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Azilinon M, Makhalova J, Zaaraoui W, Medina Villalon S, Viout P, Roussel T, El Mendili MM, Ridley B, Ranjeva J, Bartolomei F, Jirsa V, Guye M. Combining sodium MRI, proton MR spectroscopic imaging, and intracerebral EEG in epilepsy. Hum Brain Mapp 2022; 44:825-840. [PMID: 36217746 PMCID: PMC9842896 DOI: 10.1002/hbm.26102] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 09/12/2022] [Accepted: 09/17/2022] [Indexed: 01/25/2023] Open
Abstract
Whole brain ionic and metabolic imaging has potential as a powerful tool for the characterization of brain diseases. We combined sodium MRI (23 Na MRI) and 1 H-MR Spectroscopic Imaging (1 H-MRSI), assessing changes within epileptogenic networks in comparison with electrophysiologically normal networks as defined by stereotactic EEG (SEEG) recordings analysis. We applied a multi-echo density adapted 3D projection reconstruction pulse sequence at 7 T (23 Na-MRI) and a 3D echo-planar spectroscopic imaging sequence at 3 T (1 H-MRSI) in 19 patients suffering from drug-resistant focal epilepsy who underwent presurgical SEEG. We investigated 23 Na MRI parameters including total sodium concentration (TSC) and the sodium signal fraction associated with the short component of T2 * decay (f), alongside the level of metabolites N-acetyl aspartate (NAA), choline compounds (Cho), and total creatine (tCr). All measures were extracted from spherical regions of interest (ROIs) centered between two adjacent SEEG electrode contacts and z-scored against the same ROI in controls. Group comparison showed a significant increase in f only in the epileptogenic zone (EZ) compared to controls and compared to patients' propagation zone (PZ) and non-involved zone (NIZ). TSC was significantly increased in all patients' regions compared to controls. Conversely, NAA levels were significantly lower in patients compared to controls, and lower in the EZ compared to PZ and NIZ. Multiple regression analyzing the relationship between sodium and metabolites levels revealed significant relations in PZ and in NIZ but not in EZ. Our results are in agreement with the energetic failure hypothesis in epileptic regions associated with widespread tissue reorganization.
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Affiliation(s)
- Mikhael Azilinon
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Julia Makhalova
- APHM, Timone Hospital, CEMEREMMarseilleFrance,Epileptology DepartmentAPHM, Timone HospitalMarseilleFrance
| | - Wafaa Zaaraoui
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Samuel Medina Villalon
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance,Epileptology DepartmentAPHM, Timone HospitalMarseilleFrance
| | - Patrick Viout
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Tangi Roussel
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Mohamed M. El Mendili
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Ben Ridley
- IRCCS Istituto delle Scienze Neurologiche di BolognaBolognaItaly
| | - Jean‐Philippe Ranjeva
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
| | - Fabrice Bartolomei
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance,Epileptology DepartmentAPHM, Timone HospitalMarseilleFrance
| | - Viktor Jirsa
- Aix Marseille Univ, INSERM, INS, Inst Neurosci SystMarseilleFrance
| | - Maxime Guye
- Aix Marseille Univ, CNRS, CRMBMMarseilleFrance,APHM, Timone Hospital, CEMEREMMarseilleFrance
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van Vliet EA, Immonen R, Prager O, Friedman A, Bankstahl JP, Wright DK, O'Brien TJ, Potschka H, Gröhn O, Harris NG. A companion to the preclinical common data elements and case report forms for in vivo rodent neuroimaging: A report of the TASK3-WG3 Neuroimaging Working Group of the ILAE/AES Joint Translational Task Force. Epilepsia Open 2022. [PMID: 35962745 DOI: 10.1002/epi4.12643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 02/01/2022] [Indexed: 11/10/2022] Open
Abstract
The International League Against Epilepsy/American Epilepsy Society (ILAE/AES) Joint Translational Task Force established the TASK3 working groups to create common data elements (CDEs) for various aspects of preclinical epilepsy research studies, which could help improve the standardization of experimental designs. In this article, we discuss CDEs for neuroimaging data that are collected in rodent models of epilepsy, with a focus on adult rats and mice. We provide detailed CDE tables and case report forms (CRFs), and with this companion manuscript, we discuss the methodologies for several imaging modalities and the parameters that can be collected.
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Affiliation(s)
- Erwin A van Vliet
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
- Amsterdam UMC Location University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Riikka Immonen
- A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Ofer Prager
- Departments of Physiology and Cell Biology, Cognitive and Brain Sciences, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Alon Friedman
- Departments of Physiology and Cell Biology, Cognitive and Brain Sciences, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Department of Medical Neuroscience and Brain Repair Center, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jens P Bankstahl
- Department of Nuclear Medicine, Hannover Medical School, Hannover, Germany
| | - David K Wright
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Terence J O'Brien
- The Royal Melbourne Hospital, The University of Melbourne, The Alfred Hospital, Monash University, Melbourne, Victoria, Australia
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University, Munich, Germany
| | - Olli Gröhn
- A.I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Neil G Harris
- Department of Neurosurgery UCLA, UCLA Brain Injury Research Center, Los Angeles, California, USA
- Intellectual and Developmental Disabilities Research Center, UCLA, Los Angeles, California, USA
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Chen G, Zhang Z, Wang M, Geng Y, Jin B, Aung T. Update on the Neuroimaging and Electroencephalographic Biomarkers of Epileptogenesis: A Literature Review. Front Neurol 2021; 12:738658. [PMID: 34512540 PMCID: PMC8429485 DOI: 10.3389/fneur.2021.738658] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/09/2021] [Indexed: 11/13/2022] Open
Abstract
Epilepsy is one of the most common debilitating neurological disorders that lead to severe socio-cognitive dysfunction. While there are currently more than 30 antiseizure medications available for the treatment and prevention of seizures, none address the prevention of epileptogenesis that leading to the development of epilepsy following a potential brain insult. Hence, there is a growing need for the identification of accurate biomarkers of epileptogenesis that enable the prediction of epilepsy following a known brain insult. Although recent studies using various neuroimages and electroencephalography have found promising biomarkers of epileptogenesis, their utility needs to be further validated in larger clinical trials. In this literature review, we searched the Medline, Pubmed, and Embase databases using the following search algorithm: "epileptogenesis" and "biomarker" and "EEG" or "electroencephalography" or "neuroimaging" limited to publications in English. We presented a comprehensive overview of recent innovations in the role of neuroimaging and EEG in identifying reliable biomarkers of epileptogenesis.
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Affiliation(s)
- Guihua Chen
- Department of Neurology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Zheyu Zhang
- The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China
| | - Meiping Wang
- Department of Neurology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Yu Geng
- Department of Neurology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Bo Jin
- Department of Neurology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Thandar Aung
- Epilepsy Center, University of Pittsburgh, Pittsburgh, PA, United States
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Neuroimaging Biomarkers of Experimental Epileptogenesis and Refractory Epilepsy. Int J Mol Sci 2019; 20:ijms20010220. [PMID: 30626103 PMCID: PMC6337422 DOI: 10.3390/ijms20010220] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 12/31/2018] [Accepted: 01/03/2019] [Indexed: 11/17/2022] Open
Abstract
This article provides an overview of neuroimaging biomarkers in experimental epileptogenesis and refractory epilepsy. Neuroimaging represents a gold standard and clinically translatable technique to identify neuropathological changes in epileptogenesis and longitudinally monitor its progression after a precipitating injury. Neuroimaging studies, along with molecular studies from animal models, have greatly improved our understanding of the neuropathology of epilepsy, such as the hallmark hippocampus sclerosis. Animal models are effective for differentiating the different stages of epileptogenesis. Neuroimaging in experimental epilepsy provides unique information about anatomic, functional, and metabolic alterations linked to epileptogenesis. Recently, several in vivo biomarkers for epileptogenesis have been investigated for characterizing neuronal loss, inflammation, blood-brain barrier alterations, changes in neurotransmitter density, neurovascular coupling, cerebral blood flow and volume, network connectivity, and metabolic activity in the brain. Magnetic resonance imaging (MRI) is a sensitive method for detecting structural and functional changes in the brain, especially to identify region-specific neuronal damage patterns in epilepsy. Positron emission tomography (PET) and single-photon emission computerized tomography are helpful to elucidate key functional alterations, especially in areas of brain metabolism and molecular patterns, and can help monitor pathology of epileptic disorders. Multimodal procedures such as PET-MRI integrated systems are desired for refractory epilepsy. Validated biomarkers are warranted for early identification of people at risk for epilepsy and monitoring of the progression of medical interventions.
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Ji Y, Lu D, Wu L, Qiu B, Song YQ, Sun PZ. Preliminary evaluation of accelerated microscopic diffusional kurtosis imaging (μDKI) in a rodent model of epilepsy. Magn Reson Imaging 2018; 56:90-95. [PMID: 30352270 DOI: 10.1016/j.mri.2018.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 10/15/2018] [Accepted: 10/18/2018] [Indexed: 12/23/2022]
Abstract
PURPOSE Our study aimed to develop accelerated microscopic diffusional kurtosis imaging (μDKI) and preliminarily evaluated it in a rodent model of chronic epilepsy. METHODS We investigated two μDKI acceleration schemes of reduced sampling density and angular range in a phantom and wild-type rats, and further tested μDKI method in pilocarpine-induced epilepsy rats using a 4.7 Tesla MRI. Single slice average μDapp and μKapp maps were derived, and Nissl staining was obtained. RESULTS The kurtosis maps from two accelerated μDKI sampling schemes (sampling density and range) are very similar to that using fully sampled data (SSIM > 0.95). For the epileptic models, μDKI showed noticeably different contrast from those obtained with conventional DKI. Specifically, the average μKapp was significantly less than that of the average of Kapp (0.15 ± 0.01 vs. 0.47 ± 0.02) in the ventricle. CONCLUSIONS Our study demonstrated the feasibility of accelerated in vivo μDKI. Our work revealed that μDKI provides complementary information to conventional DKI method, suggesting that advanced DKI sequences are promising to elucidate tissue microstructure in neurological diseases.
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Affiliation(s)
- Yang Ji
- Center for Biomedical Engineering, Department of Electronic Science and Technology, University of Science and Technology of China, Hefei, China; Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States of America
| | - Dongshuang Lu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States of America
| | - Limin Wu
- Neuroscience Center, Department of Pediatrics, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States of America
| | - Bensheng Qiu
- Center for Biomedical Engineering, Department of Electronic Science and Technology, University of Science and Technology of China, Hefei, China
| | - Yi-Qiao Song
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States of America; Schlumberger-Doll Research Center, Cambridge, MA, United States of America
| | - Phillip Zhe Sun
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States of America; Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States of America; Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States of America.
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Neuroimaging in animal models of epilepsy. Neuroscience 2017; 358:277-299. [DOI: 10.1016/j.neuroscience.2017.06.062] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/27/2017] [Accepted: 06/28/2017] [Indexed: 02/06/2023]
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Pearce PS, Wu Y, Rapuano A, Kelly KM, de Lanerolle N, Pan JW. Metabolic injury in a variable rat model of post-status epilepticus. Epilepsia 2016; 57:1978-1986. [PMID: 27943308 PMCID: PMC5215597 DOI: 10.1111/epi.13588] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2016] [Indexed: 11/27/2022]
Abstract
OBJECTIVE In vivo studies of epilepsy typically use prolonged status epilepticus to generate recurrent seizures. However, reports on variable status duration have found discrete differences in injury after 40-50 min of seizures, suggesting a pathophysiologic sensitivity to seizure duration. In this report we take a multivariate cluster analysis to study a short duration status epilepticus model using in vivo 7T magnetic resonance spectroscopy (MRS) and histologic evaluation. METHODS The Hellier Dudek model was applied with 45 min of status epilepticus after which the animals were imaged twice, at 3 days and 3 weeks post-status epilepticus. Single voxel point resolved spectroscopy (PRESS) MRS was used to acquire data from the dentate gyrus and CA3 region of the hippocampus, assessing metabolite ratios to total creatine (tCr). In a subset of animals after the second imaging study, brains were analyzed histologically by Nissl staining. RESULTS A hierarchical cluster analysis performed on the 3-day data from 21 kainate-treated animals (dentate gyrus voxel) segregated into two clusters, denoted by KM (more injured, n = 6) and KL (less injured, n = 15). Although there was no difference in kainate dosing or seizure count between them, the metabolic pattern of injury was different. The KM group displayed the largest significant changes in neuronal and glial parameters; the KL group displayed milder but significant changes. At 3 weeks, the KL group returned to normal compared to controls, whereas the KM group persisted with depressed N-acetyl aspartate (NAA)/tCr, glutamate/tCr, and increased inositol/tCr and glutamine/tCr. The classification was also consistent with subsequent histologic patterns at 3 weeks. SIGNIFICANCE Although a short status period might be expected to generate a continuous distribution of metabolic injury, these data show that the short Hellier Dudek model appears to generate two levels of injury. The changes seen in segregated groups persisted into 3 weeks, and can be interpreted according to neuronal and glial biomarkers consistent with histology results.
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Affiliation(s)
- Patrice S Pearce
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A
| | - Yijen Wu
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A
| | - Amedeo Rapuano
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut, U.S.A
| | - Kevin M Kelly
- Department of Neurology, Allegheny Singer Research Institute, Pittsburgh, Pennsylvania, U.S.A
| | - Nihal de Lanerolle
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut, U.S.A
| | - Jullie W Pan
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A.,Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A
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Febo M, Foster TC. Preclinical Magnetic Resonance Imaging and Spectroscopy Studies of Memory, Aging, and Cognitive Decline. Front Aging Neurosci 2016; 8:158. [PMID: 27468264 PMCID: PMC4942756 DOI: 10.3389/fnagi.2016.00158] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 06/16/2016] [Indexed: 01/14/2023] Open
Abstract
Neuroimaging provides for non-invasive evaluation of brain structure and activity and has been employed to suggest possible mechanisms for cognitive aging in humans. However, these imaging procedures have limits in terms of defining cellular and molecular mechanisms. In contrast, investigations of cognitive aging in animal models have mostly utilized techniques that have offered insight on synaptic, cellular, genetic, and epigenetic mechanisms affecting memory. Studies employing magnetic resonance imaging and spectroscopy (MRI and MRS, respectively) in animal models have emerged as an integrative set of techniques bridging localized cellular/molecular phenomenon and broader in vivo neural network alterations. MRI methods are remarkably suited to longitudinal tracking of cognitive function over extended periods permitting examination of the trajectory of structural or activity related changes. Combined with molecular and electrophysiological tools to selectively drive activity within specific brain regions, recent studies have begun to unlock the meaning of fMRI signals in terms of the role of neural plasticity and types of neural activity that generate the signals. The techniques provide a unique opportunity to causally determine how memory-relevant synaptic activity is processed and how memories may be distributed or reconsolidated over time. The present review summarizes research employing animal MRI and MRS in the study of brain function, structure, and biochemistry, with a particular focus on age-related cognitive decline.
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Affiliation(s)
- Marcelo Febo
- Department of Psychiatry, William L. and Evelyn F. McKnight Brain Institute, University of Florida Gainesville, FL, USA
| | - Thomas C Foster
- Department of Neuroscience, William L. and Evelyn F. McKnight Brain Institute, University of Florida Gainesville, FL, USA
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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.
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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
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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.
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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.
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Obenaus A. Neuroimaging biomarkers for epilepsy: advances and relevance to glial cells. Neurochem Int 2013; 63:712-8. [PMID: 23665337 DOI: 10.1016/j.neuint.2013.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 04/24/2013] [Accepted: 05/01/2013] [Indexed: 12/11/2022]
Abstract
Glial cells play an important role in normal brain function and emerging evidence would suggest that their dysfunction may be responsible for some epileptic disease states. Neuroimaging of glial cells is desirable, but there are no clear methods to assess neither their function nor localization. Magnetic resonance imaging (MRI) is now part of a standardized epilepsy imaging protocol to assess patients. Structural volumetric and T2-weighted imaging changes can assist in making a positive diagnosis in a majority of patients. The alterations reported in structural and T2 imaging is predominantly thought to reflect early neuronal loss followed by glial hypertrophy. MR spectroscopy for myo-inositol is a being pursued to identify glial alterations along with neuronal markers. Diffusion weighted imaging (DWI) is ideal for acute epileptiform events, but is not sensitive to either glial cells or neuronal long-term changes found in epilepsy. However, DWI variants such as diffusion tensor imaging or q-space imaging may shed additional light on aberrant glial function in the future. The sensitivity and specificity of PET radioligands, including those targeting glial cells (translocator protein) hold promise in being able to image glial cells. As the role of glial function/dysfunction in epilepsy becomes more apparent neuroimaging methods will evolve to assist the clinician and researcher in visualizing their location and function.
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Affiliation(s)
- Andre Obenaus
- Department of Pediatrics, School of Medicine, Loma Linda University, Loma Linda, CA, USA; Division of Interdisciplinary Studies, School of Behavioral Health, Loma Linda University, Loma Linda, CA, USA; Cell and Molecular Development and Biology Program, University of California, Riverside, CA, USA; Neuroscience Graduate Program, University of California, Riverside, CA, USA.
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