scholarly journals The Relationships Between Quantitative MR Parameters in Hippocampus in Healthy Subjects and Patients With Temporal Lobe Epilepsy

2015 ◽  
pp. 407-417 ◽  
Author(s):  
D. WAGNEROVÁ ◽  
V. HERYNEK ◽  
M. DEZORTOVÁ ◽  
P. MARUSIČ ◽  
P. KRŠEK ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Diffusion Tensor ◽  
Relaxation Times ◽  
Mean Diffusivity ◽  
Epileptogenic Zone ◽  
Quantitative Mr ◽  
Measurement Protocol ◽  
Mr Artifacts ◽  
Automated Processing

We introduce a new magnetic resonance (MR) method based on a pixel-by-pixel image processing to examine relationships between metabolic and structural processes in the pathologic hippocampus. The method was tested for lateralization of the epileptogenic zone in patients with temporal lobe epilepsy (TLE). Twenty patients with drug-resistant TLE and fifteen healthy controls were examined at 3T. The measurement protocol contained T2-weighted MR images, spectroscopic imaging, diffusion tensor imaging and T2 relaxometry. Correlations between quantitative MR parameters were calculated on a pixel-by-pixel basis using the CORIMA program which enables automated pixel identification in the normal tissue according to control data. All MR parameters changed in the anteroposterior direction in the hippocampus and correlation patterns and their slopes differed between patients and controls. Combinations of T2 relaxation times with metabolite values represent the best biomarkers of the epileptogenic zone. Correlations with mean diffusivity did not provide sufficiently accurate results due to diffusion image distortions. Quantitative MR analysis non-invasively provides a detailed description of hippocampal pathology and may represent complementary tool to the standard clinical protocol. However, the automated processing should be carefully monitored in order to avoid possible errors caused by MR artifacts.

scholarly journals Comparative Lateralizing Ability of Multimodality MRI in Temporal Lobe Epilepsy

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Karabekir Ercan ◽  
Hediye Pinar Gunbey ◽  
Erhan Bilir ◽  
Elcin Zan ◽  
Halil Arslan
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Diffusion Tensor ◽  
Febrile Convulsion ◽  
Significant Negative Correlation ◽  
Quantitative Mr ◽  
Single Voxel ◽  
Adc Values ◽  
History Of ◽  
Preoperative Examination

Purpose. The objective is to compare lateralizing ability of three quantitative MR (qMRI) modalities to depict changes of hippocampal architecture with clinical entities in temporal lobe epilepsy.Methods. We evaluated 14 patients with clinical and EEG proven diagnosis of unilateral TLE and 15 healthy volunteers. T1-weighted 3D dataset for volumetry, single-voxel1H MR spectroscopy (MRS), and diffusion tensor imaging (DTI) were performed for bilateral hippocampi of all subjects.Results. Individual volumetric measurements provided accurate lateralization in 85% of the patients, spectroscopy in 57%, and DTI in 57%. Higher lateralization ratios were acquired combining volumetry-spectroscopy (85%), spectroscopy-DTI (85%), and volumetry-DTI (100%). Significantly decreased NAA/(Cho+Cr) ratios (p=0.002) and increased FA (p=0.001) values were obtained in ipsilateral to epileptogenic hippocampus. Duration of epilepsy and FA values showed a significant negative correlation (p=0.016,r=-0.847). The history of febrile convulsion associated with ipsilateral increased ADC values (p=0.015,r=0.851) and reduced NAA/(Cho+Cr) ratios (p=0.047,r=-761).Conclusion. Volumetry, MRS, and DTI studies provide complementary information of hippocampal pathology. For lateralization of epileptogenic focus and preoperative examination, volumetry-DTI combination may be indicative of diagnostic accuracy.

scholarly journals Cognitive phenotypes in temporal lobe epilepsy are associated with distinct patterns of white matter network abnormalities

Neurology ◽  
2019 ◽  
Vol 92 (17) ◽  
pp. e1957-e1968 ◽  
Author(s):  
Anny Reyes ◽  
Erik Kaestner ◽  
Naeim Bahrami ◽  
Akshara Balachandra ◽  
Manu Hegde ◽  
...  
Keyword(s):  
White Matter ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Network Structure ◽  
Verbal Memory ◽  
Language Impairment ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Language Impaired ◽  
Impaired Group

ObjectiveTo identify distinct cognitive phenotypes in temporal lobe epilepsy (TLE) and evaluate patterns of white matter (WM) network alterations associated with each phenotype.MethodsSeventy patients with TLE were characterized into 4 distinct cognitive phenotypes based on patterns of impairment in language and verbal memory measures (language and memory impaired, memory impaired only, language impaired only, no impairment). Diffusion tensor imaging was obtained in all patients and in 46 healthy controls (HC). Fractional anisotropy (FA) and mean diffusivity (MD) of the WM directly beneath neocortex (i.e., superficial WM [SWM]) and of deep WM tracts associated with memory and language were calculated for each phenotype. Regional and network-based SWM analyses were performed across phenotypes.ResultsThe language and memory impaired group and the memory impaired group showed distinct patterns of microstructural abnormalities in SWM relative to HC. In addition, the language and memory impaired group showed widespread alterations in WM tracts and altered global SWM network topology. Patients with isolated language impairment exhibited poor network structure within perisylvian cortex, despite relatively intact global SWM network structure, whereas patients with no impairment appeared similar to HC across all measures.ConclusionsThese findings demonstrate a differential pattern of WM microstructural abnormalities across distinct cognitive phenotypes in TLE that can be appreciated at both the regional and network levels. These findings not only help to unravel the underlying neurobiology associated with cognitive impairment in TLE, but they could also aid in establishing cognitive taxonomies or in the prediction of cognitive course in TLE.

scholarly journals Synaptic Reshaping and Neuronal Outcomes in the Temporal Lobe Epilepsy

2021 ◽  
Vol 22 (8) ◽  
pp. 3860
Author(s):  
Elisa Ren ◽  
Giulia Curia
Keyword(s):  
Animal Models ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Current Knowledge ◽  
Focal Epilepsy ◽  
Ex Vivo ◽  
Hippocampal Sclerosis ◽  
Control Group ◽  
Epileptogenic Zone ◽  
Epileptiform Discharges

Temporal lobe epilepsy (TLE) is one of the most common types of focal epilepsy, characterized by recurrent spontaneous seizures originating in the temporal lobe(s), with mesial TLE (mTLE) as the worst form of TLE, often associated with hippocampal sclerosis. Abnormal epileptiform discharges are the result, among others, of altered cell-to-cell communication in both chemical and electrical transmissions. Current knowledge about the neurobiology of TLE in human patients emerges from pathological studies of biopsy specimens isolated from the epileptogenic zone or, in a few more recent investigations, from living subjects using positron emission tomography (PET). To overcome limitations related to the use of human tissue, animal models are of great help as they allow the selection of homogeneous samples still presenting a more various scenario of the epileptic syndrome, the presence of a comparable control group, and the availability of a greater amount of tissue for in vitro/ex vivo investigations. This review provides an overview of the structural and functional alterations of synaptic connections in the brain of TLE/mTLE patients and animal models.

scholarly journals Multi-scale image analysis and prediction of visual field defects after selective amygdalohippocampectomy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bastian David ◽  
Jasmine Eberle ◽  
Daniel Delev ◽  
Jennifer Gaubatz ◽  
Conrad C. Prillwitz ◽  
...  
Keyword(s):  
Visual Field ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Diffusion Tensor ◽  
Global Network ◽  
Visual Field Defects ◽  
Whole Brain ◽  
Network Analyses ◽  
Postoperative Mri ◽  
Selective Amygdalohippocampectomy

AbstractSelective amygdalohippocampectomy is an effective treatment for patients with therapy-refractory temporal lobe epilepsy but may cause visual field defect (VFD). Here, we aimed to describe tissue-specific pre- and postoperative imaging correlates of the VFD severity using whole-brain analyses from voxel- to network-level. Twenty-eight patients with temporal lobe epilepsy underwent pre- and postoperative MRI (T1-MPRAGE and Diffusion Tensor Imaging) as well as kinetic perimetry according to Goldmann standard. We probed for whole-brain gray matter (GM) and white matter (WM) correlates of VFD using voxel-based morphometry and tract-based spatial statistics, respectively. We furthermore reconstructed individual structural connectomes and conducted local and global network analyses. Two clusters in the bihemispheric middle temporal gyri indicated a postsurgical GM volume decrease with increasing VFD severity (FWE-corrected p < 0.05). A single WM cluster showed a fractional anisotropy decrease with increasing severity of VFD in the ipsilesional optic radiation (FWE-corrected p < 0.05). Furthermore, patients with (vs. without) VFD showed a higher number of postoperative local connectivity changes. Neither in the GM, WM, nor in network metrics we found preoperative correlates of VFD severity. Still, in an explorative analysis, an artificial neural network meta-classifier could predict the occurrence of VFD based on presurgical connectomes above chance level.

scholarly journals Localization of epileptogenic zone in temporal lobe epilepsy by ictal scalp EEG

Seizure ◽  
2002 ◽  
Vol 11 (3) ◽  
pp. 163-168 ◽  
Author(s):  
Yuzo Sakai ◽  
Hiromi Nagano ◽  
Ayumi Sakata ◽  
Sachiko Kinoshita ◽  
Naotaka Hamasaki ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Epileptogenic Zone ◽  
Scalp Eeg

scholarly journals Role of Diffusion Tensor Imaging in Detection and Lateralization of Temporal Lobe Epilepsy

2018 ◽  
Vol 86 (9) ◽  
pp. 2501-2505
Author(s):  
NERMEEN M.S. GARHY, M.D.; AMR O.M.A. AZAB, M.D. ◽  
RANIA Z. HASSAN, M.D.; ASMAA M. EBRAHEIM, M.D.
Keyword(s):  
Diffusion Tensor Imaging ◽  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Diffusion Tensor

scholarly journals Recent developments in cognitive fMRI for temporal lobe epilepsy

2019 ◽  
Vol 33 (1) ◽  
pp. 30-36 ◽  
Author(s):  
Victor Schmidbauer ◽  
Silvia Bonelli
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Visual Memory ◽  
Imaging Modality ◽  
Memory Function ◽  
Brain Regions ◽  
Epileptogenic Zone ◽  
Brain Areas ◽  
Recent Developments ◽  
The Brain

AbstractEpilepsy is frequently accompanied by severe cognitive side effects. Temporal lobe epilepsy (TLE), and even successful surgical treatment, may affect cognitive function, in particular language as well as verbal and visual memory function. Epilepsy arising from the temporal lobe can be controlled surgically in up to 70% of patients. The goals of epilepsy surgery are to remove the brain areas generating the seizures without causing or aggravating neuropsychological deficits. This requires accurate localization of the brain areas generating the seizures (“epileptogenic zone”) and the areas responsible for motor and cognitive functions, such as language and memory (“essential brain regions”) during presurgical evaluation. In the past decades, functional magnetic resonance imaging (fMRI) has been increasingly used to noninvasively lateralize and localize not only primary motor and somatosensory areas, but also brain areas that are involved in everyday language and memory processes. The imaging modality also shows potential for predicting the effects of temporal lobe resection on language and memory function. Together with other MRI modalities, cognitive fMRI is a promising tool to improve surgical strategies tailored to individual patients with regard to functional outcome, by virtue of definition of epileptic cerebral areas that need to be resected and eloquent areas that need to be spared.The aim of this review is to provide an overview of recent developments and practical recommendations for the clinical use of cognitive fMRI in TLE.

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