Elan D. Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
- Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Ulrike Dydak
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
- Correspondence to: U. Dydak, School of Health Sciences, Purdue University, West Lafayette, IN, 47907, USA.
| |
Collapse
|
33
|
The separation of Gln and Glu in STEAM: a comparison study using short and long TEs/TMs at 3 and 7 T. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2015; 28:395-405. [DOI: 10.1007/s10334-014-0479-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 12/12/2014] [Accepted: 12/15/2014] [Indexed: 10/24/2022]
|
34
|
Reproducibility and absolute quantification of muscle glycogen in patients with glycogen storage disease by 13C NMR spectroscopy at 7 Tesla. PLoS One 2014; 9:e108706. [PMID: 25296331 PMCID: PMC4189928 DOI: 10.1371/journal.pone.0108706] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 09/01/2014] [Indexed: 11/19/2022] Open
Abstract
Carbon-13 magnetic resonance spectroscopy (13C MRS) offers a noninvasive method to assess glycogen levels in skeletal muscle and to identify excess glycogen accumulation in patients with glycogen storage disease (GSD). Despite the clinical potential of the method, it is currently not widely used for diagnosis or for follow-up of treatment. While it is possible to perform acceptable 13C MRS at lower fields, the low natural abundance of 13C and the inherently low signal-to-noise ratio of 13C MRS makes it desirable to utilize the advantage of increased signal strength offered by ultra-high fields for more accurate measurements. Concomitant with this advantage, however, ultra-high fields present unique technical challenges that need to be addressed when studying glycogen. In particular, the question of measurement reproducibility needs to be answered so as to give investigators insight into meaningful inter-subject glycogen differences. We measured muscle glycogen levels in vivo in the calf muscle in three patients with McArdle disease (MD), one patient with phosphofructokinase deficiency (PFKD) and four healthy controls by performing 13C MRS at 7T. Absolute quantification of the MRS signal was achieved by using a reference phantom with known concentration of metabolites. Muscle glycogen concentration was increased in GSD patients (31.5±2.9 g/kg w. w.) compared with controls (12.4±2.2 g/kg w. w.). In three GSD patients glycogen was also determined biochemically in muscle homogenates from needle biopsies and showed a similar 2.5-fold increase in muscle glycogen concentration in GSD patients compared with controls. Repeated inter-subject glycogen measurements yield a coefficient of variability of 5.18%, while repeated phantom measurements yield a lower 3.2% system variability. We conclude that noninvasive ultra-high field 13C MRS provides a valuable, highly reproducible tool for quantitative assessment of glycogen levels in health and disease.
Collapse
|
35
|
Penner J, Bartha R. Semi-LASER 1 H MR spectroscopy at 7 Tesla in human brain: Metabolite quantification incorporating subject-specific macromolecule removal. Magn Reson Med 2014; 74:4-12. [PMID: 25081993 DOI: 10.1002/mrm.25380] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 06/04/2014] [Accepted: 06/30/2014] [Indexed: 11/08/2022]
Abstract
PURPOSE To develop an in vivo 1 H short-echo-time semi-LASER spectroscopy protocol at 7 Tesla (T) incorporating subject-specific macromolecule removal. METHODS T1 constants of the major metabolites were measured with little macromolecule contribution in seven healthy volunteers and used to optimize double inversion metabolite nulling. Spectra were acquired from parietal-occipital cortex of five healthy volunteers. Metabolite-nulled macromolecule spectra were subtracted from the metabolite spectra before fitting in the time domain with prior-knowledge templates. Absolute metabolite concentrations were determined by referencing to the water signal, following partial volume and relaxation corrections. RESULTS The average signal to noise ratio, N-acetylaspartate peak height divided by the baseline noise standard deviation, was 48 ± 6. T1 constants for N-acetylaspartate, glutamate, creatine, and choline were 1.71 ± 0.15 s, 1.68 ± 0.19 s, 1.63 ± 0.10 s, and 1.41 ± 0.09 s, respectively. The optimal double inversion times for metabolite suppression were TI1 = 2.09 s and TI2 = 0.52 s. The coefficient of variation was less than 10% for N-acetylaspartate, creatine, choline, and myo-inositol, and less than 20% for glutamate and glutamine. CONCLUSION Short echo-time 1 H semi-LASER spectroscopy at 7T incorporating subject-specific macromolecule removal yielded reproducible brain metabolite concentrations ideal for applications in disease conditions where macromolecule contributions may deviate from the norm. Magn Reson Med 74:4-12, 2015. © 2014 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Jacob Penner
- Centre for Functional and Metabolic Mapping (CFMM), Robarts Research Institute, University of Western Ontario, London, Canada.,Department of Medical Biophysics, University of Western Ontario, London, Canada
| | - Robert Bartha
- Centre for Functional and Metabolic Mapping (CFMM), Robarts Research Institute, University of Western Ontario, London, Canada.,Department of Medical Biophysics, University of Western Ontario, London, Canada
| |
Collapse
|
36
|
Near J, Ho YCL, Sandberg K, Kumaragamage C, Blicher JU. Long-term reproducibility of GABA magnetic resonance spectroscopy. Neuroimage 2014; 99:191-6. [PMID: 24875142 DOI: 10.1016/j.neuroimage.2014.05.059] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 04/14/2014] [Accepted: 05/20/2014] [Indexed: 12/29/2022] Open
Abstract
Recent findings suggest that cortical gamma aminobutyric acid (GABA) levels may provide a surrogate marker for a number of psychiatric and neurological conditions, as well as behavioural traits. However, the natural variability of GABA levels in the human brain over long periods of time (>8 days) has not yet been studied. The purpose of this work was to investigate the long-term variability of GABA concentrations in the human occipital cortex. Nineteen healthy male participants were recruited and underwent two sessions of magnetic resonance spectroscopy (MRS) to determine occipital GABA levels with an average between-session interval of 7 months. We assessed between-session variability, as well as the correlation between session 1 and session 2 GABA measurements. The mean coefficient of variation between sessions was 4.3% (bootstrap 95% confidence interval: 2.5, 6.4), which is comparable to reported GABA variability measurements over much shorter time intervals (<8 days). A significant positive correlation was observed between session 1 and session 2 GABA measurements (r=0.53, p=0.014), and the intra-class correlation coefficient was calculated to be 0.52 which was also statistically significant (p=0.012). These findings establish experimentally that GABA concentrations in the occipital cortex, as measured by MRS, are relatively stable over periods as long as 7 months. The findings have significant implications for the internal validity of longitudinal studies of GABA levels in the human brain, and they lend foundational support to studies relating GABA levels to behavioural traits in healthy individuals.
Collapse
Affiliation(s)
- Jamie Near
- Douglas Mental Health University Institute and Department of Psychiatry, McGill University, 6875 LaSalle Blvd, Montreal H4H 1R3, Canada; Department of Biomedical Engineering, McGill University, Room 316, Duff Medical Building, 3775 Rue University, Montreal H3A 2B4, Canada.
| | - Yi-Ching Lynn Ho
- Center of Functionally Integrative Neuroscience (CFIN), Aarhus University, Nørrebrogade 44, Building 10G, 5th Floor, 8000 Aarhus C, Denmark
| | - Kristian Sandberg
- Cognitive Neurosciences Research Unit (CNRU), Hammel Neurorehabilitation Centre and University Research Clinic, Aarhus University, Nørrebrogade 44, Building 10G, 8000 Aarhus C, Denmark; UCL Institute of Cognitive Neuroscience, University College London, Alexandra House, 17 Queen Square, London WC1N 3AR, UK
| | - Chathura Kumaragamage
- Department of Biomedical Engineering, McGill University, Room 316, Duff Medical Building, 3775 Rue University, Montreal H3A 2B4, Canada
| | - Jakob Udby Blicher
- Center of Functionally Integrative Neuroscience (CFIN), Aarhus University, Nørrebrogade 44, Building 10G, 5th Floor, 8000 Aarhus C, Denmark; Hammel Neurorehabilitation and Research Centre, Aarhus University Hospital, Voldbyvej 15, 8450 Hammel, Denmark
| |
Collapse
|
37
|
Lin Y, Yao J, Chen Y, Pang L, Li H, Cao Z, You K, Dai H, Wu R. Hippocampal neurochemical changes in senescent mice induced with chronic injection of D-galactose and NaNO₂: an in vitro high-resolution NMR spectroscopy study at 9.4T. PLoS One 2014; 9:e88562. [PMID: 24533108 PMCID: PMC3922890 DOI: 10.1371/journal.pone.0088562] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 01/13/2014] [Indexed: 02/05/2023] Open
Abstract
Proton magnetic resonance spectroscopy (¹H-MRS) has been used to provide useful information about the neurochemical changes reflecting early pathological alterations in Alzheimer's disease (AD) brain. In this study, we have longitudinally measured the hippocampal neurochemical profile in vitro in senescent mice induced with chronic injection of D-Galactose and NaNO₂, at different time point from day 30 to day 70 with a 10-day interval. Pathological brain alterations induced by D-Galactose and NaNO₂ were monitored through hematoxylin and eosin (HE) staining, Congo red staining and bielschowsky silver staining, and the cognition deficits were assessed via Morris Water Maze (MWM) test. This D-galactose and NaNO₂ treated mouse model, characterized by an early-onset memory dysfunction, a robust neuronal loss, amyloid plaques and neurofibrillary tangles in hippocampal subdivision, well mimics a prodromal Alzheimer's phenotype. Consistent with previously published in vivo ¹H MRS findings in human AD patients and AD transgenic mice, our in vitro ¹H MRS on the perchloric acid extractions of hippocampus in senescent mice observed significant decreases of N-acetylaspartate (NAA) and Glutamate (Glu) but an increase in Myo-inositol (mIns). Elevated mIns occurred prior to the reduction of NAA and Glu during the progression of aging. In addition, changes in mIns, NAA and Glu were found to precede pathological abnormalities. Overall, our in vitro findings in senescent mice validated the concept that hippocampal neurochemical alternations preceded the pathological changes of the brain, and could serve as potential markers of AD progression. Reductions of NAA and Glu can be interpreted in terms of neuronal degeneration and dysfunctions in glutamatergic activity that may contribute to the pathophysiological mechanisms underlying AD. Elevated mIns might be related to glial activation. Further experiments are needed to explore the potential value of mIns in the early diagnosis of AD, to verify whether glial cell proliferation occurs earlier than neuronal changes.
Collapse
Affiliation(s)
- Yan Lin
- Department of Medical Imaging, The Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Jianli Yao
- Department of Medical Imaging, The Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong Province, China
- Sichuan Provincial Tumor Hospital, Chengdu, China
| | - Yaowen Chen
- Shantou University Central Laboratory and NMR Unit, Shantou, Guangdong Province, China
| | - Li Pang
- Department of Medical Imaging, The Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Haihong Li
- Mental Health Center of Shantou University Medical College, Shantou, Guangdong Province, China
| | - Zhen Cao
- Department of Medical Imaging, The Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Kezeng You
- Department of Medical Imaging, The Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Haiyang Dai
- Department of Medical Imaging, The Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong Province, China
| | - Renhua Wu
- Department of Medical Imaging, The Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong Province, China
- Key Laboratory of Molecular Imaging of Guangdong Province, Shantou, China
- * E-mail:
| |
Collapse
|
38
|
Stephenson MC, Leverton E, Khoo EYH, Poucher SM, Johansson L, Lockton JA, Eriksson JW, Mansell P, Morris PG, MacDonald IA. Variability in fasting lipid and glycogen contents in hepatic and skeletal muscle tissue in subjects with and without type 2 diabetes: a 1H and 13C MRS study. NMR IN BIOMEDICINE 2013; 26:1518-1526. [PMID: 23836451 DOI: 10.1002/nbm.2985] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 04/19/2013] [Accepted: 05/14/2013] [Indexed: 06/02/2023]
Abstract
The measurement of tissue lipid and glycogen contents and the establishment of normal levels of variability are important when assessing changes caused by pathology or treatment. We measured hepatic and skeletal muscle lipid and glycogen levels using (1)H and (13)C MRS at 3 T in groups of subjects with and without type 2 diabetes. Within-visit reproducibility, due to repositioning and instrument errors was determined from repeat measurements made over 1 h. Natural variability was assessed from separate measurements made on three occasions over 1 month. Hepatic lipid content was greater in subjects with diabetes relative to healthy subjects (p = 0.03), whereas levels of hepatic and skeletal muscle glycogen, and of intra- and extra-myocellular lipid, were similar. The single-session reproducibility values (coefficient of variation, CV) for hepatic lipid content were 12% and 7% in groups of subjects with and without diabetes, respectively. The variability of hepatic lipid content over 1 month was greater than the reproducibility, with CV = 22% (p = 0.08) and CV = 44% (p = 0.004) in subjects with and without diabetes, respectively. Similarly, levels of variation in basal hepatic glycogen concentrations (subjects with diabetes, CV = 38%; healthy volunteers, CV = 35%) were significantly larger than single-session reproducibility values (CV = 17%, p = 0.02 and CV = 13%, p = 0.05, respectively), indicating substantial biological changes in basal concentrations over 1 month. There was a decreasing correlation in measurements of both hepatic lipid and glycogen content with increasing time between scans. Levels of variability in intra- and extra-myocellular lipid in the soleus muscle, and glycogen concentrations in the gastrocnemius muscle, tended to be larger than expected from single-session reproducibility, although these did not reach significance.
Collapse
Affiliation(s)
- M C Stephenson
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Systematic regional variations of GABA, glutamine, and glutamate concentrations follow receptor fingerprints of human cingulate cortex. J Neurosci 2013; 33:12698-704. [PMID: 23904606 DOI: 10.1523/jneurosci.1758-13.2013] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Magnetic resonance spectroscopy (MRS) of glutamatergic or GABAergic measures in anterior cingulate cortex (ACC) was found altered in psychiatric disorders and predictive of interindividual variations of functional responses in healthy populations. Several ACC subregions have been parcellated into receptor-architectonically different portions with heterogeneous fingerprints for excitatory and inhibitory receptors. Similarly, these subregions overlap with functionally distinct regions showing opposed signal changes toward stimulation or resting conditions. We therefore investigated whether receptor-architectonical and functional segregation of the cingulate cortex in humans was also reflected in its local concentrations of glutamate (Glu), glutamine (Gln), and GABA. To accomplish a multiregion estimation of all three metabolites in one robust and reliable session, we used an optimized 7T-stimulated echo-acquisition mode method with variable-rate selective excitation pulses. Our results demonstrated that, ensuring high data retest reliability, four cingulate subregions discerning e.g., pregenual ACC (pgACC) from anterior mid-cingulate cortex showed different metabolite concentrations and ratios reflective of regionally specific inhibition/excitation balance. These findings could be controlled for potential influences of local gray matter variations or MRS voxel-placement deviations. Pregenual ACC was found to have significantly higher GABA and Glu concentrations than other regions. This pattern was not paralleled by Gln concentrations, which for both absolute and relative values showed a rostrocaudal gradient with highest values in pgACC. Increased excitatory Glu and inhibitory GABA in pgACC were shown to follow a regional segregation agreeing with recently shown receptor-architectonic GABAB receptor distribution in ACC, whereas Gln distribution followed a pattern of AMPA receptors.
Collapse
|
40
|
Regatte RR. Why buy an expensive ($7 million) 7T MRI system for biomedical research? J Magn Reson Imaging 2013; 40:280-2. [PMID: 24123421 DOI: 10.1002/jmri.24444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 09/11/2013] [Indexed: 12/26/2022] Open
Affiliation(s)
- Ravinder R Regatte
- Quantitative Multinuclear Musculoskeletal Imaging Group (QMMIG), Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, New York, NY, USA
| |
Collapse
|
41
|
Wijtenburg SA, Rowland LM, Edden RA, Barker PB. Reproducibility of brain spectroscopy at 7T using conventional localization and spectral editing techniques. J Magn Reson Imaging 2013; 38:460-7. [PMID: 23292856 PMCID: PMC3620961 DOI: 10.1002/jmri.23997] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 11/20/2012] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To evaluate the reproducibility of spectroscopic measurements from the anterior cingulate (AC) and the dorsolateral prefrontal cortex (DLPFC) regions at 7T using a 32-channel head coil. MATERIALS AND METHODS Spectra were acquired in four healthy subjects each scanned twice using a stimulated echo acquisition mode (STEAM) sequence, and a MEGA-PRESS-IVS sequence for gamma-aminobutyric acid (GABA) editing. STEAM spectra were quantified using LCModel, whereas MEGA-PRESS-IVS data were analyzed using peak integrals determined using in-house software. Mean coefficient of variation (CV) and mean absolute difference between visits were calculated. RESULTS For the AC STEAM dataset, the mean CV between visits was 6.2% for prominent metabolites such as N-acetylaspartate (NAA), total creatine (tCr), and total choline (tCho) and 6.3% for low signal-to-noise ratio (SNR) metabolites such as glutamate (Glu), glutamine (Gln), and GABA. The mean CV between visits for the DLPFC STEAM dataset was 8.5% for prominent metabolites and 21% for lower SNR metabolites. In the AC, the reproducibility measures for GABA were superior for STEAM compared to MEGA-PRESS-IVS (mean CV of 3.5% vs. 13.6%), but the opposite pattern was observed in the DLPFC region (mean CV of 16.2% vs. 13.4%). CONCLUSION 7T MR spectroscopy of the AC and DLPFC using both short TE STEAM and MEGA-PRESS-IVS sequences provide excellent reproducibility of 12 metabolites, including GABA.
Collapse
Affiliation(s)
- S. Andrea Wijtenburg
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Laura M. Rowland
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Richard A.E. Edden
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Peter B. Barker
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| |
Collapse
|
42
|
Hall EL, Stephenson MC, Price D, Morris PG. Methodology for improved detection of low concentration metabolites in MRS: optimised combination of signals from multi-element coil arrays. Neuroimage 2013; 86:35-42. [PMID: 23639258 DOI: 10.1016/j.neuroimage.2013.04.077] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 04/16/2013] [Accepted: 04/17/2013] [Indexed: 01/08/2023] Open
Abstract
State of the art magnetic resonance imaging (MRI) scanners are generally equipped with multi-element receive coils; 16 or 32 channel coils are common. Their development has been predominant for parallel imaging to enable faster scanning. Less consideration has been given to localized magnetic resonance spectroscopy (MRS). Multinuclear studies, for example (31)P or (13)C MRS, are often conducted with a single element coil located over the region of interest. (1)H MRS studies have generally employed the same multi-element coils used for MRI, but little consideration has been given as to how the spectroscopic data from the different channels are combined. In many cases it is simply co-added with detrimental effect on the signal to noise ratio. In this study, we derive the optimum method for combining multi-coil data, namely weighting with the ratio of signal to the square of the noise. We show that provided that the noise is uncorrelated, this is the theoretical optimal combination. The method is demonstrated for in vivo proton MRS data acquired using a 32 channel receive coil at 7T in four different brain areas; left motor and right motor, occipital cortex and medial frontal cortex.
Collapse
Affiliation(s)
- Emma L Hall
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK.
| | - Mary C Stephenson
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Darren Price
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Peter G Morris
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| |
Collapse
|
43
|
Good P. Does infectious fever relieve autistic behavior by releasing glutamine from skeletal muscles as provisional fuel? Med Hypotheses 2013; 80:1-12. [DOI: 10.1016/j.mehy.2012.08.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Revised: 08/25/2012] [Accepted: 08/30/2012] [Indexed: 01/01/2023]
|
44
|
Salvadore G, van der Veen JW, Zhang Y, Marenco S, Machado-Vieira R, Baumann J, Ibrahim LA, Luckenbaugh DA, Shen J, Drevets WC, Zarate CA. An investigation of amino-acid neurotransmitters as potential predictors of clinical improvement to ketamine in depression. Int J Neuropsychopharmacol 2012; 15:1063-72. [PMID: 22040773 PMCID: PMC3342437 DOI: 10.1017/s1461145711001593] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Amino-acid neurotransmitter system dysfunction plays a major role in the pathophysiology of major depressive disorder (MDD). We used proton magnetic resonance spectroscopy (¹H-MRS) to investigate whether prefrontal levels of amino-acid neurotransmitters predict antidepressant response to a single intravenous infusion of the N-methyl-D-aspartate (NMDA) antagonist ketamine in MDD patients. Fourteen drug-free patients with MDD were scanned 1-3 d before receiving a single intravenous infusion of ketamine (0.5 mg/kg). We measured gamma aminobutyric acid (GABA), glutamate, and Glx/glutamate ratio (a surrogate marker of glutamine) in the ventromedial prefrontal cortex (VM-PFC) and the dorsomedial/dorsal anterolateral prefrontal cortex (DM/DA-PFC). Correlation analyses were conducted to determine whether pretreatment GABA, glutamate, or Glx/glutamate ratio predicted change in depressive and anxiety symptoms 230 min after ketamine administration. Pretreatment GABA or glutamate did not correlate with improved depressive symptoms in either of the two regions of interest (p>0.1); pretreatment Glx/glutamate ratio in the DM/DA-PFC was negatively correlated with improvement in depressive symptoms [r s(11)=-0.57, p<0.05]. Pretreatment glutamate levels in the VM-PFC were positively correlated with improvement in anxiety symptoms [r s(11)=0.57, p<0.05]. The findings suggest an association between lower Glx/glutamate ratio and greater improvement in response to ketamine treatment. Because glutamine is mainly contained in glia, the decreased Glx/glutamate ratio observed in this study may reflect the reduction in glial cells found in the same regions in post-mortem studies of individuals with MDD, and suggests that the presence of this neuropathological construct may be associated with antidepressant responsiveness to ketamine.
Collapse
Affiliation(s)
- Giacomo Salvadore
- Experimental Therapeutics and Pathophysiology Branch, Division of Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Advanced MR methods at ultra-high field (7 Tesla) for clinical musculoskeletal applications. Eur Radiol 2012; 22:2338-46. [DOI: 10.1007/s00330-012-2508-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 05/02/2012] [Accepted: 05/04/2012] [Indexed: 12/16/2022]
|
46
|
Moser E, Stahlberg F, Ladd ME, Trattnig S. 7-T MR--from research to clinical applications? NMR IN BIOMEDICINE 2012; 25:695-716. [PMID: 22102481 DOI: 10.1002/nbm.1794] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 08/25/2011] [Accepted: 08/31/2011] [Indexed: 05/31/2023]
Abstract
Over 20,000 MR systems are currently installed worldwide and, although the majority operate at magnetic fields of 1.5 T and below (i.e. about 70%), experience with 3-T (in high-field clinical diagnostic imaging and research) and 7-T (research only) human MR scanners points to a future in functional and metabolic MR diagnostics. Complementary to previous studies, this review attempts to provide an overview of ultrahigh-field MR research with special emphasis on emerging clinical applications at 7 T. We provide a short summary of the technical development and the current status of installed MR systems. The advantages and challenges of ultrahigh-field MRI and MRS are discussed with special emphasis on radiofrequency inhomogeneity, relaxation times, signal-to-noise improvements, susceptibility effects, chemical shifts, specific absorption rate and other safety issues. In terms of applications, we focus on the topics most likely to gain significantly from 7-T MR, i.e. brain imaging and spectroscopy and musculoskeletal imaging, but also body imaging, which is particularly challenging. Examples are given to demonstrate the advantages of susceptibility-weighted imaging, time-of-flight MR angiography, high-resolution functional MRI, (1)H and (31)P MRSI in the human brain, sodium and functional imaging of cartilage and the first results (and artefacts) using an eight-channel body array, suggesting future areas of research that should be intensified in order to fully explore the potential of 7-T MR systems for use in clinical diagnosis.
Collapse
Affiliation(s)
- Ewald Moser
- Centre for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
| | | | | | | |
Collapse
|
47
|
Advances in ultra-high field MRI for the clinical management of patients with brain tumors. Curr Opin Neurol 2012; 24:605-15. [PMID: 22045220 DOI: 10.1097/wco.0b013e32834cd495] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
PURPOSE OF REVIEW The last 5 years have seen the number of ultra-high field (UHF; 7 T and beyond) MRI scanners nearly double. Benefits include improved specificity, better sensitivity for signal-starved compounds, and the ability to detect, quantify, and monitor tumor activity and treatment effects. This is especially important in the current climate in which new treatments alter established markers of tumor and the surrounding environment, confounding traditional response criteria. RECENT FINDINGS Intra-tumoral heterogeneity and dramatic improvement in spatial localization have been observed with 7 and 8 T high-resolution T2-weighted and T2*-weighted imaging. This depiction of lesions that were not readily detected at lower field improved the classification of glioma. Sub-millimeter visualization of microvasculature has facilitated the detection of microbleeds associated with long-term effects of radiation. New metabolic markers seen at UHF may also assist in distinguishing tumor progression from treatment effect. SUMMARY Although progress has been limited by technical challenges, initial experience has demonstrated the promise of 7-T MRI in advancing existing paradigms for diagnosing, monitoring, and managing patients with brain tumors. The success of these systems will depend upon what new information can be gained by UHF, rather than simply improving the quality of the current lower field standard.
Collapse
|