1
|
Alraddadi EA, Khojah AM, Alamri FF, Kecheck HK, Altaf WF, Khouqeer Y. Potential role of creatine as an anticonvulsant agent: evidence from preclinical studies. Front Neurosci 2023; 17:1201971. [PMID: 37456992 PMCID: PMC10339234 DOI: 10.3389/fnins.2023.1201971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 06/12/2023] [Indexed: 07/18/2023] Open
Abstract
Epilepsy is one of the most common neurological disorders affecting people of all ages representing a significant social and public health burden. Current therapeutic options for epilepsy are not effective in a significant proportion of patients suggesting a need for identifying novel targets for the development of more effective therapeutics. There is growing evidence from animal and human studies suggesting a role of impaired brain energy metabolism and mitochondrial dysfunction in the development of epilepsy. Candidate compounds with the potential to target brain energetics have promising future in the management of epilepsy and other related neurological disorders. Creatine is a naturally occurring organic compound that serves as an energy buffer and energy shuttle in tissues, such as brain and skeletal muscle, that exhibit dynamic energy requirements. In this review, applications of creatine supplements in neurological conditions in which mitochondrial dysfunction is a central component in its pathology will be discussed. Currently, limited evidence mainly from preclinical animal studies suggest anticonvulsant properties of creatine; however, the exact mechanism remain to be elucidated. Future work should involve larger clinical trials of creatine used as an add-on therapy, followed by large clinical trials of creatine as monotherapy.
Collapse
Affiliation(s)
- Eman A. Alraddadi
- Department of Basic Sciences, College of Science and Health Professions, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
- King Abdullah International Medical Research Center, Jeddah, Saudi Arabia
| | - Abdulrahman M. Khojah
- Department of Basic Sciences, College of Science and Health Professions, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
- College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| | - Faisal F. Alamri
- Department of Basic Sciences, College of Science and Health Professions, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
- King Abdullah International Medical Research Center, Jeddah, Saudi Arabia
| | - Husun K. Kecheck
- Department of Basic Sciences, College of Science and Health Professions, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
- College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| | - Wid F. Altaf
- Department of Basic Sciences, College of Science and Health Professions, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
- College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| | - Yousef Khouqeer
- Department of Basic Sciences, College of Science and Health Professions, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
- College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| |
Collapse
|
2
|
Nicolo JP, O'Brien TJ, Kwan P. Role of cerebral glutamate in post-stroke epileptogenesis. NEUROIMAGE-CLINICAL 2019; 24:102069. [PMID: 31795040 PMCID: PMC6883323 DOI: 10.1016/j.nicl.2019.102069] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 10/13/2019] [Accepted: 11/03/2019] [Indexed: 01/17/2023]
Abstract
Stroke is one of the most important causes of acquired epilepsy in the adult population. While factors such as cortical involvement and haemorrhage have been associated with increased seizure risk, the mechanisms underlying the development of epilepsy after stroke remain unclear. One hypothesised mechanism is an excitotoxic effect of abnormal glutamate release following a stroke. Cerebral extracellular glutamate levels are known to rise in the setting of acute stroke, and numerous studies have implicated glutamate in the pathogenesis of seizures and epilepsy, both through direct measurement of glutamate from the epileptic brain and by analysis of receptors and transporters central to glutamate homeostasis. While experimental evidence suggests the cellular injury induced by glutamate exposure may lead to development of an epileptic phenotype, there is little direct data linking the rise in glutamate during stroke with the later development of epilepsy. Clinical research in this field has been hampered by the lack of non-invasive methods to measure cerebral glutamate. However, with the increasing availability of 7T MRI technology, Magnetic Resonance Spectroscopy is able to better resolve glutamate from other chemical species at this field strength, and Glutamate Chemical Exchange Saturation Transfer (GluCEST) imaging has been applied to localise epileptic foci in non-lesional focal epilepsy. This review outlines the evidence implicating a pivotal role for cerebral glutamate in the development of post-stroke epilepsy, and exploring the role of MRI in studying glutamate as a biomarker and therefore its suitability as a molecular target for anti-epileptogenic therapies. We hypothesise that the rise in glutamate levels in the setting of acute stroke is a clinically relevant biomarker for the development of post-stroke epilepsy.
Collapse
Affiliation(s)
- John-Paul Nicolo
- Department of Neurology, Royal Melbourne Hospital, 300 Grattan Street Parkville Victoria Australia; Department of Neurology, Alfred Hospital, 55 Commercial Road, Melbourne Victoria Australia.
| | - Terence J O'Brien
- Department of Neuroscience, Monash University, Alfred Hospital, 55 Commercial Road, Melbourne Victoria Australia; Department of Medicine (The Royal Melbourne Hospital), The University of Melbourne, Royal Parade, Parkville Victoria Australia.
| | - Patrick Kwan
- Department of Neurology, Royal Melbourne Hospital, 300 Grattan Street Parkville Victoria Australia; Department of Neuroscience, Monash University, Alfred Hospital, 55 Commercial Road, Melbourne Victoria Australia.
| |
Collapse
|
3
|
Lee DH, Lee DW, Kwon JI, Woo CW, Kim ST, Lee JS, Choi CG, Kim KW, Kim JK, Woo DC. In Vivo Mapping and Quantification of Creatine Using Chemical Exchange Saturation Transfer Imaging in Rat Models of Epileptic Seizure. Mol Imaging Biol 2018; 21:232-239. [DOI: 10.1007/s11307-018-1243-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
4
|
Chen N, Liu C, Yan N, Hu W, Zhang JG, Ge Y, Meng FG. A macaque model of mesial temporal lobe epilepsy induced by unilateral intrahippocampal injection of kainic Acid. PLoS One 2013; 8:e72336. [PMID: 23991095 PMCID: PMC3753347 DOI: 10.1371/journal.pone.0072336] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 07/08/2013] [Indexed: 11/18/2022] Open
Abstract
Objective In order to better investigate the cause/effect relationships of human mesial temporal lobe epilepsy (mTLE), we hereby describe a new non-human primate model of mTLE. Methods Ten macaques were studied and divided into 2 groups: saline control group (n = 4) and kainic acid (KA) injection group (n = 6). All macaques were implanted bilaterally with subdural electrodes over temporal cortex and depth electrodes in CA3 hippocampal region. KA was stereotaxically injected into the right hippocampus of macaques. All animals were monitored by video and electrocorticography (ECoG) to assess status epilepticus (SE) and subsequent spontaneous recurrent seizures (SRS). Additionally, in order to evaluate brain injury produced by SE or SRS, we used both neuroimaging, including magnetic resonance image (MRI) & magnetic resonance spectroscopy (MRS), and histological pathology, including Nissl stainning and glial fibrillary acid protein (GFAP) immunostaining. Results The typical seizures were observed in the KA-injected animal model. Hippocampal sclerosis could be found by MRI & MRS. Hematoxylin and eosin (H&E) staining and GFAP immunostaining showed neuronal loss, proliferation of glial cells, formation of glial scars, and hippocampal atrophy. Electron microscopic analysis of hippocampal tissues revealed neuronal pyknosis, partial ribosome depolymerization, an abnormal reduction in rough endoplasmic reticulum size, expansion of Golgi vesicles and swollen star-shaped cells. Furthermore, we reported that KA was able to induce SE followed by SRS after a variable period of time. Similar to human mTLE, brain damage is confined to the hippocampus. Accordingly, hippocampal volume is in positive correlations with the neuronal cells count in the CA3, especially the ratio of neuron/glial cell. Conclusions The results suggest that a model of mTLE can be developed in macaques by intra-hippocampal injection of KA. Brain damage is confined to the hippocampus which is similar to the human mTLE. The hippocampal volume correlates with the extension of the hippocampal damage.
Collapse
Affiliation(s)
- Ning Chen
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Chong Liu
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Na Yan
- School of Public Health and Family Medicine, Capital Medical University, Beijing, China
| | - Wei Hu
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Jian-guo Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yan Ge
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Fan-gang Meng
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
- * E-mail:
| |
Collapse
|
5
|
|
6
|
Lee EM, Park GY, Im KC, Kim ST, Woo CW, Chung JH, Kim KS, Kim JS, Shon YM, Kim YI, Kang JK. Changes in glucose metabolism and metabolites during the epileptogenic process in the lithium-pilocarpine model of epilepsy. Epilepsia 2012; 53:860-9. [PMID: 22429025 DOI: 10.1111/j.1528-1167.2012.03432.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE The metabolic and biochemical changes that occur during epileptogenesis remain to be determined. (18) F-Fluorodeoxyglucose positron emission tomography (FDG-PET) and proton magnetic resonance spectroscopy ((1) H MRS) are noninvasive techniques that provide indirect information on ongoing pathologic changes. We, therefore, utilized these methods to assess changes in glucose metabolism and metabolites in the rat lithium-pilocarpine model of epilepsy as markers of epileptogenesis from baseline to chronic spontaneous recurrent seizures (SRS). METHODS PET and MRS were performed at baseline, and during the acute, subacute, silent, and chronic periods after lithium-pilocarpine induced status epilepticus (SE). Sequential changes in glucose metabolism on (18) F-FDG PET using SPM2 and the ratios of percent injected dose per gram (%ID)/g of regions of interest (ROIs) in the bilateral amygdala, hippocampus, basal ganglia with the thalamus, cortex, and hypothalamus normalized to the pons were determined. Voxels of interest (VOIs) on (1) H MRS were obtained at the right hippocampus and the basal ganglia. NAA/Cr levels and Cho/Cr at various time points were compared to baseline values. KEY FINDINGS Of 81 male Sprague-Dawley rats, 30 progressed to SRS. (18) F-FDG PET showed widespread global hypometabolism during the acute period, returning to baseline level during the subacute period. Glucose metabolism, however, declined in part of the hippocampus during the silent period, with the hypometabolic area progressively expanding to the entire limbic area during the chronic period. (1) H MRS showed that the NAA/Cr levels in the hippocampus and basal ganglia were reduced during the acute period and were not restored subsequently from the subacute to the chronic period without any significant change in the Cho/Cr ratio throughout the entire experiment. SIGNIFICANCE Serial metabolic and biochemical changes in the lithium-pilocarpine model of epilepsy indirectly represent the process of human epileptogenesis. Following initial irreversible neural damage by SE, global glucose metabolism transiently recovered during the subacute period without neuronal recovery. Progressive glucose hypometabolism in the limbic area during the silent and chronic periods may reflect the important role of the hippocampus in the formation of ongoing epileptic network during epileptogenesis.
Collapse
Affiliation(s)
- Eun Mi Lee
- Department of Neurology, Ulsan University Hospital, Ulsan, Korea
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Single-voxel magnetic resonance spectroscopy of brain tissue adjacent to arachnoid cysts of epileptic patients. Neurologist 2008; 14:382-9. [PMID: 19008744 DOI: 10.1097/nrl.0b013e318177819c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Intracranial arachnoid cysts (ACs) are usually asymptomatic, benign developmental anomalies. The most frequent clinical manifestations are cranial expansion, hydrocephaly, headache, epileptic seizures, psychomotor retardation, and aphasia. It is unknown whether there is a correlation between intracranial AC and epileptic seizures without obvious intracranial pressure signs. In vivo magnetic resonance spectroscopy is a technique used for the noninvasive investigation of the various metabolites of cerebral biochemical reactions. Magnetic resonance spectroscopy is also being used increasingly commonly in epileptogenic situations as a noninvasive technique. The purpose of this study was to evaluate the proton magnetic resonance spectroscopic pattern of the contents of tissue adjacent to AC and to determine whether there are any characteristic spectral patterns that may be helpful in evaluating whether these lesions are epileptogenic foci. In conclusion, although the number of cases was limited, this finding may be seen as indicating that there is no association between AC and epilepsy.
Collapse
|
8
|
Gomes WA, Lado FA, de Lanerolle NC, Takahashi K, Pan C, Hetherington HP. Spectroscopic imaging of the pilocarpine model of human epilepsy suggests that early NAA reduction predicts epilepsy. Magn Reson Med 2007; 58:230-5. [PMID: 17654595 DOI: 10.1002/mrm.21310] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Reduced hippocampal N-acetyl aspartate (NAA) is commonly observed in patients with advanced, chronic temporal lobe epilepsy (TLE). It is unclear, however, whether an NAA deficit is also present during the clinically quiescent latent period that characterizes early TLE. This question has important implications for the use of MR spectroscopic imaging (MRSI) in the early identification of patients at risk for TLE. To determine whether NAA is diminished during the latent period, we obtained high-resolution (1)H spectroscopic imaging during the latent period of the rat pilocarpine model of human TLE. We used actively detuneable surface reception and volume transmission coils to enhance sensitivity and a semiautomated voxel shifting method to accurately position voxels within the hippocampi. During the latent period, 2 and 7 d following pilocarpine treatment, hippocampal NAA was significantly reduced by 27.5 +/- 6.9% (P < 0.001) and 17.3 +/- 6.9% (P < 0.001) at 2 and 7 d, respectively. Quantitative estimates of neuronal loss at 7 d (2.3 +/- 7.7% reduction; P = 0.58, not significant) demonstrate that the NAA deficit is not due to neuron loss and therefore likely represents metabolic impairment of hippocampal neurons during the latent phase. Therefore, spectroscopic imaging provides an early marker for metabolic dysfunction in this model of TLE.
Collapse
Affiliation(s)
- W A Gomes
- Department of Radiology, Montefiore Medical Center, Bronx, New York 10467, USA.
| | | | | | | | | | | |
Collapse
|
9
|
Højrup S, Jensen FT, Hokland S, Simonsen C, Christensen T, Frøkiaer J, Pedersen M. Interobserver and within-subject variances of T2-relaxation time and 1H-metabolite ratios in the normal hippocampus. J Neuroradiol 2007; 34:198-204. [PMID: 17568675 DOI: 10.1016/j.neurad.2007.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE To investigate the magnetic resonance (MR) reproducibility of normal hippocampal volume (HV), temporal lobe volume (TLV), transversal relaxation time (T(2)) and (1)H-MR spectroscopy ((1)H-MRS) metabolite ratios. MATERIALS AND METHODS Two sets of HV, TLV, T(2) and MR spectroscopic metabolite signal ratios were determined in 27 healthy volunteers. HV and TLV were measured with a T(1)-weighted MR sequence; whereas T(2) measurements were performed with conventional spin-echo (CSE) and fast spin-echo (FSE) MR imaging sequences. The interobserver and within-subject variances of T(2) measurements were estimated. RESULTS Estimated right and left HV coefficients of variation (CV)=0.13. FSE T(2) measurements showed no significant differences in the interobserver (CV=0.02) and within-subject variances (CV=0.02). Measurements showed no differences in the interobserver (CV=0.02) and within-subject (CV=0.04) variances for the CSE T(2) of the right and left hippocampi. Metabolite ratios between N-acetyl aspartate (NAA) and creatine (Cr), choline (Cho) and creatine, and NAA and choline plus creatine (Cho + Cr) for the right hippocampus were 2.29+/-0.19, 1.52+/-0.14 and 0.91+/-0.05, respectively. Metabolite ratios for the left hippocampus were 2.18+/-0.10, 1.48+/-0.10 and 0.88+/-0.06, respectively. CONCLUSIONS HV, TLV, T(2) and (1)H MRS metabolite ratio measurements showed fair reproducibility with small CVs, and no differences in the interobserver and within-subject variances, including no differences between right and left TLV, and in the right and left T(2).
Collapse
Affiliation(s)
- S Højrup
- MR Research Center, Aarhus University Hospital, 8200 Aarhus, Denmark
| | | | | | | | | | | | | |
Collapse
|
10
|
Willmann O, Wennberg R, May T, Woermann FG, Pohlmann-Eden B. The role of 1H magnetic resonance spectroscopy in pre-operative evaluation for epilepsy surgery. A meta-analysis. Epilepsy Res 2006; 71:149-58. [PMID: 16890408 DOI: 10.1016/j.eplepsyres.2006.06.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Revised: 06/14/2006] [Accepted: 06/15/2006] [Indexed: 10/24/2022]
Abstract
PURPOSE We aimed to assess the additional pre-operative value of (1)H MRS in identifying the epileptogenic zone (EZ) for epilepsy surgery by performing a meta-analysis considering publications from 1992 to 2003. METHODS From an extensive computer and hand search 22 studies were included. For inclusion, studies had to report post-operative outcome and detailed diagnostic test results for each individual patient. Studies exclusively reporting on patients with brain tumors or on children were excluded. RESULTS Great heterogeneity among studies regarding methodological and technical aspects and concerning evaluation and interpretation of data was observed. Only patients with intractable temporal lobe epilepsy were presented. Sixty-four percent of all patients and 72% of patients with good outcome had an ipsilateral MRS abnormality concordant with the EZ. The positive predictive value of all patients with ipsilateral MRS abnormality for good outcome was 82%. An odds ratio weighted by inverse variance showed a 4.891 better chance of seizure free outcome [CI=1.965-12.172; Q=2.748; d.f.=5; critical chi2-value=11.07] in patients with an ipsilateral MRS abnormality when compared to patients with bilateral MRS abnormalities. Data for MRI-negative patients were conflicting. One study stressed a role for MRS in patients with bilateral hippocampal atrophy at MRI. CONCLUSIONS MRS still remains a research tool with clinical potential. Our findings indicate the connection of ipsilateral MRS abnormality to good outcome. The ability for prediction of post-operative outcome may depend on the assessed population. Prospective studies limited to non-localized ictal scalp EEG or MRI-negative patients are required for validation of these data.
Collapse
Affiliation(s)
- O Willmann
- Department of Neurology, University Hospital Mannheim, University of Heidelberg, Germany
| | | | | | | | | |
Collapse
|
11
|
Giove F, Garreffa G, Peca S, Carní M, Macrì MA, Di Bonaventura C, Vaudano AE, Giallonardo AT, Prencipe M, Bozzao L, Pantano P, Colonnese C, Maraviglia B. Metabolic alteration transients during paroxysmal activity in an epileptic patient with fixation-off sensitivity: a case study. Magn Reson Imaging 2006; 24:373-9. [PMID: 16677943 DOI: 10.1016/j.mri.2005.11.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Accepted: 11/21/2005] [Indexed: 11/28/2022]
Abstract
The purpose of this study was to investigate short-time metabolic variations related to continuous epileptic activity elicited by fixation-off sensitivity (FOS). Time-resolved magnetic resonance spectroscopy was performed on a patient on whom previous clinical findings clearly indicated presence of FOS. The epileptic focus was localized with a simultaneous electroencephalographic and functional magnetic resonance imaging study. The results showed a linear increase of the sum of glutamate and glutamine with time of paroxysmal activity in epileptic focus and much greater concentration of choline-containing compounds in focus than in the contralateral side.
Collapse
Affiliation(s)
- Federico Giove
- Museo storico della fisica e Centro di studi e ricerche Enrico Fermi, 00184 Rome, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Lee SK, Kim DW, Kim KK, Chung CK, Song IC, Chang KH. Effect of seizure on hippocampus in mesial temporal lobe epilepsy and neocortical epilepsy: an MRS study. Neuroradiology 2005; 47:916-23. [PMID: 16158277 DOI: 10.1007/s00234-005-1447-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2005] [Accepted: 06/06/2005] [Indexed: 11/24/2022]
Abstract
This study was performed to evaluate the effect of seizures on the bilateral hippocampus in mesial temporal lobe epilepsy (mTLE) and neocortical epilepsy by single voxel proton magnetic resonance spectroscopy (MRS). Forty-one patients with mTLE having unilateral hippocampal sclerosis and 43 patients with a neocortical epilepsy who underwent subsequent epilepsy surgery were recruited. Ninety-five percent confidence intervals of N-acetyl aspartate/choline (NAA/Cho) and NAA/creatine (NAA/Cr) ratios in 20 healthy control subjects were used as threshold values to determine abnormal NAA/Cho and NAA/Cr. NAA/Cho and NAA/Cr were significantly lower in the ipsilateral hippocampus of mTLE and neocortical epilepsy. Using asymmetry indices for patients with bilaterally abnormal ratios of NAA/Cho and NAA/Cr in addition to using unilateral abnormal ratio, the seizure focus was correctly lateralized in 65.9% of patients with mTLE and 48.8% of neocortical epilepsy patients. Bilateral NAA/Cho abnormality was significantly related to a poor surgical outcome in mTLE. No significant relationship was found between the results of NAA/Cho or NAA/Cr and surgical outcome in neocortical epilepsy. The mean contralateral NAA/Cr ratio of the hippocampus in mTLE was significantly lower in patients with a history of secondary generalized tonic-clonic seizure (SGTCS) than in those without. Our results demonstrate effects of seizures on the hippocampi in neocortical epilepsy and the relation between SGTCS and NAA/Cr of the contralateral hippocampus in mTLE. This proves the presence of a seizure effect on the hippocampus in neocortical epilepsy as well as in mTLE.
Collapse
Affiliation(s)
- S K Lee
- Department of Neurology, Seoul National University College of Medicine, Seoul National University Hospital, Chongno ku, Korea.
| | | | | | | | | | | |
Collapse
|
13
|
Cormack F, Gadian DG, Vargha-Khadem F, Cross JH, Connelly A, Baldeweg T. Extra-hippocampal grey matter density abnormalities in paediatric mesial temporal sclerosis. Neuroimage 2005; 27:635-43. [PMID: 16006149 DOI: 10.1016/j.neuroimage.2005.05.023] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2004] [Revised: 03/24/2005] [Accepted: 05/03/2005] [Indexed: 10/25/2022] Open
Abstract
The aim of this study was to identify grey matter density abnormalities in children with temporal lobe epilepsy and mesial temporal sclerosis. Magnetic resonance T1 weighted 3D datasets were obtained in children with temporal lobe epilepsy (20 left and 10 right sided, mean age 11.9 years, range 6.6-17.5) and compared to scans obtained from age-matched controls (n = 22, mean age 12.8 years, range 7.1-17.5) using voxel-based morphometry. This method detected reduced grey matter ipsilateral to the seizure focus not only in the hippocampus, but also in the lateral temporal lobe and in extra-temporal regions including the thalamus, posterior cingulate cortex and cerebellum. Bilateral differences were present in the frontal and parietal opercular cortices and lateral temporal regions. These grey matter density reductions broadly reflect the pattern of hippocampal connections and may be caused by the disruption of cortical development by the recurrent seizures, as well as by loss of functional input from the sclerotic hippocampus.
Collapse
Affiliation(s)
- Francesca Cormack
- Developmental Cognitive Neuroscience Unit, Institute of Child Health, University College London, London WC1N 1EH, UK.
| | | | | | | | | | | |
Collapse
|
14
|
Shirayama Y, Takahashi S, Minabe Y, Ogino T. In vitro1H NMR spectroscopy shows an increase in N-acetylaspartylglutamate and glutamine content in the hippocampus of amygdaloid-kindled rats. J Neurochem 2005; 92:1317-26. [PMID: 15748151 DOI: 10.1111/j.1471-4159.2004.02958.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We examined energy metabolism and amino acid content in the hippocampus of amygdaloid-kindled rats using (1)H NMR spectroscopy. Three weeks after the last stage 5 seizure, kindled rats were killed by microwave irradiation. The hippocampus was dissected out and subjected to MeOH/CHCl(3) extraction. All (1)H spectra were analyzed to quantify absolute concentrations using a non-linear least squares method, combined with a prior knowledge of chemical shifts. Saturation effects were compensated for by the T1 measurement of each component. Levels of energy metabolism-related compounds, phosphocreatine, creatine, glucose and succinate were the same in both kindled rats and sham controls. Lactate concentration had a tendency to increase, although this was not statistically significant. When compared with sham controls, levels of aspartate, glutamate, glycine and glutamine, as well as GABA and inositol, were increased in the ipsilateral but not the contralateral hippocampus. In contrast, levels of taurine, alanine and threonine were unchanged. Finally, N-acetylaspartylglutamate content was elevated, whereas N-acetyl-l-aspartate content was unaltered in the ipsilateral hippocampus of kindled animals. Our results suggest that amygdala kindling may affects amino acid metabolism, but not energy metabolism.
Collapse
Affiliation(s)
- Yukihiko Shirayama
- Department of Biochemistry and Cellular Biology, National Institute of Neuroscience NCNP, Kodaira, Tokyo, Japan.
| | | | | | | |
Collapse
|
15
|
Cohen-Gadol AA, Pan JW, Kim JH, Spencer DD, Hetherington HH. Mesial temporal lobe epilepsy: a proton magnetic resonance spectroscopy study and a histopathological analysis. J Neurosurg 2004; 101:613-20. [PMID: 15481715 DOI: 10.3171/jns.2004.101.4.0613] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object. Proton magnetic resonance (MR) spectroscopy imaging of the ratio of N-acetylaspartate (NAA) to creatine (Cr) has proved efficacious as a localizing tool in demonstrating the metabolic changes associated with temporal lobe epilepsy. To analyze the significance of these MR spectroscopy findings further, the authors explored the relationship between regional alterations in the NAA/Cr ratio in hippocampi measured preoperatively and histopathological findings in hippocampi resected in patients with intractable mesial temporal lobe epilepsy (MTLE).
Methods. Twelve patients in whom the diagnosis of MTLE had been made and 12 healthy volunteers with no known history of neurological disease underwent high-resolution 1H MR spectroscopy imaging of NAA and Cr (0.64 cm3 nominal voxel resolution) in five voxels spanning the anteroposterior length of the hippocampus. The authors correlated the NAA/Cr ratio with neuropathological findings in resected hippocampi, specifically glial fibrillary acidic protein (GFAP) immunoreactivity and pyramidal neuronal loss. A linear regression analysis of the ipsilateral NAA/Cr ratio revealed a statistically significant relation to the extent of hippocampal neuronal loss in only the CA2 sector (correlation coefficient [r] = −0.66, p < 0.03). The ipsilateral NAA/Cr ratio displayed significant regressions with GFAP immunoreactivity from all the CA sectors (r values ranged from −0.69 and p < 0.01 for the CA4 sector to −0.88 and p < 0.001 for the CA2 sector) except for the CA1. The extent of neuronal cell loss in every hippocampal subfield (r = 0.71−0.74, p < 0.007), except the CA2 (p = 0.08), correlated to the extent of neuronal cell loss in the dentate gyrus. There was no significant relationship between the duration or frequency of seizures and the mean ipsilateral NAA/Cr ratio; however, the mean density of GFAP-immunopositive cells correlated with seizure frequency (p < 0.03).
Conclusions. The NAA/Cr ratio may not measure the full extent of hippocampal neuronal cell loss. The significant association of the NAA/Cr ratio with the GFAP immunoreactivity of most CA sectors indicates that the NAA/Cr ratio may provide a more accurate measurement of recent neuronal injury caused by epileptic activity. The coupling between neuronal impairment and astroglial GFAP expression may indicate the close association between neuronal and glial dysfunction in patients with epilepsy.
Collapse
Affiliation(s)
- Aaron A Cohen-Gadol
- Departments of Neurosurgery and Pathology, Yale University School of Medicine, New Haven, Connecticut, USA.
| | | | | | | | | |
Collapse
|
16
|
Jírů F, Dezortová M, Burian M, Hájek M. The role of relaxation time corrections for the evaluation of long and short echo time 1H MR spectra of the hippocampus by NUMARIS and LCModel techniques. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2003; 16:135-43. [PMID: 14564645 DOI: 10.1007/s10334-003-0018-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2003] [Accepted: 08/20/2003] [Indexed: 10/26/2022]
Abstract
1H MR spectroscopy is routinely used for lateralization of epileptogenic lesions. The present study deals with the role of relaxation time corrections for the quantitative evaluation of long (TE=135 ms) and short echo time (TE=10 ms) 1H MR spectra of the hippocampus using two methods (operator-guided NUMARIS and LCModel programs). Spectra of left and right hippocampi of 14 volunteers and 14 patients with epilepsy were obtained by PRESS (TR/TE=5000/135 ms) and STEAM (TR/TE=5000/10 ms) sequences with a 1.5-T imager. Evaluation was carried out using Siemens NUMARIS software and the results were compared with data from LCModel processing software. No significant differences between the two methods of processing spectra with TE=135 ms were found. The range of relaxation corrections was determined. Metabolite concentrations in hippocampi calculated from spectra with TE=135 ms and 10 ms after application of correction coefficients did not differ in the range of errors and agreed with published data (135 ms/10 ms: NAA=10.2+/-0.6/10.4+/-1.3 mM, Cho=2.4+/-0.1/2.7+/-0.3 mM, Cr=12.2+/-1.3/11.3+/-1.3 mM). When relaxation time corrections were applied, quantitative results from short and long echo time evaluation with LCModel were in agreement. Signal intensity ratios obtained from long echo time spectra by NUMARIS operator-guided processing also agreed with the LCModel results.
Collapse
Affiliation(s)
- Filip Jírů
- MR Unit, ZRIR, Institute for Clinical and Experimental Medicine, Vídenská 1958/9, 140 21, Prague 4, Czech Republic
| | | | | | | |
Collapse
|
17
|
Hammen T, Stefan H, Eberhardt KE, W-Huk BH, Tomandl BF. Clinical applications of 1H-MR spectroscopy in the evaluation of epilepsies--what do pathological spectra stand for with regard to current results and what answers do they give to common clinical questions concerning the treatment of epilepsies? Acta Neurol Scand 2003; 108:223-38. [PMID: 12956855 DOI: 10.1034/j.1600-0404.2003.00152.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Nuclear magnetic resonance spectroscopy (1H-MRS) is a non-invasive method in detecting abnormal spectra of various brain metabolites containing N-acetylaspartate (NAA), Choline (Cho), Creatine (Cr), gamma-Aminobutyric acid (GABA) and Glutamate. Technical processing of the MR-systems, improved automated shimming methods and further development of special shim coils increase the magnetic field homogeneity and lead to a better spectral quality and spectral resolution. The handling of the systems becomes more user-friendly and is more likely to be used in routine diagnostics. The 1H-MRS has become a diagnostic tool for assessing a number of diseases of the central nervous system mainly including epilepsies and brain tumours. The role of 1H-MRS in the assessment of epilepsies will probably increase in future. In the following article, the principles of 1H-MRS and an overview of it in the evaluation and treatment of epilepsies with special regard to temporal lobe epilepsies (TLE) has been illustrated.
Collapse
Affiliation(s)
- T Hammen
- Clinics of Neurology, Center Epilepsy, University of Erlangen-Nuremberg, Erlangen, Germany
| | | | | | | | | |
Collapse
|
18
|
Grabenbauer GG, Reinhold C, Kerling F, Müller RG, Lambrecht U, Pauli E, Ganslandt O, Sauer R, Stefan H. Fractionated stereotactically guided radiotherapy of pharmacoresistant temporal lobe epilepsy. ACTA NEUROCHIRURGICA. SUPPLEMENT 2003; 84:65-70. [PMID: 12379006 DOI: 10.1007/978-3-7091-6117-3_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
PURPOSE This prospective study evaluated the efficacy of fractionated stereotactically guided radiotherapy (SRT) as a treatment of pharmacoresistant temporal lobe epilepsy. PATIENTS AND METHODS Inclusion criteria were patients aged between 17 and 65 years with unilateral temporal focus, without sufficient epilepsy control by antiepileptic drugs or neurosurgery. Two groups of 6 patients each were treated with 21 Gy (7 times 3 Gy) and 30 Gy (15 times 2 Gy). Study end points were change in seizure frequency, intensity, seizure length and neuropsychological parameters. RESULTS All patients experienced a marked reduction in seizure frequency. The mean reduction of seizures was 37% (range 9-77%, i.e. seizures reduced from a monthly mean number of 11.75 to 7.52) at 18 months following radiation treatment and 46% (23-94%, i.e. 0.2-23 seizures per month) during the whole follow-up time. Seizure length was reduced in 5 out of 11 patients and intensity of seizures in 7 out of 11 patients. CONCLUSION Radiotherapy was identified as a safe and effective treatment for pharmacoresistant epilepsy since a good reduction of seizure frequency during longer follow-up was observed. SRT means an appropriate alternative for patients with contraindication against neurosurgery or insufficient seizure reduction after neurosurgery.
Collapse
Affiliation(s)
- G G Grabenbauer
- Department of Radiation Therapy, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Vermathen P, Laxer KD, Schuff N, Matson GB, Weiner MW. Evidence of neuronal injury outside the medial temporal lobe in temporal lobe epilepsy: N-acetylaspartate concentration reductions detected with multisection proton MR spectroscopic imaging--initial experience. Radiology 2003; 226:195-202. [PMID: 12511690 PMCID: PMC2753262 DOI: 10.1148/radiol.2261011668] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To determine whether magnetic resonance (MR) spectroscopic imaging reveals metabolic changes, especially decreased N-acetylaspartate (NAA) concentrations outside the medial temporal lobe in patients with mesial temporal lobe epilepsy (TLE), consistent with neuropathologic findings of extratemporal neuronal impairment. MATERIALS AND METHODS Eleven patients with mesial TLE and 13 control subjects were examined with multisection MR spectroscopic imaging. Three MR spectroscopic imaging sections were acquired. Thirteen brain regions in each hemisphere and the midbrain were analyzed in each patient, and the NAA to creatine-phosphocreatine (Cr) plus choline-containing compounds (Ch) (NAA/[Cr + Ch]) ratios were determined. In addition, hemispheric and whole-brain values were calculated and statistically analyzed. RESULTS The NAA/(Cr + Ch) ratio in the ipsilateral hippocampus was significantly reduced, compared with that in the contralateral hippocampus (P <.002) and compared with that in control subjects (P <.03), confirming findings in previous studies. In patients, whole-brain NAA/(Cr + Ch) ratio outside the hippocampus was significantly lower than that in control subjects (P <.002). For the ipsilateral hemisphere in patients, NAA/(Cr + Ch) ratio was significantly lower than that in control subjects (P <.0002). Comparisons between individual brain regions revealed trends toward lower NAA/(Cr + Ch) ratios in many areas of the ipsilateral and, to a lesser extent, the contralateral hemisphere outside the hippocampus and temporal lobe, suggesting diffuse impairment. CONCLUSION Results suggest that repeated seizure activity damages neurons outside of the seizure focus.
Collapse
Affiliation(s)
- Peter Vermathen
- MR Unit, Department of Veterans Affairs Medical Center, University of California, San Francisco, USA.
| | | | | | | | | |
Collapse
|
20
|
Petroff OAC, Errante LD, Rothman DL, Kim JH, Spencer DD. Neuronal and glial metabolite content of the epileptogenic human hippocampus. Ann Neurol 2002; 52:635-42. [PMID: 12402262 DOI: 10.1002/ana.10360] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Mesial temporal lobe epilepsy is characterized by hippocampal atrophy, hypometabolism, and decreased N-acetylaspartate, often attributed to neuron loss and gliosis. Twenty hippocampal specimens were obtained during temporal lobectomy and frozen quickly. Perchloric acid extracts of the small metabolites were analyzed by proton magnetic resonance spectroscopy. There were no significant associations between hippocampal neuron loss and the cellular content of N-acetylaspartate, glutamate, GABA, glutamine, or aspartate. The mean metabolite content of hippocampi with less than 30% of neurons remaining was the same as those with greater than 65% of neurons surviving. Mean N-acetylaspartate levels were below those reported by in vivo studies of control subjects. The highest and the lowest glutamate concentrations were seen in specimens with the worst neuron loss. A highly significant association between hippocampal N-acetylaspartate and glutamate content was seen with weak associations between N-acetylaspartate and aspartate and glutamate and aspartate. The hippocampal content of N-acetylaspartate, glutamate, GABA, glutamine, and aspartate is altered minimally by severe neuron loss in mesial temporal lobe epilepsy. The epileptic human hippocampus has increased intracellular glutamate content that may contribute to the epileptogenic nature of hippocampal sclerosis.
Collapse
Affiliation(s)
- Ognen A C Petroff
- Department of Neurology, Yale University, 333 Cedar Street, New Haven, CT 06520-8018, USA.
| | | | | | | | | |
Collapse
|
21
|
Guye M, Le Fur Y, Confort-Gouny S, Ranjeva JP, Bartolomei F, Régis J, Raybaud CA, Chauvel P, Cozzone PJ. Metabolic and electrophysiological alterations in subtypes of temporal lobe epilepsy: a combined proton magnetic resonance spectroscopic imaging and depth electrodes study. Epilepsia 2002; 43:1197-209. [PMID: 12366736 DOI: 10.1046/j.1528-1157.2002.05102.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE This study compared the metabolic regional alterations, characterized by proton magnetic spectroscopic imaging ((1)H-MRSI), with electrophysiological abnormalities recorded by using depth electrodes and with structural lesions, in patients with several subtypes of temporal lobe epilepsy (TLE). METHODS Twenty-five subjects were investigated, including 15 controls and 10 patients with drug-resistant unilateral TLE, nine of whom had structural abnormalities identified by MRI. All patients underwent noninvasive presurgical evaluation and then stereoelectroencephalography (SEEG). We performed an original metabolic exploration combining two (1)H-MRS imaging acquisitions associated with two single-voxel acquisitions (temporal poles) to map the most informative regions of interest (ROIs) including mesial and neocortical localizations. The N-acetyl aspartate/(choline+creatine) ratio was chosen as a metabolic index. SEEG analysis allowed the classification of each ROI as electrically normal or abnormal (i.e., involved in ictal and/or interictal discharges). Groups were compared by using a nonparametric Mann-Whitney U test. RESULTS N-Acetyl aspartate/(choline+creatine) was significantly lower in all regions involved in SEEG electrophysiological epileptic abnormalities than in controls (p < 0.05). In contrast, the regions without any electrophysiological abnormalities were not metabolically different from those in controls (p > 0.05) except in one ROI. No differences between the metabolic profiles of epileptogenic and irritative zones were found. The metabolic alterations included, but also extended beyond, the lesions. The presence of metabolic abnormalities in mesial structures was not specific for the mesial subtype and generally extended outside the mesial structures. CONCLUSIONS These results indicate that metabolic abnormalities are linked to ictal and interictal epileptiform activities rather than to structural alterations in TLE.
Collapse
Affiliation(s)
- Maxime Guye
- Service de Neurophysiologie Clinique and Laboratoire de Neurophysiologie et Neuropsychologie, EMI-U INSERM 9926, Marseille, France.
| | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Gadian DG. Magnetic resonance approaches to the identification of focal pathophysiology in children with brain disease. Dev Sci 2002. [DOI: 10.1111/1467-7687.00367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
23
|
Hutchinson PJ, O'Connell MT, Kirkpatrick PJ, Pickard JD. How can we measure substrate, metabolite and neurotransmitter concentrations in the human brain? Physiol Meas 2002; 23:R75-109. [PMID: 12051319 DOI: 10.1088/0967-3334/23/2/202] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Cerebral injury and disease is associated with fundamental derangements in metabolism, with changes in the concentration of important substrates (e.g. glucose), metabolites (e.g. lactate) and neurotransmitters (e.g. glutamate and y-aminobutyric acid) in addition to changes in oxygen utilization. The ability to measure these substances in the human brain is increasing our understanding of the pathophysiology of trauma, stroke, epilepsy and tumours. There are several techniques in clinical practice already in use and new methods are under evaluation. Such techniques include the use of cerebral probes (e.g. microdialysis. voltammetry and spectrophotometry) and functional imaging (e.g. positron emission tomography and magnetic resonance spectroscopy). This review describes these techniques in terms of their principles and clinical applications.
Collapse
Affiliation(s)
- P J Hutchinson
- Department of Neurosurgery and Wolfson Brain Imaging Centre, Addenbrooke's Hospital, University of Cambridge, UK.
| | | | | | | |
Collapse
|
24
|
Affiliation(s)
- Nathaniel A Chuang
- Division of Neuroradiology, Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario, Canada.
| | | | | |
Collapse
|
25
|
Chen JG, Charles HC, Barboriak DP, Doraiswamy PM. Magnetic resonance spectroscopy in Alzheimer's disease: focus on N-acetylaspartate. ACTA NEUROLOGICA SCANDINAVICA. SUPPLEMENTUM 2001; 176:20-6. [PMID: 11261801 DOI: 10.1034/j.1600-0404.2000.00303.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This paper reviews published post-mortem brain and in-vivo proton magnetic resonance spectroscopy (1H-MRS) studies in Alzheimer's disease (AD) and focuses on the emerging role of N-acetylaspartate (NAA) as a prognostic marker of neuronal function. Post-mortem brain studies have reported significantly lower NAA levels in AD brains than in control brains, and some have correlated the low levels with neuropathological findings (i.e. amyloid plaques and neurofibrillary tangles). Similarly, almost all published in-vivo studies have reported lower NAA levels in AD patients compared to elderly controls. While some studies have found changes in metabolite levels that were considered useful for the diagnosis of AD, most have found that 1H-MRS provided little or no advantages over other, more common diagnostic tools. Instead, recent studies in AD and other neuropsychiatric disorders suggest that NAA may be more useful as a prognostic marker for monitoring neurodegeneration, stabilization, or improvement, and for evaluating therapeutic response to novel drugs.
Collapse
Affiliation(s)
- J G Chen
- Department of Psychiatry, Duke University of Medical Center, Durham, NC 27710, USA
| | | | | | | |
Collapse
|
26
|
Abstract
In vivo magnetic resonance spectroscopy (MRS) addresses metabolic pathways and their steady states in different tissue types. The brain has by tradition, and due to technical limitations in other organs, been one of the tissues most studied by MRS, and both 1H- and 31P-MRS have been used. Although 31P-MRS is outstanding for the evaluation of sources of metabolic energy in the brain, 1H-MRS has become the major clinically applied method in neurospectroscopy, as it provides information on markers of neuronal function, myelin, cell membranes, and metabolic active compounds. Furthermore, MR sensitivity is much greater for protons than it is for phosphorus and 1H-MRS, therefore allowing better spatial resolution. This review focuses on neurospectroscopy and diagnostic insights into diverse neurological problems provided by 1H-MRS applied as a clinical tool.
Collapse
Affiliation(s)
- I M Burtscher
- Department of Diagnostic Radiology, University Hospital Lund, Lund, Sweden.
| | | |
Collapse
|
27
|
Richardson MP. CPD - education and self-assessment: functional imaging in epilepsy. Seizure 2001; 10:139-56. [PMID: 11407959 DOI: 10.1053/seiz.2001.0546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Functional imaging plays a growing role in the clinical assessment and research investigation of patients with epilepsy. This article reviews the literature on functional MRI (fMRI) investigation of EEG activity, fMRI evaluation of cognitive and motor functions, magnetic resonance spectroscopy (MRS), single photon emission computed tomography (SPECT) and positron emission tomography (PET) in epilepsy. The place of these techniques in clinical evaluation and their contribution to a better neurobiological understanding of epilepsy are discussed.
Collapse
Affiliation(s)
- M P Richardson
- Medical Research Council Fellow, Institute of Neurology, University College London, UK.
| |
Collapse
|
28
|
Hsu YY, Chen MC, Lim KE, Chang C. Reproducibility of hippocampal single-Voxel proton MR spectroscopy and chemical shift imaging. AJR Am J Roentgenol 2001; 176:529-36. [PMID: 11159110 DOI: 10.2214/ajr.176.2.1760529] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE We investigated between- and within-acquisition reproducibility of hippocampal metabolite ratios obtained using automated proton MR spectroscopy. SUBJECTS AND METHODS We examined 30 healthy adults with a 1.5-T scanner four times on 3 days using single-voxel spectroscopy over the left hippocampus, chemical shift imaging over the left hippocampus, and chemical shift imaging over the bilateral hippocampi. Metabolite ratios were derived from the integral values of three major peaks: N:-acetylaspartate (NAA), choline-containing compounds (Cho), and creatine plus phosphocreatine (Cr). The random-effects model of one-way analysis of variance was used to evaluate the reproducibility in terms of coefficient of variation; the mixed-effects model was used to compare the results of different hippocampal regions and spectroscopic techniques. RESULTS Most coefficients of variation for the NAA/(Cho+Cr) ratio were less than 20%. All the coefficients of variation for the posterior hippocampus (15-25%) were less than those for the anterior hippocampus (20-44%). The posterior hippocampal NAA/(Cho+Cr) ratio of unilateral chemical shift imaging had the lowest coefficient of variation (<16%). Single-voxel spectroscopy and unilateral chemical shift imaging had similar coefficients of variation for the anterior hippocampal NAA/(Cho+Cr) ratios (17-20%). There was a significant difference in metabolite ratios measured in different hippocampal regions (p<0.01) and in those acquired with different spectroscopic techniques (p<0.001). CONCLUSION The NAA/(Cho+Cr) ratio is the most reproducible parameter for hippocampal MR spectroscopy on a 1.5-T scanner. Regional variation and technical differences in metabolite ratios must be considered when interpreting proton spectra of the hippocampus.
Collapse
Affiliation(s)
- Y Y Hsu
- Department of Radiology, Chang Gung Memorial Hospital, 199 Tun-Hwa North Rd., Taipei, Taiwan 105, ROC
| | | | | | | |
Collapse
|
29
|
Stefan H, Feichtinger M, Pauli E, Schäfer I, Eberhardt KW, Kasper BS, Hopp P, Buchfelder M, Huk J, Paulus W. Magnetic resonance spectroscopy and histopathological findings in temporal lobe epilepsy. Epilepsia 2001; 42:41-6. [PMID: 11207783 DOI: 10.1046/j.1528-1157.2001.080873.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE In some patients with temporal lobe epilepsy, histopathological evaluation of resected brain tissue after surgical treatment may reveal several features indicative of discrete cortical malformations. We sought to determine whether these histopathological features were accompanied by hippocampal changes detectable preoperatively by proton magnetic resonance (MR) spectroscopy and to evaluate their relationship with postoperative outcome. METHODS In 25 consecutive temporal lobe epilepsy patients who were scheduled for surgical treatment, MR spectroscopy was performed, and resected brain tissue was analyzed histopathologically for the presence of discrete cortical malformations (e.g., microdysgenesis). Outcome was assessed in all patients with an average postoperative period of 26 months. RESULTS In 13 patients, we found subtle, histopathologically detectable signs of cortical malformation: 6 of them with concomitant hippocampal sclerosis (dual pathology) and 7 without. The latter subgroup had a worse surgical outcome and showed enhanced bilateral and/or contralateral pathological changes in the hippocampal formation when investigated by MR spectroscopy. CONCLUSIONS These data suggest that by showing contralaterally or bilaterally abnormal spectra, MR spectroscopy might be able to indicate pathological changes in subtle developmental disorders that are possibly more widespread over the brain. This observation may improve noninvasive diagnosis in presurgical evaluation and the neurobiological understanding of cortical malformations in pharmacoresistant temporal lobe epilepsy.
Collapse
Affiliation(s)
- H Stefan
- Department of Neurology, University Erlangen-Nürnberg, Schwabachanlange 6, 90154 Erlangen, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Eberhardt KE, Stefan H, Buchfelder M, Pauli E, Hopp P, Huk W, Tomandl BF. The significance of bilateral CSI changes for the postoperative outcome in temporal lobe epilepsy. J Comput Assist Tomogr 2000; 24:919-26. [PMID: 11105713 DOI: 10.1097/00004728-200011000-00019] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE In a prospective study, we evaluated the significance of preoperative bilateral chemical shift spectroscopy imaging (CSI) changes for the prognosis of postoperative seizure outcome in the surgical treatment of patients with temporal lobe epilepsy (TLE). METHOD CSI using multivoxel spectroscopy was performed. Twenty-six consecutive TLE patients scheduled for epilepsy surgery were included. To evaluate the value of the CSI with respect to postoperative seizure outcome, discriminant analysis with ipsilateral and contralateral CSI was performed. RESULTS The discriminant analysis showed that the contralateral metabolic changes alone are able to predict seizure outcome whereby 92.3% of cases were correctly classified. Upon comparison of the two groups of seizure-free and non-seizure-free patients with respect to contralateral metabolic changes, the difference proved to be highly significant (paired t test: t = -6.3, df = 24, p < 0.001). CONCLUSION Bilateral metabolic CSI changes have a predictive value for the postoperative outcome in patients with TLE. In patients with severe bilateral metabolic changes, poor seizure outcome is a likely result.
Collapse
Affiliation(s)
- K E Eberhardt
- Department of Neurosurgery, University of Erlangen-Nuremberg, Germany.
| | | | | | | | | | | | | |
Collapse
|
31
|
Abstract
Temporal lobe epilepsy (TLE) is the most common type of medically intractable partial epilepsy amenable to surgery. In the majority of cases, the underlying pathology in temporal lobe epilepsy is mesial temporal sclerosis (MTS). Whereas historically invasive recordings were required for most epilepsy surgeries, indications have dramatically changed since the introduction of high-resolution MRI, which uncovers structural lesions in a high percentage of cases. No invasive recordings are required to perform a temporal lobectomy in patients with intractable epilepsy who have structural imaging suggesting unilateral MTS and concordant interictal and ictal surface EEG recordings, functional imaging, and clinical findings. Invasive testing is needed if there is evidence of bitemporal MTS on structural imaging and/or electrophysiologically, and additional information from functional imaging, neuropsychology, and the intracarotid amobarbital (Wada) test also does not help to lateralize the epileptogenic zone. Depth electrodes can be particularly helpful in this setting. However, no surgery is indicated, even without invasive recordings, if bitemporal-independent seizures are recorded by surface EEG and all additional testing is inconclusive. Other etiologies of TLE such as a tumor, vascular malformation, encephalomalacia, or congenital developmental abnormality account for about 30% of all patients who undergo epilepsy surgery. Epilepsy surgery is indicated after limited electrophysiologic investigations if neuroimaging and electrophysiology converge. However, approaches for resection in lesional temporal lobe epilepsy vary among centers. Completeness of resection is crucial and invasive recordings may be needed to guide the resection by mapping eloquent cortex and/or to determine the extent of the non-MRI-visible epileptogenic area. Specific approaches for the different pathologies are discussed because there is evidence that the relationship between the lesions visible on MRI and the epileptogenic zone varies among lesions of different pathologies, and therefore variable surgical strategies must be applied.
Collapse
Affiliation(s)
- B Diehl
- The Cleveland Clinic Foundation, Department of Neurology, Ohio 44195, USA
| | | |
Collapse
|
32
|
Stanley JA, Pettegrew JW, Keshavan MS. Magnetic resonance spectroscopy in schizophrenia: methodological issues and findings--part I. Biol Psychiatry 2000; 48:357-68. [PMID: 10978719 DOI: 10.1016/s0006-3223(00)00949-5] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Our knowledge of the biological basis of schizophrenia has significantly increased with the contribution of in vivo proton and phosphorus magnetic resonance spectroscopy (MRS), a noninvasive tool that can assess the biochemistry from a localized region in the human body. Studies thus far suggest altered membrane phospholipid metabolism at the early stage of illness and reduced N-acetylaspartate, a measure of neuronal volume/viability in chronic schizophrenia. Inconsistencies remain in the literature, in part due to the complexities in the MRS methodology. These complexities of in vivo spectroscopy make it important to understand the issues surrounding the design of spectroscopy protocols to best address hypotheses of interest. This review addresses these issues, including 1) understanding biochemistry and the physiologic significance of metabolites; 2) the influence of acquisition parameters combined with spin-spin and spin-lattice relaxation effects on the MRS signal; 3) the composition of spectral peaks and the degree of overlapping peaks, including the broader underlying peaks; 4) factors affecting the signal-to-noise ratio; 5) the various types of localization schemes; and 6) the objectives to produce accurate and reproducible quantification results. The ability to fully exploit the potentials of in vivo spectroscopy should lead to a protocol best optimized to address the hypotheses of interest.
Collapse
Affiliation(s)
- J A Stanley
- Neurophysics Laboratory, Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | | | | |
Collapse
|
33
|
Li LM, Cendes F, Andermann F, Dubeau F, Arnold DL. Spatial extent of neuronal metabolic dysfunction measured by proton MR spectroscopic imaging in patients with localization-related epilepsy. Epilepsia 2000; 41:666-74. [PMID: 10840397 DOI: 10.1111/j.1528-1157.2000.tb00226.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To assess the spatial extent of the decrease in the neuronal marker N-acetyl-aspartate (NAA) relative to creatine (Cr) in patients with localization-related epilepsy, and to assess clinical differences between patients with and without widespread NAA/Cr reduction. METHODS We studied 51 patients with localization-related epilepsy. Patients were divided into three groups according to the EEG investigation: (a) temporal lobe epilepsy (TLE, n = 21), (b) extratemporal lobe epilepsy (extra-TLE, n = 20), and (c) multilobar epilepsy (patients with a wider epileptogenic zone, n = 10). We acquired proton magnetic resonance (MR) spectrocopic imaging (1H-MRSI) of temporal and frontocentroparietal regions in separate examinations for both patients and controls. NAA/Cr values 2 standard deviations below the mean of normal controls were considered abnormal. RESULTS Twenty-three (45%) patients including 12 with TLE had normal MR imaging including volumetric studies of the hippocampus. Forty-nine (96%) patients had low NAA/Cr, indicating neuronal dysfunction in either temporal and/or extratemporal 1H-MRSIs; 38% of patients with TLE and 50% of patients with extra-TLE also had NAA/Cr reduction outside the clinical and EEG-defined primary epileptogenic area. The NAA/Cr reduction was more often widespread in the multilobar group [six (60%) of 10] than in temporal or extratemporal groups [five (31%) of 16]. Nonparametric tests of (a) seizure duration, (b) seizure frequency, and (c) lifetime estimated seizures showed no statistically significant difference (p > 0.05) for TLE and extra-TLE patients with or without NAA/Cr reduction outside the seizure focus. CONCLUSIONS Of patients with localization-related epilepsy, 40-50% have neuronal metabolic dysfunction that extends beyond the epileptogenic zone defined by clinical-EEG and/or the structural abnormality defined by MRI.
Collapse
Affiliation(s)
- L M Li
- Department of Neurology and Neurosurgery & the Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | | | | | | | | |
Collapse
|
34
|
Someya Y, Obata T, Suhara T, Ota Y, Ikehira H, Tanada S, Hirakawa K, Okubo Y, Sasaki Y. Seizure frequency and bilateral temporal abnormalities: a proton magnetic resonance spectroscopy of temporal lobe epilepsy. Seizure 2000; 9:274-9. [PMID: 10880288 DOI: 10.1053/seiz.2000.0396] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Proton magnetic resonance spectroscopy ((1)H-MRS) was performed in seven healthy volunteers and 17 patients with temporal lobe epilepsy (TLE) to clarify the correlation of the severity of epilepsy with bilateral temporal changes in N-acetylaspartate (NAA), choline-containing compounds (Cho) and creatine + phosphocreatine (Cr). Despite unilateral EEG focus, bilateral temporal reduction in NAA /(Cho + Cr) was revealed in patients with intractable seizures. The potential for seizure generation correlated with the NAA /(Cho + Cr) reduction not only on the ipsilateral side but also on the contralateral side. Proton MRS proved to be a useful measurement for obtaining important information about the neuronal changes as well as the lateralization of the epileptogenic focus in TLE patients.
Collapse
Affiliation(s)
- Y Someya
- Section of Psychiatry and Behavioral Science, Tokyo Medical and Dental University School of Medicine, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Pauli E, Eberhardt KW, Schäfer I, Tomandl B, Huk WJ, Stefan H. Chemical shift imaging spectroscopy and memory function in temporal lobe epilepsy. Epilepsia 2000; 41:282-9. [PMID: 10714399 DOI: 10.1111/j.1528-1157.2000.tb00157.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE Hippocampal neuron loss and associated memory deficits are characteristic of intractable temporal lobe epilepsy (TLE). Proton chemical shift imaging (CSI) spectroscopy is a sensitive tool for detecting neuronal loss. The aim of this study was to investigate the correlation between memory functions and results provided by CSI spectroscopy of the hippocampal structures. METHODS Ten patients with cryptogenic TLE participated. The study protocol involved both the acquisition of high-spatial-resolution CSI spectroscopy and neuropsychological evaluation, including memory testing and intracarotid sodium amytal test (IAT). The analysis of the CSI data was based on normative data obtained in 30 healthy volunteers. Memory functions were represented by verbal, visual, and general memory indices. RESULTS A significant correlation was found between CSI spectroscopy of the hippocampal formation and the verbal memory indices for the dominant hemisphere. In addition, there was a significant correspondence of the qualitative judgment "hippocampal pathology indicated by CSI spectroscopy" and both "material specific memory deficit" and "memory deficit in the IAT." CONCLUSIONS Our results demonstrate that CSI spectroscopy of the hippocampal structures is strongly related to lateralized memory deficits in patients with TLE. This suggests that CSI spectroscopy may be useful in the prediction of postoperative outcome in respect of seizure control and memory.
Collapse
Affiliation(s)
- E Pauli
- Department of Neurology, University of Erlangen-Nuernberg, Germany
| | | | | | | | | | | |
Collapse
|
36
|
Chang KH, Kim HD, Park SW, Song IC, Yu IK, Han MH, Lee SK, Chung CK, Park YH. Usefulness of single voxel proton MR spectroscopy in the evaluation of hippocampal sclerosis. Korean J Radiol 2000; 1:25-32. [PMID: 11752925 PMCID: PMC2718133 DOI: 10.3348/kjr.2000.1.1.25] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE The purpose of our study was to determine the ability of H-1 MR spectroscopy (MRS) to lateralize the lesion in patients with hippocampal sclerosis. MATERIALS AND METHODS Twenty healthy volunteers and 25 patients with intractable temporal lobe epilepsy whose MR imaging diagnosis was unilateral hippocampal sclerosis were included. This diagnosis was based on the presence of unilateral atrophy and/or high T2 signal intensity of the hippocampus. Singlevoxel H-1 MRS was carried out on a 1.5-T unit using PRESS sequence (TE, 136 msec). Spectra were obtained from hippocampal areas bilaterally with volumes of interest (VOIs) of 6.0 cm(3) and 2.25 cm(3) in healthy volunteers, and of either 6.0 cm(3) (n = 14) or 2.25 cm(3) (n = 11) in patients. Metabolite ratios of NAA/Cho and NAA/Cr were calculated from relative peak height measurements. The capability of MRS to lateralize the lesion and to detect bilateral abnormalities was compared with MR imaging diagnosis as a standard of reference. RESULTS In healthy volunteers, NAA/Cho and NAA/Cr ratios were greater than 0.8 and 1.0, respectively. In patients, the mean values of these ratios were significantly lower on the lesion side than on the contralateral side, and lower than those of healthy volunteers (p <.05). The overall correct lateralization rate of MRS was 72% (18/25); this rate was lower with a VOI of 6.0 cm(3) than of 2.25 cm(3) (64% versus 82%, p <.05). Bilateral abnormalities on MRS were found in 24% (6/25) of cases. CONCLUSION Although its rate of correct lateralization is low, single-voxel H-1 MRS is a useful and promising diagnostic tool in the evaluation of hippocampal sclerosis, particularly for the detection of bilateral abnormalities. To improve the diagnostic accuracy of H-1 MRS, further investigation, including the use of a smaller VOI and measurement of the absolute amount of metabolites, are needed.
Collapse
Affiliation(s)
- K H Chang
- Department of Radiology, Seoul National University College of Medicine, Seoul, Korea.
| | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Meiners LC, van der Grond J, van Rijen PC, Springorum R, de Kort GA, Jansen GH. Proton magnetic resonance spectroscopy of temporal lobe white matter in patients with histologically proven hippocampal sclerosis. J Magn Reson Imaging 2000; 11:25-31. [PMID: 10676617 DOI: 10.1002/(sici)1522-2586(200001)11:1<25::aid-jmri4>3.0.co;2-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The purpose of this study was to assess temporal lobe white matter changes accompanying hippocampal sclerosis on magnetic resonance (MR) imaging using single-voxel 1H MR spectroscopy and to strengthen the hypothesis that these white matter changes are caused by myelin alterations. In 11 patients with histologically proven hippocampal sclerosis, preoperative coronal fluid-attenuated inversion recovery images were visually assessed by two experienced neuroradiologists for hippocampal signal increase and size decrease, atrophy of collateral white matter, and temporal lobe gray/white matter demarcation loss. Single-voxel 1H MR spectroscopy of the white matter of each anterior temporal lobe was also performed, excluding the amygdala and hippocampus. The N-acetyl-aspartate (NAA)/choline and NAA/creatine ratios were calculated. In 12 healthy volunteers both temporal lobes were spectroscopically examined. In all patients the excised hippocampi were histologically assessed for the presence of sclerosis, and the excised neocortical temporal lobes were examined for gray and white matter abnormalities. MRI abnormalities were found on the right in six patients, on the left in four, and one scan was normal. Hippocampal signal increase was seen in nine patients, hippocampal size decrease in ten, atrophy of collateral white matter in nine, and gray/white matter demarcation loss in six. A significant decrease in the NAA/choline ratio was found in temporal lobe white matter ipsilateral to the pathologic hippocampus (symptomatic side), compared with the contralateral, asymptomatic side (P < 0.01), and also compared with controls (P < 0.001). The ipsilateral NAA/creatine ratio was also significantly decreased (P < 0.05) compared with the contralateral side and the control subjects (P < 0.001). Histological examination showed hippocampal sclerosis to a different degree in all patients. Neither gliosis nor cortical dysplasia was found in the ipsilateral, symptomatic temporal lobe. Significant decrease in the mean of NAA/choline ratios is found in temporal lobe white matter of patients with histologically confirmed hippocampal sclerosis. As this indicates neuronal loss or dysfunction, the number of axons may be reduced, with associated decrease in myelin density.
Collapse
Affiliation(s)
- L C Meiners
- Department of Radiology, University Hospital Utrecht, The Netherlands
| | | | | | | | | | | |
Collapse
|
38
|
Seymour KJ, Bluml S, Sutherling J, Sutherling W, Ross BD. Identification of cerebral acetone by 1H-MRS in patients with epilepsy controlled by ketogenic diet. MAGMA (NEW YORK, N.Y.) 1999; 8:33-42. [PMID: 10383091 DOI: 10.1007/bf02590633] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Ketogenic diet (KD) is highly effective in controlling epileptic seizures in children. One of the mechanisms postulated, the accumulation of ketone bodies, acetoacetate (AcAc) and/or betahydroxybutyrate (beta-OHB) in the brain, would be detectable by non-invasive proton magnetic resonance spectroscopy (1H-MRS). 1H-MRS was performed in occipital cortical grey matter in 14 epileptics (E); ages 3.8-48.3 years), seven KD and seven without, and 16 healthy age-matched subjects. One E was examined before and after KD. A singlet resonance (sigma = 2.22 ppm), distinct from AcAc (sigma = 2.26 and 3.46 ppm), and identified as acetone was present in all spectra of children on KD (nine spectra in five children; concentration 0.7 +/- 0.2 mM). This resonance was absent from Control and E without diet. AcAc and beta-OHB, which were not detectable in KD brain, were found in urine or blood of all KD. Seizures were well controlled in all E in whom acetone was detected. Two of seven E, both adults, were seizure-free without detectable acetone. Cerebral acetone may contribute to seizure control in KD, but is unlikely to be the sole mechanism.
Collapse
Affiliation(s)
- K J Seymour
- Huntington Medical Research Institutes, Pasadena, CA 91105, USA
| | | | | | | | | |
Collapse
|
39
|
Hájek M, Dezortová M, Komárek V. 1H MR spectroscopy in patients with mesial temporal epilepsy. MAGMA (NEW YORK, N.Y.) 1998; 7:95-114. [PMID: 9951770 DOI: 10.1007/bf02592234] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The study provides a review of the basic examination procedures and results of proton magnetic resonance spectroscopy (1H MRS) in patients suffering from mesial temporal lobe epilepsy (MTLE). The source of seizures in MTLE is most often an epileptogenic focus secondary to hippocampal sclerosis. 1H MRS currently plays an important role in the non-invasive diagnosis of this type of epileptogenic lesion. The decisive 1H MRS parameter characterizing an epileptogenic lesion is a statistically significantly decreased value of N-acetylaspartate levels compared with control values, most often associated with a decrease in the ratios of the intensities of NAA/Cr, NAA/Cho and NAA/(Cr + Cho) signals. Moreover, MRS makes it possible to distinguish bilateral involvement of mesial temporal structures typically associated with a bilateral decrease in the levels of metabolites and/or their ratios. As regards other metabolic compounds which play an important role in the pathobiochemistry of epilepsy, MRS is employed to study the action of gamma-aminobutyric acid (GABA), inositol, lactate, glutamine, and glutamate, the clinical function of which has not been fully clarified as yet. It is in this context that one should consider the application of 1H MRS in evaluating the action of some new anti-epileptic agents affecting excitatory and inhibitory amino acids. There is no doubt that in vivo 1H MRS, along with other imaging methods, has made a significant contribution to the clinical and biochemical description of epileptic seizures and has assumed a prominent position among the techniques of pre-operative examination in epileptic surgery.
Collapse
Affiliation(s)
- M Hájek
- Magnetic Resonance Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
| | | | | |
Collapse
|
40
|
Mendes-Ribeiro JA, Soares R, Simões-Ribeiro F, Guimarães ML. Reduction in temporal N-acetylaspartate and creatine (or choline) ratio in temporal lobe epilepsy: does this 1H-magnetic resonance spectroscopy finding mean poor seizure control? J Neurol Neurosurg Psychiatry 1998; 65:518-22. [PMID: 9771777 PMCID: PMC2170285 DOI: 10.1136/jnnp.65.4.518] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Proton magnetic resonance spectroscopy (1H-MRS) is a potentially useful tool in the in vivo investigation of brain metabolites in intractable temporal lobe epilepsy (TLE). Focal N-acetylaspartate (NAA) reductions have been correlated with mesial temporal sclerosis (MTS) in surgically resected epileptogenic foci. OBJECTIVE To evaluate the abnormalities in the metabolites NAA, creatine+ phosphocreatine (Cr), and choline containing compounds (Cho) in the temporal lobe of medically refractory patients with temporal lobe epilepsy, seizure free patients with temporal lobe epilepsy, and normal controls. PATIENTS AND METHODS Ten refractory patients, 12 seizure free patients with temporal lobe epilepsy, and 10 age matched normal controls were studied by 1H-magnetic resonance spectroscopy. All patients had consistently unilateral temporal EEG abnormalities and a normal brain MRI. Proton MR spectra were obtained from an 8 ml volume in the medial temporal lobes in patients with temporal lobe epilepsy (ipsilateral to EEG foci) and the normal controls. The signals measured were expressed in terms of NAA/Cr, NAA/Cho, and Cho/Cr. RESULTS When compared with seizure free patients with temporal lobe epilepsy and normal controls, the 10 refractory patients with temporal lobe epilepsy had a lower mean (SEM) NAA/Cr ratio (1.65 (0.53) v 2.62 (0.60), and 2.66 (0.73); p<0.002 and p<0.006) and a lower mean NAA/Cho ratio (1.59 (0.79) v 2.83 (1.33) and 2.58 (0.67); p<0.02 and p<0.007). Furthermore, the two patients showing the lowest NAA/Cr ratios (1.47 and 1.73) in the seizure free group had had a past period of poor seizure control. CONCLUSIONS There were reduced temporal NAA/Cr and NAA/Cho ratios, suggesting neuronal loss or damage, associated with past or present poor seizure control in the patients with temporal lobe epilepsy, but it does not exclude the possibility of a future complete seizure control (seizure free patients with temporal lobe epilepsy at the time of 1H-MRS). This study warrants further 1H-MRS investigation with a larger series of patients with temporal lobe epilepsy.
Collapse
|
41
|
Abstract
Surgical treatment is a well established option for patients with medically refractory temporal lobe epilepsy. Magnetic resonance imaging (MRI) has revolutionized the evaluation of these patients. New techniques can identify structural, metabolic and functional abnormalities associated with the epileptogenic zone. Mesial temporal sclerosis is the most common pathological finding and presents as hippocampal atrophy, which can be detected by visual inspection in most cases. Volumetric analysis of medial temporal structures offers the advantage of detecting bilateral abnormalities. Magnetic resonance spectroscopy can detect metabolic abnormalities associated with the epileptogenic focus. Functional MRI allows for the non-invasive evaluation of cognitive function, allowing for the localization of the neuroanatomic substrate of motor, sensory and cognitive functions. Intraoperative MRI-based image guided systems are a useful adjunct in the surgical treatment of this epileptic syndrome.
Collapse
Affiliation(s)
- D King
- Department of Neurology, University of Pennsylvania Medical Center, Philadelphia 19104, USA
| | | |
Collapse
|
42
|
Bertolino A, Callicott JH, Elman I, Mattay VS, Tedeschi G, Frank JA, Breier A, Weinberger DR. Regionally specific neuronal pathology in untreated patients with schizophrenia: a proton magnetic resonance spectroscopic imaging study. Biol Psychiatry 1998; 43:641-8. [PMID: 9582997 DOI: 10.1016/s0006-3223(97)00555-6] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Proton magnetic resonance spectroscopic imaging (1H-MRSI) studies have reported reductions of N-acetyl aspartate (NAA), a marker of neuronal integrity, in the hippocampal region (HIPPO) and dorsolateral prefrontal cortex (DLPFC) of pharmacologically treated patients with schizophrenia. The purpose of the present study was twofold: to exclude drug treatment as a source of the previous findings and to examine NAA relative concentrations in a unique sample of chronically untreated patients. METHODS We studied 12 medication-free patients, 5 of whom were "drug naive" and symptomatic for a mean of 12 years, and 12 control subjects. Ratios of areas under the metabolite peaks of the proton spectra were determined [i.e., NAA/creatine (CRE), NAA/choline (CHO), CHO/CRE] for multiple cortical and subcortical regions. Hippocampal formation and frontal lobe volumes were also measured to test for correlations with 1H-MRSI data. RESULTS Significant reductions of NAA/CRE and NAA/CHO were found bilaterally in HIPPO and DLPFC. There were no significant changes in CHO/CRE or in NAA ratios in any other area sampled. No significant correlation was found between metabolite ratios, length of illness, and volumes of the hippocampal region and frontal lobe. Mean ratios and effect sizes were not different in chronically ill but still medication-naive patients in comparison with subacute patients and previously studied chronic patients receiving medications. CONCLUSIONS Bilateral reductions of NAA ratios in HIPPO and DLPFC are reliable findings. The findings implicate a relatively localized pattern of neurochemical pathology that does not appear to change with prolonged illness whether medicated or unmedicated.
Collapse
Affiliation(s)
- A Bertolino
- Clinical Brain Disorders Branch, National Institute of Mental Health, NIH, Neurosciences Center at Saint Elizabeths, Washington, DC 20032, USA
| | | | | | | | | | | | | | | |
Collapse
|
43
|
Abstract
Neuroimaging techniques have improved the understanding, diagnosis, and management of epilepsy. By providing excellent structural information, MRI is the technique of choice in evaluating patients with epilepsy. Functional imaging techniques, including MR spectroscopy, functional MRI, positron emission tomography, and single photon emission CT, permit noninvasive assessment of the epileptic substrate, its functional status, and neuroreceptors. The MRI-based techniques will potentially assume a greater role in the cost-effective workup of the patient. Currently, newer techniques such as magnetoencephalography, magnetic source imaging, and optical imaging are research tools.
Collapse
Affiliation(s)
- Y Y Sitoh
- Department of Diagnostic Imaging, Tan Tock Seng Hospital, Singapore
| | | |
Collapse
|
44
|
Stanley JA, Cendes F, Dubeau F, Andermann F, Arnold DL. Proton magnetic resonance spectroscopic imaging in patients with extratemporal epilepsy. Epilepsia 1998; 39:267-73. [PMID: 9578043 DOI: 10.1111/j.1528-1157.1998.tb01371.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE Reduced levels of N-acetylaspartate (NAA) in temporal lobes responsible for temporal lobe epilepsy have been observed consistently in proton magnetic resonance spectroscopy (MRS) studies. METHODS We investigated the potential of proton MRS to detect low NAA outside of the temporal lobes in patients with non-lesional partial extratemporal epilepsy. Proton MR spectroscopic imaging (MRSI) data of both frontal lobes and central/postcentral regions were obtained in 20 such patients and 16 normal control subjects. The epileptogenic region was determined by an extensive clinical-EEG investigation, including the recording of habitual seizures in each patient, and intracranial EEG recordings in 10 patients. RESULTS The relative NAA resonance intensities (i.e., NAA/phosphocreatine plus creatine (CR(t)), NAA/choline-containing metabolites (Cho(t)) and NAA/Cr(t) + Cho(t)), were all significantly reduced throughout the spectroscopic image as compared with that of the controls. Furthermore, reduction of the NAA ratios was greater in the epileptogenic region as compared with the nonepileptogenic regions, on EEG investigation. CONCLUSIONS In vivo proton MRSI of patients with nonlesional partial extratemporal epilepsy detected evidence of widespread neuronal damage or dysfunction that was greatest in the region of seizure focus.
Collapse
Affiliation(s)
- J A Stanley
- Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | | | | | | | | |
Collapse
|
45
|
Thompson JE, Castillo M, Kwock L. MR SPECTROSCOPY IN THE EVALUATION OF EPILEPSY. Magn Reson Imaging Clin N Am 1998. [DOI: 10.1016/s1064-9689(21)00442-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
46
|
Knowlton RC, Laxer KD, Ende G, Hawkins RA, Wong ST, Matson GB, Rowley HA, Fein G, Weiner MW. Presurgical multimodality neuroimaging in electroencephalographic lateralized temporal lobe epilepsy. Ann Neurol 1997; 42:829-37. [PMID: 9403474 PMCID: PMC2709486 DOI: 10.1002/ana.410420603] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The purpose of this study was to compare 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET), hippocampal volumetry (HV), T2 relaxometry, and proton magnetic resonance spectroscopic imaging (1H-MRSI) in the presurgical neuroimaging lateralization of patients with nonlesional, electroencephalogram (EEG)-defined unilateral temporal lobe epilepsy (TLE). Twenty-five patients were prospectively studied, along with age-matched controls. T2 relaxometry examinations were performed in 13 patients. Comparison of FDG-PET, HV, and 1H-MRSI was possible in 23 patients. FDG-PET lateralized 87% of patients, HV 65%, N-acetyl aspartate (NAA)/(choline [Cho] + creatine [Cr]) 61%, and [NAA] 57%. Combined HV and NAA/(Cho + Cr) results lateralized 83% of the patients, a value similar to PET. Of 10 patients with normal magnetic resonance imaging (MRI) scans, 2 were lateralized with HV, 6 with FDG-PET, 4 with NAA/(Cho + Cr), and 3 with [NAA]. T2 relaxometry lateralized no patients without hippocampal atrophy. Bilateral abnormality was present in 29 to 33% of patients with 1H-MRSI measures and 17% with HV. Only hippocampal atrophy correlated with postoperative seizure-free outcome. FDG-PET remains the most sensitive imaging method to correlate with EEG-lateralized TLE. Both FDG-PET and 1H-MRSI can lateralize patients with normal MRI, but only the presence of relative unilateral hippocampal atrophy is predictive of seizure-free outcome. Bilaterally abnormal MRI and 1H-MRSI measures do not preclude good surgical outcome.
Collapse
Affiliation(s)
- R C Knowlton
- Department of Neurology, University of California, San Francisco, School of Medicine, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
47
|
|
48
|
Vermathen P, Ende G, Laxer KD, Knowlton RC, Matson GB, Weiner MW. Hippocampal N-acetylaspartate in neocortical epilepsy and mesial temporal lobe epilepsy. Ann Neurol 1997; 42:194-9. [PMID: 9266729 PMCID: PMC2744690 DOI: 10.1002/ana.410420210] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Previous magnetic resonance spectroscopy (MRS) studies have shown that N-acetylaspartate (NAA) is reduced not only in the ipsilateral but also in the contralateral hippocampus of many patients with mesial temporal lobe epilepsy (mTLE). The reason for the contralateral damage is not clear. To test whether the hippocampus is also damaged if the focus is outside the hippocampus, we have measured patients with neocortical epilepsy (NE). Therefore, the goals of this study were to determine if hippocampal NAA is reduced in NE and if hippocampal NAA discriminates NE from mTLE. MRS imaging (MRSI) studies were performed on 10 NE patients and compared with MRSI results in 23 unilateral mTLE patients and 16 controls. The results show that, in contrast to mTLE, NAA was not reduced in the hippocampus of NE patients, neither ipsilateral nor contralateral to the seizure focus. These results suggest that repeated seizures do not cause secondary damage to the hippocampus. The absence of spectroscopic differences in NE may help to distinguish NE from mTLE.
Collapse
Affiliation(s)
- P Vermathen
- Department of Veterans Affairs Medical Center, San Francisco, CA 94121, USA
| | | | | | | | | | | |
Collapse
|
49
|
Cross JH, Gordon I, Connelly A, Jackson GD, Johnson CL, Neville BG, Gadian DG. Interictal 99Tc(m) HMPAO SPECT and 1H MRS in children with temporal lobe epilepsy. Epilepsia 1997; 38:338-45. [PMID: 9070597 DOI: 10.1111/j.1528-1157.1997.tb01126.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE To understand the pathological basis of focal hypoperfusion seen on interictal 99Tc(m) hexamethylpropyleneamine oxime (HMPAO) single-photon-emission computed tomography (SPECT) in intractable temporal lobe epilepsy, and to determine why the technique may be misleading in the localization and lateralization of the seizure focus in some cases. METHODS Interictal 99Tc(m) HMPAO SPECT and proton magnetic resonance spectroscopy (1H MRS) of the mesial temporal regions were performed in 14 children with intractable temporal lobe epilepsy not caused by a foreign tissue lesion. RESULTS Hypoperfusion of one temporal lobe ipsilateral to the seizure focus was demonstrated in 10 (71%) of the children; 1H MRS correctly lateralised in eight of these 10. No asymmetry of perfusion of the anterior temporal regions was seen in the remaining four children; on 1H MRS, three of these were bilaterally abnormal but nonlateralising. Repeated SPECT and 1H MRS in three children demonstrated changes over time, the findings from the two techniques being consistent with each other on both the initial and the repeated scans. CONCLUSIONS Abnormalities demonstrated by 1H MRS correlate well with those seen on interictal SPECT and can help to understand the pathologic basis of these SPECT abnormalities. Furthermore, the presence of bilateral damage can result in an absence of perfusion asymmetry on interictal SPECT.
Collapse
Affiliation(s)
- J H Cross
- Neurosciences Unit, Institute of Child Health, London, England
| | | | | | | | | | | | | |
Collapse
|
50
|
Ende GR, Laxer KD, Knowlton RC, Matson GB, Schuff N, Fein G, Weiner MW. Temporal lobe epilepsy: bilateral hippocampal metabolite changes revealed at proton MR spectroscopic imaging. Radiology 1997; 202:809-17. [PMID: 9051038 PMCID: PMC2733359 DOI: 10.1148/radiology.202.3.9051038] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE To determine which proton magnetic resonance (MR) spectroscopic imaging measures are best for lateralizing the seizure focus in patients who have temporal lobe epilepsy with and in those without hippocampal atrophy on MR images, the extent of contralateral abnormalities, and whether there is a correlation between MR spectroscopic imaging findings and surgical outcome. MATERIALS AND METHODS MR spectroscopic imaging was performed in 16 adult patients with temporal lobe epilepsy and unilateral electroencephalographic findings and in 16 adult control subjects. Eleven patients underwent surgery; all patients underwent MR imaging. RESULTS Nine patients had hippocampal atrophy on MR images. An ipsilateral decrease in the N-acetylaspartate concentration or the ratio of N-acetylaspartate to the sum of creatine and choline (N-acetylaspartate/ [creatine + choline]) was found in all patients. Decreased contralateral N-acetylaspartate concentration, N-acetylaspartate/(creatine + choline), or N-acetylaspartate concentration and N-acetylaspartate/(creatine + choline) were detected in eight patients (50%), which suggests bilateral abnormalities not detected with MR imaging. In the five patients who underwent surgery and did not show hippocampal atrophy on MR images, successful and unsuccessful outcomes were correctly predicted with N-acetylaspartate concentration. CONCLUSION Decreased N-acetylaspartate concentration is not due solely to hippocampal atrophy. Contralateral abnormalities are much more frequent than expected. MR spectroscopic imaging is valuable in the presurgical evaluation of epilepsy.
Collapse
Key Words
- brain, abnormalities, 1341.1214, 1341.12145, 13.83
- brain, atrophy, 1341.83
- brain, mr, 1341.1214, 1341.12145, 1341.83
- epilepsy, 1341.83
- magnetic resonance (mr), spectroscopy, 1341.12145
Collapse
Affiliation(s)
- G R Ende
- Central Institute of Mental Health, Mannheim, Germany
| | | | | | | | | | | | | |
Collapse
|