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Metodiev D, Minkin K, Ruseva M, Ganeva R, Parvanov D, Nachev S. Pathomorphological Diagnostic Criteria for Focal Cortical Dysplasias and Other Common Epileptogenic Lesions—Review of the Literature. Diagnostics (Basel) 2023; 13:diagnostics13071311. [PMID: 37046529 PMCID: PMC10092959 DOI: 10.3390/diagnostics13071311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/20/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023] Open
Abstract
Focal cortical dysplasia (FCD) represents a heterogeneous group of morphological changes in the brain tissue that can predispose the development of pharmacoresistant epilepsy (recurring, unprovoked seizures which cannot be managed with medications). This group of neurological disorders affects not only the cerebral cortex but also the subjacent white matter. This work reviews the literature describing the morphological substrate of pharmacoresistant epilepsy. All illustrations presented in this study are obtained from brain biopsies from refractory epilepsy patients investigated by the authors. Regarding classification, there are three main FCD types, all of which involve cortical dyslamination. The 2022 revision of the International League Against Epilepsy (ILAE) FCD classification includes new histologically defined pathological entities: mild malformation of cortical development (mMCD), mild malformation of cortical development with oligodendroglial hyperplasia in frontal lobe epilepsy (MOGHE), and “no FCD on histopathology”. Although the pathomorphological characteristics of the various forms of focal cortical dysplasias are well known, their aetiologic and pathogenetic features remain elusive. The identification of genetic variants in FCD opens an avenue for novel treatment strategies, which are of particular utility in cases where total resection of the epileptogenic area is impossible.
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Helmstaedter C, Winter B, Melzer N, Lohmann H, Witt JA. Accelerated long-term forgetting in focal epilepsies with special consideration given to patients with diagnosed and suspected limbic encephalitis. Cortex 2019; 110:58-68. [DOI: 10.1016/j.cortex.2018.01.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Revised: 07/13/2017] [Accepted: 01/05/2018] [Indexed: 02/04/2023]
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Jain RS, Khan I, Nagpal K. Identification of structural lesion using a 3-Tesla MRI in partial onset epilepsy with a normal CT scan: A perspective of a tertiary centre in Northern India. INDIAN JOURNAL OF MEDICAL SPECIALITIES 2018. [DOI: 10.1016/j.injms.2018.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kogias E, Klingler JH, Urbach H, Scheiwe C, Schmeiser B, Doostkam S, Zentner J, Altenmüller DM. 3 Tesla MRI-negative focal epilepsies: Presurgical evaluation, postoperative outcome and predictive factors. Clin Neurol Neurosurg 2017; 163:116-120. [PMID: 29101859 DOI: 10.1016/j.clineuro.2017.10.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 10/26/2017] [Accepted: 10/29/2017] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To investigate presurgical diagnostic modalities, clinical and seizure outcome as well as predictive factors after resective epilepsy surgery in 3 Tesla MRI-negative focal epilepsies. PATIENTS AND METHODS This retrospective study comprises 26 patients (11 males/15 females, mean age 34±12years, range 13-50 years) with 3 Tesla MRI-negative focal epilepsies who underwent resective epilepsy surgery. Non-invasive and invasive presurgical diagnostic modalities, type and localization of resection, clinical and epileptological outcome with a minimum follow-up of 1year (range 1-11 years, mean 2.5±2.3years) after surgery as well as outcome predictors were evaluated. RESULTS All patients underwent invasive video-EEG monitoring after implantation of intracerebral depth and/or subdural electrodes. Ten patients received temporal and 16 extratemporal or multilobar (n=4) resections. There was no perioperative death or permanent morbidity. Overall, 12 of 26 patients (46%) were completely seizure-free (Engel IA) and 65% had a favorable outcome (Engel I-II). In particular, seizure-free ratio was 40% in the temporal and 50% in the extratemporal group. In the temporal group, long duration of epilepsy correlated with poor seizure outcome, whereas congruent unilateral FDG-PET hypometabolism correlated with a favorable outcome. CONCLUSIONS In almost two thirds of temporal and extratemporal epilepsies defined as "non-lesional" by 3 Tesla MRI criteria, a favorable postoperative seizure outcome (Engel I-II) can be achieved with accurate multimodal presurgical evaluation including intracranial EEG recordings. In the temporal group, most favorable results were obtained when FDG-PET displayed congruent unilateral hypometabolism.
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Affiliation(s)
- Evangelos Kogias
- Department of Neurosurgery, Medical Center-University of Freiburg, Germany.
| | - Jan-Helge Klingler
- Department of Neurosurgery, Medical Center-University of Freiburg, Germany
| | - Horst Urbach
- Department of Neuroradiology, Medical Center-University of Freiburg, Germany
| | - Christian Scheiwe
- Department of Neurosurgery, Medical Center-University of Freiburg, Germany
| | - Barbara Schmeiser
- Department of Neurosurgery, Medical Center-University of Freiburg, Germany
| | - Soroush Doostkam
- Institute of Neuropathology, Medical Center-University of Freiburg, Germany
| | - Josef Zentner
- Department of Neurosurgery, Medical Center-University of Freiburg, Germany
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Malter MP, Widman G, Galldiks N, Stoecker W, Helmstaedter C, Elger CE, Wagner J. Suspected new-onset autoimmune temporal lobe epilepsy with amygdala enlargement. Epilepsia 2016; 57:1485-94. [PMID: 27418040 DOI: 10.1111/epi.13471] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2016] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Recent reports define temporal lobe epilepsy with amygdala enlargement (TLE-AE) as a distinct electroclinical syndrome comparable to TLE with hippocampal sclerosis. In this retrospective observational study, we present the largest consecutive series of patients with new-onset TLE-AE to date and describe clinical characteristics and seizure outcome, and we aim to explore underlying autoimmune mechanisms within this syndrome. METHODS We reviewed all consecutive patients between 2004 and 2014 at our tertiary epilepsy center at the University of Bonn, Germany, with new-onset (<5 years) TLE-AE, negative serum antibody (ab) test results, and with available follow-up data for at least 12 months. RESULTS We identified 40 patients (23 male) with TLE-AE with a median age at epilepsy onset of 51 years (range 10-73) and a median disease duration of 11 months (range 0.5-55) at first presentation. At follow-up, 50% of the entire cohort achieved seizure freedom. Of interest, patients with remittent features of AE at follow-up (N = 24) had a superior outcome compared to those with stable magnetic resonance imaging (MRI) features of AE (N = 16): 17 (71%) of 24 were seizure-free for at least 6 months compared to 3 (19%) of 16, respectively (p = 0.003). MRI volumetry confirmed significantly enlarged amygdalae in TLE-AE in relation to healthy controls, and additionally showed significantly greater volume reductions in patients with remittent AE compared to those with stable AE. SIGNIFICANCE TLE-AE is a clinical syndrome beginning mostly in middle age, and in addition to its known association with ab-positive limbic encephalitis, it occurs in an ab-negative condition. Remission of AE in the course of the disease could be identified as a predictor for a favorable clinical outcome and is suspicious of an autoimmune etiology, although we could not confirm this hypothesis unequivocally with currently available noninvasive diagnostic tools.
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Affiliation(s)
- Michael P Malter
- Department of Epileptology, University of Bonn, Bonn, Germany.,Department of Neurology, University of Cologne, Cologne, Germany
| | - Guido Widman
- Department of Epileptology, University of Bonn, Bonn, Germany
| | - Norbert Galldiks
- Department of Neurology, University of Cologne, Cologne, Germany.,Institute of Neuroscience and Medicine, Research Center Juelich, Juelich, Germany
| | - Winfried Stoecker
- Institute of Experimental Immunology, Affiliated to Euroimmun AG, Luebeck, Germany
| | | | - Christian E Elger
- Department of Epileptology, University of Bonn, Bonn, Germany.,Department of NeuroCognition/Imaging, Life & Brain Centre, Bonn, Germany
| | - Jan Wagner
- Department of Epileptology, University of Bonn, Bonn, Germany.,Department of NeuroCognition/Imaging, Life & Brain Centre, Bonn, Germany.,Department of Neurology, Epilepsy Center Hessen-Marburg, University of Marburg Medical Centre, Marburg, Germany
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Wagner J, Schoene-Bake JC, Witt JA, Helmstaedter C, Malter MP, Stoecker W, Probst C, Weber B, Elger CE. Distinct white matter integrity in glutamic acid decarboxylase and voltage-gated potassium channel-complex antibody-associated limbic encephalitis. Epilepsia 2016; 57:475-83. [PMID: 26749370 DOI: 10.1111/epi.13297] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2015] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Autoantibodies against glutamic acid decarboxylase (GAD) and the voltage-gated potassium channel (VGKC) complex are associated with distinct subtypes of limbic encephalitis regarding clinical presentation, response to therapy, and outcome. The aim of this study was to investigate white matter changes in these two limbic encephalitis subtypes by means of diffusion tensor imaging (DTI). METHODS Diffusion data were obtained in 14 patients with GAD antibodies and 16 patients with VGKC-complex antibodies and compared with age- and gender-matched control groups. Voxelwise statistical analysis was carried out using tract-based spatial statistics. The results were furthermore compared with those of 15 patients with unilateral histologically confirmed hippocampal sclerosis and correlated with verbal and figural memory performance. RESULTS We found widespread changes of fractional anisotropy and all diffusivity parameters in GAD-associated limbic encephalitis, whereas no changes were found in VGKC-complex-associated limbic encephalitis. The changes observed in the GAD group were even more extensive when compared against those of the hippocampal sclerosis group, although the disease duration was markedly shorter in patients with GAD antibodies. Correlation analysis revealed areas with a trend toward a negative correlation of diffusivity parameters with figural memory performance located mainly in the right temporal lobe in the GAD group as well. SIGNIFICANCE The present study provides further evidence that, depending on the associated antibody, limbic encephalitis features clearly distinct imaging characteristics by showing widespread white matter changes in GAD-associated limbic encephalitis and preserved white matter integrity in VGKC-complex-associated limbic encephalitis. Furthermore, our results contribute to a better understanding of the specific pathophysiologic properties in these two subforms of limbic encephalitis by revealing that patients with GAD antibodies show widespread affections of white matter across various regions of the brain. In contrast to this, the inflammatory process seems to be more localized in VGKC-complex-associated limbic encephalitis, primarily affecting mesiotemporal gray matter.
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Affiliation(s)
- Jan Wagner
- Department of Epileptology, University of Bonn, Bonn, Germany.,Department of NeuroCognition/Imaging, Life & Brain Center, Bonn, Germany
| | - Jan-Christoph Schoene-Bake
- Department of Epileptology, University of Bonn, Bonn, Germany.,Department of NeuroCognition/Imaging, Life & Brain Center, Bonn, Germany.,Department of Pediatrics, Klinikum Braunschweig, Braunschweig, Germany
| | | | | | - Michael P Malter
- Department of Epileptology, University of Bonn, Bonn, Germany.,Department of Neurology, University of Cologne, Cologne, Germany
| | - Winfried Stoecker
- Institute of Experimental Immunology, affiliated with Euroimmun AG Luebeck, Luebeck, Germany
| | - Christian Probst
- Institute of Experimental Immunology, affiliated with Euroimmun AG Luebeck, Luebeck, Germany
| | - Bernd Weber
- Department of Epileptology, University of Bonn, Bonn, Germany.,Department of NeuroCognition/Imaging, Life & Brain Center, Bonn, Germany.,Center for Economics and Neuroscience, University of Bonn, Bonn, Germany
| | - Christian E Elger
- Department of Epileptology, University of Bonn, Bonn, Germany.,Department of NeuroCognition/Imaging, Life & Brain Center, Bonn, Germany.,Center for Economics and Neuroscience, University of Bonn, Bonn, Germany
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Proton magnetic resonance spectroscopy in focal cortical dysplasia at 3T. Seizure 2015; 32:23-9. [PMID: 26552557 DOI: 10.1016/j.seizure.2015.08.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 08/12/2015] [Accepted: 08/22/2015] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Focal cortical dysplasia (FCD) type II is a frequent cause of medically intractable epilepsy. On conventional MRI diagnosis may be difficult. The purpose of our study was to assess the metabolic characteristics of MRI-typical or neuropathologically confirmed FCD II lesions at 3T. METHODS In a prospective study, 13 patients with drug-resistant epilepsy and MRI diagnosis of FCD II (seven neuropathologically confirmed) were investigated by single-volume proton magnetic resonance spectroscopy ((1)H MRS). We performed an intra-individual comparison placing spectroscopic volumes of interest in the lesion and in the apparently normal contralateral hemisphere. Spectroscopic results were correlated with clinical data. RESULTS Matched pair analysis revealed a significant increase in absolute choline (Cho) concentration in the lesion volume (+32%, p=0.015) compared to the control volume. This increase was associated with a significant decrease in N-acetyl-aspartate (NAA) concentration (-13%; p=0.008). Mean myo-inositol (Ins) levels were distinctly (+36%) but not significantly (p=0.051) elevated. Lesional creatine (Cr) concentration correlated significantly with the frequency of seizures (Spearman-Rho r=0.898; p=0.002), while concentrations of NAA, Cho and Ins did not correlate with clinical or imaging parameters. CONCLUSION MR spectroscopy revealed a characteristic metabolic pattern in FCD II lesions that helps to distinguish normal from epileptogenic tissue.
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Ramli N, Rahmat K, Lim KS, Tan CT. Neuroimaging in refractory epilepsy. Current practice and evolving trends. Eur J Radiol 2015; 84:1791-800. [PMID: 26187861 DOI: 10.1016/j.ejrad.2015.03.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 03/09/2015] [Accepted: 03/21/2015] [Indexed: 11/16/2022]
Abstract
Identification of the epileptogenic zone is of paramount importance in refractory epilepsy as the success of surgical treatment depends on complete resection of the epileptogenic zone. Imaging plays an important role in the locating and defining anatomic epileptogenic abnormalities in patients with medically refractory epilepsy. The aim of this article is to present an overview of the current MRI sequences used in epilepsy imaging with special emphasis of lesion seen in our practices. Optimisation of epilepsy imaging protocols are addressed and current trends in functional MRI sequences including MR spectroscopy, diffusion tensor imaging and fusion MR with PET and SPECT are discussed.
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Affiliation(s)
- N Ramli
- Department of Biomedical Imaging, University Malaya Research Imaging Centre, Malaysia
| | - K Rahmat
- Department of Biomedical Imaging, University Malaya Research Imaging Centre, Malaysia.
| | - K S Lim
- Neurology Unit, Department of Medicine, University Malaya, Kuala Lumpur, Malaysia
| | - C T Tan
- Neurology Unit, Department of Medicine, University Malaya, Kuala Lumpur, Malaysia
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Wagner J, Weber B, Elger CE. Early and chronic gray matter volume changes in limbic encephalitis revealed by voxel-based morphometry. Epilepsia 2015; 56:754-61. [DOI: 10.1111/epi.12968] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2015] [Indexed: 12/26/2022]
Affiliation(s)
- Jan Wagner
- Department of Epileptology; University of Bonn; Bonn Germany
- Department of NeuroCognition/Imaging; Life & Brain Center; Bonn Germany
| | - Bernd Weber
- Department of Epileptology; University of Bonn; Bonn Germany
- Department of NeuroCognition/Imaging; Life & Brain Center; Bonn Germany
- Center for Economics and Neuroscience; University of Bonn; Bonn Germany
| | - Christian E. Elger
- Department of Epileptology; University of Bonn; Bonn Germany
- Department of NeuroCognition/Imaging; Life & Brain Center; Bonn Germany
- Center for Economics and Neuroscience; University of Bonn; Bonn Germany
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Urbach H, Huppertz HJ, Schwarzwald R, Becker AJ, Wagner J, Bahri MD, Tschampa HJ. Is the type and extent of hippocampal sclerosis measurable on high-resolution MRI? Neuroradiology 2014; 56:731-5. [PMID: 24973130 DOI: 10.1007/s00234-014-1397-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 06/18/2014] [Indexed: 11/26/2022]
Abstract
INTRODUCTION The purpose of this study is to relate hippocampal volume and FLAIR signal intensity to Wyler grading of hippocampal sclerosis (HS). METHODS Of 100 consecutive patients with temporal lobe epilepsy and HS as histopathological diagnosis, 32 had high-resolution 3 Tesla MRI and anatomically well-preserved hippocampi following amygdalo-hippocampectomy. Hippocampal volume on 3D T1-weighted gradient echo and signal intensity on coronal FLAIR sequences were determined using FreeSurfer and SPM tools and related to Wyler grading. Seizure outcome was determined after 1 year. RESULTS Histopathology showed four Wyler II, 19 Wyler III, and 9 Wyler IV HS. Hippocampal volumes were 3.08 ml for Wyler II (Wyler II/contralateral side: p > 0.05), 2.19 ml for Wyler III (p < 0.01), 2.62 ml for Wyler IV (p = 0.01), and 3.08 ml for the contralateral side. Normalized FLAIR signals were 1,354 (p = 0.0004), 1,408 (p < 0.0001), 1,371 (p < 0.04), and 1,296, respectively. Wyler II hippocampi were visually normal. Two of four (50%) Wyler II, 16/19 (84%) Wyler III, and 6/9 (66%) Wyler IV patients achieved Engel I outcome. CONCLUSIONS Combined volumetry and quantitative FLAIR signal analysis clearly identifies Wyler III and IV HS. Quantitative FLAIR signal analysis may be helpful to identify Wyler II HS.
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Affiliation(s)
- H Urbach
- Dept. of Neuroradiology, Medical Center University of Freiburg, Breisacher Str. 64, 79106, Freiburg, Germany,
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von der Brelie C, Kuczaty S, von Lehe M. Surgical management and long-term outcome of pediatric patients with different subtypes of epilepsy associated with cerebral cavernous malformations. J Neurosurg Pediatr 2014; 13:699-705. [PMID: 24702617 DOI: 10.3171/2014.2.peds13361] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Sufficient data on surgical treatment and seizure outcome of pediatric patients with different types of epilepsy, especially drug-resistant epilepsy and associated cerebral cavernous malformations, are scarce. The aim of this study was to carefully evaluate seizure outcome using the International League Against Epilepsy (ILAE) classification with regard to the presurgical symptom duration. METHODS Fifty-one pediatric patients younger than 19 years with cerebral cavernous malformations of all CNS localizations have been surgically treated at the authors' institution. Twenty-two patients with seizures or epilepsy who harbored cortically located supratentorial cerebral cavernous malformations underwent surgical treatment and were retrospectively analyzed. RESULTS More extensive resections were used in 82% of all patients with epilepsy symptoms for longer than 2 years. Eighty-two percent of patients with symptom duration shorter than 2 years underwent circumscribed lesionectomy including the surrounding hemosiderotic rim. The overall rate of mild permanent, unanticipated postoperative deficits was 4.5%; the rate of anticipated neurological deficits was 9%. The mean follow-up was longer than 117 months in all groups. Seizure outcome was excellent in the group with symptom duration shorter than 2 years (100% ILAE Class 1). Seizure outcome was significantly worse in the group with longer symptom duration (p = 0.02). Seven patients were seizure free after surgery. Seizure outcome was stable over the years. CONCLUSIONS Since seizure outcome is worse with longer seizure duration, early surgery and, if needed, interdisciplinary intervention, is recommended. Even in cases of multiple cerebral cavernous malformations and epilepsy, surgery should be considered.
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Wellmer J, Quesada CM, Rothe L, Elger CE, Bien CG, Urbach H. Proposal for a magnetic resonance imaging protocol for the detection of epileptogenic lesions at early outpatient stages. Epilepsia 2013; 54:1977-87. [DOI: 10.1111/epi.12375] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2013] [Indexed: 01/04/2023]
Affiliation(s)
- Jörg Wellmer
- Ruhr-Epileptology; Department of Neurology; University Hospital Knappschaftskrankenhaus; Bochum Germany
| | - Carlos M. Quesada
- Department of Epileptology & Life and Brain Institute; University Hospital Bonn; Bonn Germany
| | - Lars Rothe
- Ruhr-Epileptology; Department of Neurology; University Hospital Knappschaftskrankenhaus; Bochum Germany
| | - Christian E. Elger
- Department of Epileptology & Life and Brain Institute; University Hospital Bonn; Bonn Germany
| | | | - Horst Urbach
- Department of Neuroradiology; University Hospital Freiburg; Freiburg Germany
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Wagner J, Schoene-Bake JC, Malter MP, Urbach H, Huppertz HJ, Elger CE, Weber B. Quantitative FLAIR analysis indicates predominant affection of the amygdala in antibody-associated limbic encephalitis. Epilepsia 2013; 54:1679-87. [PMID: 23889589 DOI: 10.1111/epi.12320] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2013] [Indexed: 02/06/2023]
Abstract
PURPOSE Limbic encephalitis is an autoimmune-mediated disease leading to temporal lobe epilepsy, mnestic deficits, and affective disturbances. Magnetic resonance imaging (MRI) usually shows signal and volume changes of the temporomesial structures. However, these abnormalities may be subtle, thereby hampering the diagnosis by conventional visual assessment. In the present study we evaluated the diagnostic value of a fully automated MRI postprocessing technique in limbic encephalitis and hippocampal sclerosis. METHODS The MRI postprocessing was based largely on a recently described method allowing for an observer-independent quantification of the fluid-attenuated inversion recovery (FLAIR) signal intensities of amygdala and hippocampus. A 95% confidence region was calculated from the FLAIR intensities of 100 healthy controls. We applied this analysis to the MRI data of 39 patients with antibody-associated limbic encephalitis and 63 patients with hippocampal sclerosis. Moreover, the results were compared to those of visual assessment by an experienced neuroradiologist. KEY FINDINGS The method detected limbic encephalitis and hippocampal sclerosis with a high sensitivity of 85% and 95%, respectively. The detection rate of the automated approach in limbic encephalitis was significantly superior to visual analysis (85% vs. 51%; p = 0.001), whereas no statistically significant difference for the detection rate in hippocampal sclerosis was found. Patients with limbic encephalitis had significantly higher absolute intensity values of the amygdala and a significantly higher percentage fell outside of the amygdalar confidence region compared to those with hippocampal sclerosis (79% vs. 27%; p < 0.001), whereas we found opposite results in the hippocampal analysis (38% vs. 95%; p < 0.001). SIGNIFICANCE The FLAIR analysis applied in this study is a powerful tool to quantify signal changes of the amygdala and hippocampus in limbic encephalitis and hippocampal sclerosis. It significantly increases the diagnostic sensitivity in limbic encephalitis in comparison to conventional visual analysis. Furthermore, the method provides an interesting insight into the distinct properties of these two disease entities on MRI, indicating a predominant affection of the amygdala in limbic encephalitis, whereas the affection of the hippocampus is far less pronounced when compared to hippocampal sclerosis.
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Affiliation(s)
- Jan Wagner
- Department of Epileptology, University of Bonn, Bonn, Germany.
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Obenaus A. Neuroimaging biomarkers for epilepsy: advances and relevance to glial cells. Neurochem Int 2013; 63:712-8. [PMID: 23665337 DOI: 10.1016/j.neuint.2013.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 04/24/2013] [Accepted: 05/01/2013] [Indexed: 12/11/2022]
Abstract
Glial cells play an important role in normal brain function and emerging evidence would suggest that their dysfunction may be responsible for some epileptic disease states. Neuroimaging of glial cells is desirable, but there are no clear methods to assess neither their function nor localization. Magnetic resonance imaging (MRI) is now part of a standardized epilepsy imaging protocol to assess patients. Structural volumetric and T2-weighted imaging changes can assist in making a positive diagnosis in a majority of patients. The alterations reported in structural and T2 imaging is predominantly thought to reflect early neuronal loss followed by glial hypertrophy. MR spectroscopy for myo-inositol is a being pursued to identify glial alterations along with neuronal markers. Diffusion weighted imaging (DWI) is ideal for acute epileptiform events, but is not sensitive to either glial cells or neuronal long-term changes found in epilepsy. However, DWI variants such as diffusion tensor imaging or q-space imaging may shed additional light on aberrant glial function in the future. The sensitivity and specificity of PET radioligands, including those targeting glial cells (translocator protein) hold promise in being able to image glial cells. As the role of glial function/dysfunction in epilepsy becomes more apparent neuroimaging methods will evolve to assist the clinician and researcher in visualizing their location and function.
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Affiliation(s)
- Andre Obenaus
- Department of Pediatrics, School of Medicine, Loma Linda University, Loma Linda, CA, USA; Division of Interdisciplinary Studies, School of Behavioral Health, Loma Linda University, Loma Linda, CA, USA; Cell and Molecular Development and Biology Program, University of California, Riverside, CA, USA; Neuroscience Graduate Program, University of California, Riverside, CA, USA.
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