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Saute RL, Peixoto-Santos JE, Velasco TR, Leite JP. Improving surgical outcome with electric source imaging and high field magnetic resonance imaging. Seizure 2021; 90:145-154. [PMID: 33608134 DOI: 10.1016/j.seizure.2021.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/26/2021] [Accepted: 02/04/2021] [Indexed: 12/14/2022] Open
Abstract
While most patients with focal epilepsy present with clear structural abnormalities on standard, 1.5 or 3 T MRI, some patients are MRI-negative. For those, quantitative MRI techniques, such as volumetry, voxel-based morphometry, and relaxation time measurements can aid in finding the epileptogenic focus. High-field MRI, just recently approved for clinical use by the FDA, increases the resolution and, in several publications, was shown to improve the detection of focal cortical dysplasias and mild cortical malformations. For those cases without any tissue abnormality in neuroimaging, even at 7 T, scalp EEG alone is insufficient to delimitate the epileptogenic zone. They may benefit from the use of high-density EEG, in which the increased number of electrodes helps improve spatial sampling. The spatial resolution of even low-density EEG can benefit from electric source imaging techniques, which map the source of the recorded abnormal activity, such as interictal epileptiform discharges, focal slowing, and ictal rhythm. These EEG techniques help localize the irritative, functional deficit, and seizure-onset zone, to better estimate the epileptogenic zone. Combining those technologies allows several drug-resistant cases to be submitted to surgery, increasing the odds of seizure freedom and providing a must needed hope for patients with epilepsy.
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Affiliation(s)
- Ricardo Lutzky Saute
- Department of Neurosciences and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Brazil
| | - Jose Eduardo Peixoto-Santos
- Discipline of Neuroscience, Department of Neurology and Neurosurgery, Paulista School of Medicine, Unifesp, Brazil
| | - Tonicarlo R Velasco
- Department of Neurosciences and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Brazil
| | - Joao Pereira Leite
- Department of Neurosciences and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Brazil.
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Guo Y, Liu Y, Ming W, Wang Z, Zhu J, Chen Y, Yao L, Ding M, Shen C. Distinguishing Focal Cortical Dysplasia From Glioneuronal Tumors in Patients With Epilepsy by Machine Learning. Front Neurol 2020; 11:548305. [PMID: 33329300 PMCID: PMC7732488 DOI: 10.3389/fneur.2020.548305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 10/14/2020] [Indexed: 11/13/2022] Open
Abstract
Purpose: We are aiming to build a supervised machine learning-based classifier, in order to preoperatively distinguish focal cortical dysplasia (FCD) from glioneuronal tumors (GNTs) in patients with epilepsy. Methods: This retrospective study was comprised of 96 patients who underwent epilepsy surgery, with the final neuropathologic diagnosis of either an FCD or GNTs. Seven classical machine learning algorithms (i.e., Random Forest, SVM, Decision Tree, Logistic Regression, XGBoost, LightGBM, and CatBoost) were employed and trained by our dataset to get the classification model. Ten features [i.e., Gender, Past history, Age at seizure onset, Course of disease, Seizure type, Seizure frequency, Scalp EEG biomarkers, MRI features, Lesion location, Number of antiepileptic drug (AEDs)] were analyzed in our study. Results: We enrolled 56 patients with FCD and 40 patients with GNTs, which included 29 with gangliogliomas (GGs) and 11 with dysembryoplasic neuroepithelial tumors (DNTs). Our study demonstrated that the Random Forest-based machine learning model offered the best predictive performance on distinguishing the diagnosis of FCD from GNTs, with an F1-score of 0.9180 and AUC value of 0.9340. Furthermore, the most discriminative factor between FCD and GNTs was the feature "age at seizure onset" with the Chi-square value of 1,213.0, suggesting that patients who had a younger age at seizure onset were more likely to be diagnosed as FCD. Conclusion: The Random Forest-based machine learning classifier can accurately differentiate FCD from GNTs in patients with epilepsy before surgery. This might lead to improved clinician confidence in appropriate surgical planning and treatment outcomes.
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Affiliation(s)
- Yi Guo
- Department of General Practice, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China.,Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Yushan Liu
- School of Computer Science, Fudan University, Shanghai, China
| | - Wenjie Ming
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China.,Department of Neurology, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Zhongjin Wang
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China.,Department of Neurology, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Junming Zhu
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China.,Department of Neurosurgery, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Yang Chen
- School of Computer Science, Fudan University, Shanghai, China
| | - Lijun Yao
- Shanghai Pudong New Area Mental Health Center, Tongji University School of Medicine, Shanghai, China
| | - Meiping Ding
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China.,Department of Neurology, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Chunhong Shen
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China.,Department of Neurology, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
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Warsi NM, Lasry O, Farah A, Saint-Martin C, Montes JL, Atkinson J, Farmer JP, Dudley RWR. 3-T intraoperative MRI (iMRI) for pediatric epilepsy surgery. Childs Nerv Syst 2016; 32:2415-2422. [PMID: 27757571 DOI: 10.1007/s00381-016-3263-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 10/03/2016] [Indexed: 10/20/2022]
Abstract
PURPOSE Three-tesla intraoperative MRI (iMRI) is a promising tool that could help confirm complete resections and disconnections in pediatric epilepsy surgery, leading to improved outcomes. However, a large proportion of epileptogenic pathologies in children are poorly defined on imaging, which brings into question the utility of iMRI for these cases. Our aim was to compare postoperative seizure outcomes between iMRI- and non-iMRI-based epilepsy surgeries. METHODS We performed a comparative retrospective analysis of non-iMRI- versus iMRI-based epilepsy surgeries with 2-year follow-up. Patients were stratified into well-defined cases (WDCs), poorly defined cases (PDCs), and diffuse hemispheric cases (DHCs). Primary outcomes were rates of complete seizure freedom and surgical complications. Secondary outcomes included good (Engel class I/II) seizure outcome, extent of resection/disconnection, and operative duration. Regression models were used to adjust for confounding. RESULTS Thirty-nine iMRI-based and 39 non-iMRI-based surgeries were included. The distributions of age, sex, and lesion class in each era were similar, but the distributions of individual pathologies varied. Seizure freedom and complication rates at 2-year follow-up were not different between the groups, but Engel class I/II outcome was more common in the iMRI group. Extent of resection/disconnection and length of surgery were similar in both groups. PDCs had the worst outcomes, which were unchanged by the use of iMRI. CONCLUSION Three-tesla iMRI-based epilepsy surgery may have the potential to improve patient outcomes. However, we conclude that iMRI, in its current state of use at our institute, does not improve outcomes for children undergoing epilepsy surgery. Given that its use appears safe, further research on this technology is warranted, particularly for the most challenging PDCs.
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Affiliation(s)
- Nebras M Warsi
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
| | - Oliver Lasry
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada. .,Department of Epidemiology, Biostatistics and Occupational Health, Faculty of Medicine, McGill University, 1020 Pine Avenue West, Montréal, QC, H3A 1A2, Canada.
| | - Adel Farah
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
| | - Christine Saint-Martin
- Department of Medical Imaging, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
| | - Jose L Montes
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
| | - Jeffrey Atkinson
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
| | - Jean-Pierre Farmer
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
| | - Roy W R Dudley
- Division of Neurosurgery, Department of Pediatric Surgery, Montreal Children's Hospital, McGill University Health Centre, Montreal, QC, Canada
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Leach JL, Greiner HM, Miles L, Mangano FT. Imaging Spectrum of Cortical Dysplasia in Children. Semin Roentgenol 2014; 49:99-111. [DOI: 10.1053/j.ro.2013.10.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Naraghi A, da Gama Lobo L, Menezes R, Khanna M, Sussman M, Anastakis D, White LM. Diffusion tensor imaging of the median nerve before and after carpal tunnel release in patients with carpal tunnel syndrome: feasibility study. Skeletal Radiol 2013; 42:1403-12. [PMID: 23842572 DOI: 10.1007/s00256-013-1670-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 05/20/2013] [Accepted: 06/03/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVES To evaluate diffusion tensor imaging (DTI) indices of the median nerve pre and postoperatively in patients with carpal tunnel syndrome (CTS) to determine whether indices acquired prior to surgery differ from those acquired postoperatively. METHODS Following IRB approval, ten patients with a diagnosis of CTS were prospectively recruited. Eight patients completed the study (seven women, one man). All had bilateral asymmetric symptoms, with subsequent carpal tunnel release on the more symptomatic side. DTI of both wrists were performed using single-shot spin-echo echo-planar imaging (TR/TE, 7,000/103 ms; b value 1,025 s/mm(2)) preoperatively, 6 weeks and 6 months after carpal tunnel release. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of the median nerve at the level of the distal radioulnar joint and pisiform were determined by one investigator blinded to clinical data, side, and time relative to surgery. RESULTS All patients had resolution of symptoms on the surgical side at 6 months. A significant increase in FA (p = 0.018) and decrease in ADC (p = 0.017) were found proximally at 6 months compared to baseline on the operative side. A significant increase in FA was observed on the operative side distally at 6 weeks (p = 0.012) and 6 months (p = 0.017). There was a significant difference in the percentage change in FA values from baseline to 6 months on the operative side in comparison with the non-operative side (p = 0.017). CONCLUSIONS A significant increase in FA and decrease in ADC of the median nerve are seen following decompression surgery in patients with CTS.
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Affiliation(s)
- Ali Naraghi
- Department of Medical Imaging, University of Toronto, Toronto Western Hospital, 399 Bathurst Street, Toronto, ON M5T 2S8, Canada.
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3-T MRI with diffusion tensor imaging and tractography of the median nerve. Eur Radiol 2013; 23:3124-30. [DOI: 10.1007/s00330-013-2955-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/23/2013] [Accepted: 05/24/2013] [Indexed: 11/27/2022]
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Miserocchi A, Cascardo B, Piroddi C, Fuschillo D, Cardinale F, Nobili L, Francione S, Russo GL, Cossu M. Surgery for temporal lobe epilepsy in children: relevance of presurgical evaluation and analysis of outcome. J Neurosurg Pediatr 2013; 11:256-67. [PMID: 23311387 DOI: 10.3171/2012.12.peds12334] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The authors' goal in this paper was to retrospectively evaluate the relevance of the presurgical workup and the postoperative outcome in children (< 15 years) who undergo surgery for temporal lobe epilepsy (TLE). METHODS The authors performed a retrospective analysis of 68 patients (43 boys and 25 girls) who underwent resection for TLE between 2001 and 2010 at a single center and had a minimum postoperative follow-up of 12 months. Presurgical investigations included full clinical evaluation, interictal electroencephalography (EEG), and MRI in all cases; cognitive evaluation in patients older than 5 years; scalp video-EEG in 46 patients; and invasive EEG in 3 patients. Clinical evaluation included a careful assessment of ictal semiology (based on anamnestic reports or video-EEG review), with particular attention to early signs and/or symptoms suggestive of temporal lobe origin of the seizure. Microsurgical resections were performed within the anatomical limits of the temporal lobe, and surgical specimens were processed for histological examination. Postoperative assessment of seizure outcome (Engel classification system) and cognitive performance was conducted at regular intervals. The effect on postoperative seizure outcome (good = Engel Class I; poor = Engel Classes II-IV) of several presurgical and surgical variables was investigated by bivariate statistical analysis. RESULTS All patients had at least 1 early sign or symptom suggesting a temporal lobe origin of their seizures. Lateralized interictal or ictal EEG abnormalities were seen in all patients, and they were localized to the temporal lobe in 45 patients. In all cases MRI demonstrated a structural abnormality. Surgery consisted of a tailored anterior temporal lobectomy in 64 patients and a neocortical lesionectomy in 4 patients. Postoperatively, 58 patients (85%) were in Engel Class I. Variables significantly associated with a poor outcome were preoperative sensory motor deficit (p = 0.019), mental retardation (p = 0.003), MRI abnormalities extending outside the temporal lobe (p = 0.0018), history of generalized seizures (p = 0.01) or status epilepticus (p = 0.008), unremarkable histology (p = 0.001), seizures immediately postoperatively (p = 0.00001), and ipsilateral epileptiform activity on postoperative EEG (p = 0.005). At postoperative neuropsychological assessment, the percentage of patients with a pathological score at the final visit invariably decreased compared with that at the preoperative evaluation in all considered cognitive domains. CONCLUSIONS Among the study population, a surgical selection based on a noninvasive evaluation was possible in most patients. The invaluable information resulting from the rigorous noninvasive electroclinical and neuroimaging evaluation can lead to excellent surgical results without the use of invasive, time-consuming, and expensive diagnostic tools. The potential reduction of invasiveness-related risks, complexity, and costs of presurgical investigations should hopefully allow for an increase in the number of children with TLE who will receive surgery, particularly in centers with limited technological resources.
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Affiliation(s)
- Anna Miserocchi
- C. Munari Epilepsy Surgery Centre, Department of Neuroscience, Niguarda Hospital, Milan, Italy
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Abstract
PURPOSE This study was conducted to assess the clinical relevance of diffusion tensor tractography (DTT) in pre- and post-operative evaluations of childhood epilepsy surgery. MATERIALS AND METHODS Seventy-two patients who received epilepsy surgery between March 2004 and July 2008 were retrospectively analyzed (M : F=40 : 32, ages of 3 months to 24 years, mean age=8.9 years). DTT was performed using a 3.0 T scanner and single-shot spin-echo echo-planar imaging with 32-different diffusion gradient directions. We reviewed the data focusing on the type of surgery, final pathological diagnosis, and how the DTT data were clinically used. RESULTS The most common form of childhood epilepsy surgery was complete resection of an epileptogenic lesion (n=52, 72.2%). The reported etiologies included cortical dysplasia (n=32, 44.4%), hippocampal sclerosis (n=9, 12.5%), brain tumors (n=7, 9.7%), and non-pathologic lesions (n=4, 5.6%) in the final diagnoses. Twenty-one dysplastic cortexes and four brain tumors involved an approximal relationship with the corticospinal tract (n=18), optic radiation (n=2), and arcuate fasciculus (n=5). Additionally, although DTT demonstrated white matter tracts clearly, DTT in the hippocampal sclerosis did not provide any additional information. In cases of callosotomy (n=18, 25%), post-operative DTT was utilized for the evaluation of complete resection in all patients. DTT information was not used in functional hemispherectomy (n=2, 2.8%). CONCLUSION Preoperatively, DTT was a useful technique in cases of cortical dysplasia and brain tumors, and in cases with callosotomy, postoperatively. DTT should be included among the routine procedures performed in management of epilepsy.
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Affiliation(s)
- Mi-Jung Lee
- Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Seoul, Korea
| | - Heung Dong Kim
- Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Joon Soo Lee
- Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Dong-Seok Kim
- Department of Pediatric Neurosurgery, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Seung-Koo Lee
- Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Seoul, Korea
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Hauptman JS, Mathern GW. Surgical treatment of epilepsy associated with cortical dysplasia: 2012 update. Epilepsia 2012; 53 Suppl 4:98-104. [PMID: 22946727 DOI: 10.1111/j.1528-1167.2012.03619.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cortical dysplasia is the most common etiology in children and the third most frequent finding in adults undergoing epilepsy neurosurgery. The new International League Against Epilepsy (ILAE) classification grades isolated cortical dysplasia into mild type I (cortical dyslamination), severe type II (dyslamination plus dysmorphic neurons and balloon cells), and dysplasia associated with other epileptogenic lesions (type III). Multilobar type II lesions present at an earlier age and with more severe epilepsy compared with focal type I abnormalities, often in the temporal lobe, and these findings are reflected in types and age of operations for cortical dysplasia. Presurgical evaluation of patients with epilepsy from cortical dysplasia can be challenging. Interictal and ictal scalp electroencephalography (EEG) accurately localizes cortical dysplasia with 50-66% accuracy. Structural magnetic resonance imaging (MRI) is negative in roughly 30% of cases, most often linked with mild type I cases. FDG-PET can be 80-90% accurate, but is not 100% sensitive. Chronic intracranial electrodes are used in about 50% of cases with cortical dysplasia, but often do not capture restricted ictal-onset zones. About 60% of patients with cortical dysplasia are seizure free after epilepsy neurosurgery, with much higher rates of becoming seizure free with complete (80%) compared with incomplete (20%) resections. The most common reason for incomplete resection is the risk of an unacceptable neurologic deficit. Future challenges include better tools in identifying subtle forms of type I cortical dysplasia, and development of adjunctive treatments from basic research for those undergoing incomplete resections.
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Affiliation(s)
- Jason S Hauptman
- Department of Neurosurgery, Mattel Children's Hospital, David Geffen School of Medicine, University of California, Los Angeles, California, USA
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Abstract
Focal cortical dysplasia is a malformation of cortical development, which is the most common cause of medically refractory epilepsy in the pediatric population and the second/third most common etiology of medically intractable seizures in adults.Both genetic and acquired factors are involved in the pathogenesis of cortical dysplasia. Numerous classifications of the complex structural abnormalities of focal cortical dysplasia have been proposed - from Taylor et al. in 1971 to the last modification of Palmini classification made by Blumcke in 2011. In general, three types of cortical dysplasia are recognized.Type I focal cortical dysplasia with mild symptomatic expression and late onset, is more often seen in adults, with changes present in the temporal lobe.Clinical symptoms are more severe in type II of cortical dysplasia usually seen in children. In this type, more extensive changes occur outside the temporal lobe with predilection for the frontal lobes.New type III is one of the above dysplasias with associated another principal lesion as hippocampal sclerosis, tumor, vascular malformation or acquired pathology during early life.Brain MRI imaging shows abnormalities in the majority of type II dysplasias and in only some of type I cortical dysplasias.THE MOST COMMON FINDINGS ON MRI IMAGING INCLUDE: focal cortical thickening or thinning, areas of focal brain atrophy, blurring of the gray-white junction, increased signal on T2- and FLAIR-weighted images in the gray and subcortical white matter often tapering toward the ventricle. On the basis of the MRI findings, it is possible to differentiate between type I and type II cortical dysplasia. A complete resection of the epileptogenic zone is required for seizure-free life. MRI imaging is very helpful to identify those patients who are likely to benefit from surgical treatment in a group of patients with drug-resistant epilepsy.However, in type I cortical dysplasia, MR imaging is often normal, and also in both types the lesion seen on MRI may be smaller than the seizure-generating region seen in the EEG. The abnormalities may also involve vital for life brain parts, where curative surgery will not be an option. Therefore, other diagnostic imaging techniques such as FDG PET, MEG, DTI and intra-cranial EEG are widely used to establish the diagnosis and to decide on management.With advances in both genetics and neuroimaging, we may develop a better understanding of patients with drug-resistant epilepsy, which will help us to provide more successful pharmacological and/or surgical treatment in the future.
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Affiliation(s)
- Joanna Kabat
- Department of Diagnostic Imaging, Mazowiecki Regional Hospital in Siedlce, Siedlce, Poland
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Development and dysgenesis of the cerebral cortex: malformations of cortical development. Neuroimaging Clin N Am 2012; 21:483-543, vii. [PMID: 21807310 DOI: 10.1016/j.nic.2011.05.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The cerebral cortex develops in several stages from a pseudostratified epithelium at 5 weeks to an essentially complete cortex at 47 weeks. Cortical connectivity starts with thalamocortical connections in the 3rd trimester only and continues until well after birth. Vascularity adapts to proliferation and connectivity. Malformations of cortical development are classified into disorders of specification, proliferation/apoptosis, migration, and organization. However, all processes are intermingled, as for example a dysplastic cell may migrate incompletely and not connect appropriately. However, this classification is convenient for didactic purposes as long as the complex interactions between the different processes are kept in mind.
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Fellah S, Callot V, Viout P, Confort-Gouny S, Scavarda D, Dory-Lautrec P, Figarella-Branger D, Cozzone PJ, Girard N. Epileptogenic brain lesions in children: the added-value of combined diffusion imaging and proton MR spectroscopy to the presurgical differential diagnosis. Childs Nerv Syst 2012; 28:273-82. [PMID: 22038149 DOI: 10.1007/s00381-011-1604-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 09/28/2011] [Indexed: 11/27/2022]
Abstract
PURPOSE Focal cortical dysplasia (FCD), dysembryoplastic neuroepithelial tumors (DNTs), and gangliogliomas (GGs) share many clinical features, and the presurgical differential diagnosis of these lesions using conventional magnetic resonance imaging (MRI) is challenging in some cases. The purpose of this work was thus to evaluate the capacity of diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy (MRS) to distinguish each lesion from the others. METHODS Seventeen children (mean age 9.0 ± 4.7 years), who had been referred for epilepsy associated with a brain tumor and operated, were selected. Preoperative MRI examinations were performed on a 1.5 T system and included anatomical images [T2-weighted, fluid-attenuated inversion recovery (FLAIR) and T1 pre- and post-injection images] as well as DWI and MRS [echo time (TE) = 30 and 135 ms]. Apparent diffusion coefficient (ADC) values were calculated in the lesion and healthy control. MRS relative quantification consisted in normalizing each metabolite by the sum (S) of all metabolites (S(TE=135 ms) = NAA+Cr+Cho; S(TE=30 ms) = NAA+Cr+Cho+Glx+mI). Univariate and multivariate analyses were performed in order to determine which criteria could differentiate the different epileptogenic brain lesions. RESULTS When taken alone, none of the MRI parameters was able to distinguish each disease from the others. Conventional MRI failed classifying two patients. When adding ADC to the linear discriminant analysis (LDA), one patient was still misclassified. Complete separation of the three groups was possible when combining conventional MRI, diffusion, and MRS either at long or short TE. CONCLUSION This study shows the added-value of multimodal MRI and MRS in the presurgical diagnosis of epileptogenic brain lesions in children.
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Affiliation(s)
- Slim Fellah
- Centre de Résonance Magnétique Biologique et Médicale, Aix-Marseille University/CNRS, Marseille, France.
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Hauptman JS, Mathern GW. Epilepsy neurosurgery in children. HANDBOOK OF CLINICAL NEUROLOGY 2012; 108:881-95. [PMID: 22939072 DOI: 10.1016/b978-0-444-52899-5.00034-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Affiliation(s)
- Jason S Hauptman
- Department of Neurosurgery, University of California, Los Angeles, CA, USA
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Abstract
OBJECTIVE Dysplasia at the bottom of a sulcus is a subtle but distinct malformation of cortical development relevant to epilepsy. The purpose of this study was to review the imaging features important to the clinical diagnosis of this lesion. MATERIALS AND METHODS All cases recognized as typical bottom-of-sulcus dysplasia in our comprehensive epilepsy program over the period 2002-2007 were included in the study. RESULTS In the 20 cases recognized, three major features were identified: cortical thickening at the bottom of a sulcus; a funnel-shaped extension of the lesion toward the ventricular surface, commonly with abnormal signal intensity; and an abnormal gyral pattern related to the bottom-of-sulcus dysplasia, sometimes with a puckered appearance. The pathologic features of the resected lesions were typical of focal cortical dysplasia. CONCLUSION Bottom-of-sulcus dysplasia is a distinctive malformation of cortical development that can be diagnosed on the basis of imaging characteristics. Reliable identification of this type of malformation of cortical development is difficult but clinically important because the lesion appears to be highly epileptogenic and because the prognosis for seizure control is excellent after focal resection.
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Säisänen L, Könönen M, Julkunen P, Määttä S, Vanninen R, Immonen A, Jutila L, Kälviäinen R, Jääskeläinen JE, Mervaala E. Non-invasive preoperative localization of primary motor cortex in epilepsy surgery by navigated transcranial magnetic stimulation. Epilepsy Res 2010; 92:134-44. [DOI: 10.1016/j.eplepsyres.2010.08.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 08/17/2010] [Accepted: 08/22/2010] [Indexed: 11/29/2022]
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Phi JH, Paeng JC, Lee HS, Wang KC, Cho BK, Lee JY, Park SH, Lee J, Lee DS, Kim SK. Evaluation of focal cortical dysplasia and mixed neuronal and glial tumors in pediatric epilepsy patients using 18F-FDG and 11C-methionine pet. J Nucl Med 2010; 51:728-34. [PMID: 20395328 DOI: 10.2967/jnumed.109.070920] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED Focal cortical dysplasia (FCD) and mixed neuronal and glial tumors share many clinical characteristics; therefore, the presurgical differential diagnosis of these diseases using MRI is difficult in some cases. The aim of this study was to determine whether (11)C-methionine PET, compared with (18)F-FDG PET, was useful for the evaluation of these diseases. METHODS The clinical and imaging data of 30 pediatric lesional epilepsy patients pathologically diagnosed with FCD, dysembryoplastic neuroepithelial tumor (DNT), or ganglioglioma were reviewed. Eleven patients had FCD, 8 patients had a DNT, and 11 patients had a ganglioglioma. (18)F-FDG and (11)C-methinine PET scans were obtained from 25 patients and 15 patients, respectively. Visual grading analysis and quantitative assessment of (18)F-FDG and (11)C-methionine PET, represented as a lesion-to-gray matter ratio (LGR), were performed. RESULTS In the visual grading analysis, both (18)F-FDG PET and (11)C-methionine PET detected a significant difference among the 3 disease groups (P = 0.033 and P = 0.016, respectively), but discrimination of FCD from mixed neuronal and glial tumors was possible only with (11)C-methionine PET. The mean LGR of (18)F-FDG PET was 0.502 +/- 0.119 for FCD, 0.631 +/- 0.107 for DNTs, and 0.620 +/- 0.196 for gangliogliomas; there was no significant difference in LGR among the groups (P = 0.111). However, the mean LGR of (11)C-methionine PET was 1.078 +/- 0.182 for FCD, 1.564 +/- 0.368 for DNT, and 2.114 +/- 0.723 for gangliogliomas; there was a significant difference in LGR among the groups (P = 0.014). Post hoc analysis revealed that the LGR of FCD was significantly different from that of DNTs and gangliogliomas. The mean LGR value of DNTs fell between those of FCD and gangliogliomas. CONCLUSION Although (18)F-FDG plays a major role in the preoperative work-up of epilepsy surgery patients, it appears from this study that (18)F-FDG does not contribute to the differential diagnosis and that another tracer such as (11)C-methinine is required. (11)C-methinine PET results correlated well with the pathologic spectrum in pediatric lesional epilepsy patients.
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Affiliation(s)
- Ji Hoon Phi
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
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Mathern GW. Challenges in the surgical treatment of epilepsy patients with cortical dysplasia. Epilepsia 2009; 50 Suppl 9:45-50. [PMID: 19761453 DOI: 10.1111/j.1528-1167.2009.02294.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cortical dysplasia (CD) is the most common malformation of cortical development in epilepsy surgery patients. Patients with mild Palmini type I CD represent about 50% of the surgical cases, and these lesions tend to occur most often in the temporal lobe, often associated with hippocampal sclerosis. By comparison, patients with severe type II CD present at younger ages, often with multilobar extratemporal lesions, and more aggressive seizures. The presurgical evaluation in CD patients can be challenging, as no single test is 100% accurate. Based on retrospective cohort studies, the accuracy of investigations are: interictal scalp electroencephalography (EEG), 50%; ictal scalp EEG, 65%; magnetic resonance imaging (MRI), 66%; fluorodeoxyglucose-positron emission tomography (FDG-PET), 81%; and ictal single photon emission computed tomography (SPECT), 57%. Intracranial electrodes are used in about 50% of patients with CD. Contemporary series report that 62% of patients with CD are seizure free after resective neurosurgery, with higher rates for complete (77%) compared with incomplete (20%) removal of the lesion. Morbidity (<3%) and mortality (0.2%) are low for patients with CD undergoing epilepsy neurosurgery. Future challenges include the noninvasive identification of patients with CD with 100% accuracy, evaluation of long-term outcomes in surgical patients, and devising new treatments based on a better understanding of the neurobiology leading to seizures in CD tissue.
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Affiliation(s)
- Gary W Mathern
- Department of Neurosurgery, The Brain Research Institute and The Mental Retardation Research Center, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
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Bhatia S, Ragheb J, Johnson M, Oh S, Sandberg DI, Lin WC. The role of optical spectroscopy in epilepsy surgery in children. Neurosurg Focus 2009; 25:E24. [PMID: 18759626 DOI: 10.3171/foc/2008/25/9/e24] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Surgery is an important therapeutic modality for pediatric patients with intractable epilepsy. However, existing imaging and diagnostic technologies such as MR imaging and electrocochleography (ECoG) do not always effectively delineate the true resection margin of an epileptic cortical lesion because of limitations in their sensitivity. Optical spectroscopic techniques such as fluorescence and diffuse reflectance spectroscopy provide a nondestructive means of gauging the physiological features of the brain in vivo, including hemodynamics and metabolism. In this study, the authors investigate the feasibility of using combined fluorescence and diffuse reflectance spectroscopy to assist epilepsy surgery in children. METHODS In vivo static fluorescence and diffuse reflectance spectra were acquired from the brain in children undergoing epilepsy surgery. Spectral measurements were obtained using a portable spectroscopic system in conjunction with a fiber optic probe. The optical investigations were conducted at the normal and abnormal cortex as defined by intraoperative ECoG and preoperative imaging studies. Biopsy samples were taken from the investigated sites located within the zone of resection. The optical spectra were classified into multiple subsets in accordance with the ECoG and histological study results. The authors used statistical comparisons between 2 given data subsets to identify unique spectral features. Empirical discrimination algorithms were developed using the identified spectral features to determine if the objective of the study was achieved. RESULTS Fifteen pediatric patients were enrolled in this pilot study. Elevated diffuse reflectance signals between 500 and 600 nm and/or between 650 and 850 nm were observed commonly in the investigated sites with abnormal ECoG and/or histological features in 10 patients. The appearance of a fluorescent peak at 400 nm was observed in both normal and abnormal cortex of 5 patients. These spectral alterations were attributed to changes in morphological and/or biochemical characteristics of the epileptic cortex. The sensitivities and specificities of the empirical discrimination algorithms, which were constructed using the identified spectral features, were all > 90%. CONCLUSIONS The results of this study demonstrate the feasibility of using static fluorescence and diffuse reflectance spectroscopy to differentiate normal from abnormal cortex on the basis of intraoperative assessment of ECoG and histological features. It is therefore possible to use fluorescence and diffuse reflectance spectroscopy as an aid in epilepsy surgery.
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Affiliation(s)
- Sanjiv Bhatia
- Brain Institute, Miami Children's Hospital, Miami, Florida 33131, USA
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Balaji R, Ramachandran K. Imaging of desmoplastic infantile ganglioglioma: a spectroscopic viewpoint. Childs Nerv Syst 2009; 25:497-501. [PMID: 19139903 DOI: 10.1007/s00381-008-0786-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 11/20/2008] [Indexed: 10/21/2022]
Abstract
PURPOSE Desmoplastic infantile gangliogliomas (DIG) are rare benign intracranial neoplasms of early childhood with involvement of superficial cerebral cortex and leptomeninges. The purpose of the study was to determine the alterations in metabolite ratios occurring in the neoplasm and combine with magnetic resonance (MR) imaging features to narrow down the diagnosis. METHODS MR imaging sequences include T1- and T2-weighted sequences, fluid-attenuated inversion recovery sequences, and post-gadolinium-contrast T1-weighted imaging. Single-voxel short TE (1)H MR spectroscopy was used to study the changes in metabolite ratios in the tumor. RESULTS Comparison of metabolite ratios between normal brain tissue and tumor-affected region showed lower N-acetyl aspartate to creatine (Cr; 1.58 vs.1.28), higher choline to Cr (0.82 vs.2.03), and no significant change in myo-inositol to Cr (0.42 vs.0.39). CONCLUSION MR spectroscopy and imaging provide valuable information in the diagnosis of DIG.
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Affiliation(s)
- Ravikanth Balaji
- Imageology Division, Regional Cancer Center, Medical College PO, Trivandrum, Kerala, India.
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Approach to pediatric epilepsy surgery: State of the art, Part II: Approach to specific epilepsy syndromes and etiologies. Eur J Paediatr Neurol 2009; 13:115-27. [PMID: 18590975 DOI: 10.1016/j.ejpn.2008.05.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 03/13/2008] [Accepted: 05/08/2008] [Indexed: 11/23/2022]
Abstract
The second of this 2-part review depicts the specific approach to the common causes of pediatric refractory epilepsy amenable to surgery. These include tumors, malformations due to abnormal cortical development, vascular abnormalities and certain epileptic syndromes. Seizure freedom rates are high (usually 60-80%) following tailored focal resection, lesionectomy, and hemispherectomy. However, in patients in whom the epileptogenic zone overlaps with unresectable eloquent cortex, and in certain epileptic syndromes, seizure freedom may not be achievable. In such cases, palliative procedures such as callosotomy, multiple subpial transections and vagus nerve stimulation can achieve reduction in seizure severity but rarely seizure freedom. Integration of the new imaging techniques and the concepts of neuronal plasticity, the epileptogenic lesion, the ictal onset, symptomatogenic, irritative, and epileptogenic zones is an expanding and dynamic process that will allow us, in the future, to better decide on the surgical approach of choice and its timing.
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Lerner JT, Salamon N, Hauptman JS, Velasco TR, Hemb M, Wu JY, Sankar R, Donald Shields W, Engel J, Fried I, Cepeda C, Andre VM, Levine MS, Miyata H, Yong WH, Vinters HV, Mathern GW. Assessment and surgical outcomes for mild type I and severe type II cortical dysplasia: a critical review and the UCLA experience. Epilepsia 2009; 50:1310-35. [PMID: 19175385 DOI: 10.1111/j.1528-1167.2008.01998.x] [Citation(s) in RCA: 269] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Recent findings on the clinical, electroencephalography (EEG), neuroimaging, and surgical outcomes are reviewed comparing patients with Palmini type I (mild) and type II (severe) cortical dysplasia. Resources include peer-reviewed studies on surgically treated patients and a subanalysis of the 2004 International League Against Epilepsy (ILAE) Survey of Pediatric Epilepsy Surgery. These sources were supplemented with data from University of California, Los Angeles (UCLA). Cortical dysplasia is the most frequent histopathologic substrate in children, and the second most common etiology in adult epilepsy surgery patients. Cortical dysplasia patients present with seizures at an earlier age than other surgically treated etiologies, and 33-50% have nonlocalized scalp EEG and normal magnetic resonance imaging (MRI) scans. 2-((18)F)Fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) is positive in 75-90% of cases. After complete resection, 80% of patients are seizure free compared with 20% with incomplete resections. Compared with type I, patients with type II cortical dysplasia present at younger ages, have higher seizure frequencies, and are extratemporal. Type I dysplasia is found more often in adult patients in the temporal lobe and is often MRI negative. These findings identify characteristics of patients with mild and severe cortical dysplasia that define surgically treated epilepsy syndromes. The authors discuss future challenges to identifying and treating medically refractory epilepsy patients with cortical dysplasia.
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Affiliation(s)
- Jason T Lerner
- Department of Pediatric Neurology, University of California, Los Angeles, California, USA
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Rastogi S, Lee C, Salamon N. Neuroimaging in pediatric epilepsy: a multimodality approach. Radiographics 2008; 28:1079-95. [PMID: 18635630 DOI: 10.1148/rg.284075114] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Pediatric patients with intractable epilepsy represent a challenging clinical population. However, recent advances in neuroimaging with a multimodality imaging approach that combines fluorine 18 fluorodeoxyglucose positron emission tomography, magnetoencephalography, diffusion tensor imaging, and magnetic source imaging with conventional magnetic resonance imaging continue to improve diagnosis and treatment in affected patients. These advances are increasing the understanding of the underlying disease process and improving the ability to noninvasively detect epileptogenic foci that in the past went undetected and whose accurate localization is crucial for a good outcome following surgical resection.
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Affiliation(s)
- Sachin Rastogi
- Department of Radiological Sciences, David Geffen School of Medicine at UCLA, 10833 Le Conte Ave, Room BL-428/CHS, Los Angeles, CA 90095-1721, USA.
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Balaji R, Ramachandran K, Krishnakumar A, Venugopal M. MR and CT Evaluation of Dysembryoplastic Neuroepithelial Tumor. Neuroradiol J 2008; 21:667-71. [DOI: 10.1177/197140090802100510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 07/26/2008] [Indexed: 11/16/2022] Open
Abstract
A 33-year-old man presented with a long history of intractable partial seizures with the first episode at the age of 18 years. The seizure frequency had increased in the recent past. CT imaging revealed a low attenuation lesion in the left frontal cortex with calvarial scalloping. MR imaging revealed a heterogeneous signal intensity lesion with involvement of the cortex and the sub-cortical white matter. In dysembryoplastic neuroepithelial tumor the neoplastic elements adjacent to the cortex might cause disorganization of cortical layers in the developmental stage leading to cortical dysplasia. Architectural dysplasia is characterized by cortical thickening and ectopic neurons in the white matter. MR imaging features reflect the characteristics of cortical dysplasia and ectopic neurons in the sub-cortical white matter.
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Affiliation(s)
- R. Balaji
- Imageology Division, Regional Cancer Centre, Trivandrum; Kerala, India
| | - K. Ramachandran
- Imageology Division, Regional Cancer Centre, Trivandrum; Kerala, India
| | - A.S. Krishnakumar
- Imageology Division, Regional Cancer Centre, Trivandrum; Kerala, India
| | - M. Venugopal
- Imageology Division, Regional Cancer Centre, Trivandrum; Kerala, India
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Vazquez E, Mayolas N. Developmental abnormalities of temporal lobe in children. Semin Ultrasound CT MR 2008; 29:15-39. [PMID: 18383905 DOI: 10.1053/j.sult.2007.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A review of neuroimaging findings in diverse pathologies involving the temporal lobe in children is undertaken. Illustrative images of the developmental disorders that may cause temporal epilepsy in the pediatric context are provided. Brain malformations associated with hippocampal dysgenesis and related conditions such as epilepsy-associated tumors will be discussed with representative examples. Neurocutaneous syndromes that can involve the temporal lobe producing epilepsy or learning defects will be also discussed. Some other miscellaneous disorders occurring preferentially in the pediatric age such as hippocampal damage secondary to hypoxia or radiotherapy will be briefly exposed at the end of the article.
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Affiliation(s)
- Elida Vazquez
- Department of Pediatric Radiology, Hospital Universitario Vall d'Hebron, Universidad Autonoma de Barcelona, Barcelona, Spain.
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Present status of surgical intervention for children with intractable seizures. Curr Neurol Neurosci Rep 2008; 8:123-9. [DOI: 10.1007/s11910-008-0020-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Wehner T, Lüders H. Role of neuroimaging in the presurgical evaluation of epilepsy. J Clin Neurol 2008; 4:1-16. [PMID: 19513318 PMCID: PMC2686888 DOI: 10.3988/jcn.2008.4.1.1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Accepted: 02/14/2008] [Indexed: 11/17/2022] Open
Abstract
A significant minority of patients with focal epilepsy are candidates for resective epilepsy surgery. Structural and functional neuroimaging plays an important role in the presurgical evaluation of theses patients. The most frequent etiologies of pharmacoresistant epilepsy in the adult population are mesial temporal sclerosis, malformations of cortical development, cavernous angiomas, and low-grade neoplasms. High-resolution multiplanar magnetic resonance imaging (MRI) with sequences providing T1 and T2 contrast is the initial imaging study of choice to detect these epileptogenic lesions. The epilepsy MRI protocol can be individually tailored when considering the patient's clinical and electrophysiological data. Metabolic imaging techniques such as positron emission tomography (PET) and single photon emission tomography (SPECT) visualize metabolic alterations of the brain in the ictal and interictal states. These techniques may have localizing value in patients with a normal MRI scan. Functional MRI is helpful in non-invasively identifying areas of eloquent cortex.Developments in imaging technology and digital postprocessing may increase the yield for imaging studies to detect the epileptogenic lesion and to characterize its connectivity within the epileptic brain.
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Affiliation(s)
- Tim Wehner
- Epilepsy Center-S51, Neurological Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195 USA
| | - Hans Lüders
- Epilepsy Center-S51, Neurological Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195 USA
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Kabakci N, Gürses B, Firat Z, Bayram A, Uluğ AM, Kovanlikaya A, Kovanlikaya I. Diffusion tensor imaging and tractography of median nerve: normative diffusion values. AJR Am J Roentgenol 2007; 189:923-7. [PMID: 17885066 DOI: 10.2214/ajr.07.2423] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purposes of this study were to visualize the human median nerve on diffusion tensor imaging and to determine the normal fractional anisotropy (FA) value and apparent diffusion coefficient (ADC) of the normal median nerve. SUBJECTS AND METHODS The wrists of 20 healthy volunteers and of two patients with carpel tunnel syndrome were examined with a 3-T MRI system with a standard eight-channel sensitivity-encoding head coil. Diffusion tensor imaging was performed with a spin-echo echo-planar sequence. A T1-weighted sequence was performed for anatomic reference. After tractography, the FA value and ADC of the whole nerve were calculated automatically. Manual focal measurements also were obtained at the levels of the flexor retinaculum, wrist, and forearm. RESULTS We visualized the median nerve with MR diffusion tensor tractography and followed the nerve for approximately 77.5 mm. We found the normative diffusion values of the median nerve were an FA of 0.709 +/- 0.046 (SD) and an ADC of 1.016 +/- 0.129 x 10(-3) mm2/s. There was a statistically significant difference between the FA values obtained at the level of the flexor retinaculum and the values obtained from the other parts of the median nerve (p < 0.0001). We found a decrease in FA value (p < 0.01) and an increase in ADC (p < 0.05) with advancing age. CONCLUSION The normative diffusion values of the human median nerve can be used as a reference in evaluation, diagnosis, and follow-up of entrapment, trauma, and regeneration of the median nerve.
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Affiliation(s)
- Neslihan Kabakci
- Department of Radiology, Yeditepe University Hospital, Devlet Yolu Ankara Cad. 102-104, 34752 Kozyataği, Istanbul, Turkey.
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Bulakbasi N, Kocaoglu M, Sanal TH, Tayfun C. Dysembryoplastic neuroepithelial tumors: proton MR spectroscopy, diffusion and perfusion characteristics. Neuroradiology 2007; 49:805-12. [PMID: 17632714 DOI: 10.1007/s00234-007-0263-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Accepted: 05/29/2007] [Indexed: 10/23/2022]
Abstract
INTRODUCTION We describe the magnetic resonance (MR) imaging characteristics of dysembryoplastic neuroepithelial tumors (DNT) and discuss their differential diagnosis. MATERIAL AND METHODS Proton MR spectroscopy (TE 30 and 136 ms), diffusion-weighted and perfusion images were retrospectively evaluated in 22 patients with pathologically proven DNT (17 male and 5 female, mean age 18.7 years) and 14 control subjects (10 male and 4 female, mean age 16.9 years). The results from the DNT patients and from the control subjects were compared using an independent sample t-test and the degree of correlation was tested by Pearson's correlation. RESULTS All DNTs were solitary and in a supratentorial cortical or subcortical location (ten temporal, eight frontal and four parietal). They had low-signal on T1-weighted images and high-signal on T2-weighted images without a prominent mass effect. Additionally a cystic appearance (six patients, 27.3%), cortical dysplasia (six patients, 27.3%) and contrast enhancement (four patients, 18.2%) were also noted. No significant differences were detected in NAA/Cho, NAA/Cr, NAA/Cho+Cr or Cho/Cr ratios between DNT and normal brain. DNTs had a significantly higher mI/Cr ratio and apparent diffusion coefficient (ADC) values and lower cerebral blood values than normal parenchyma (P < 0.001). ADC had the highest correlation with the diagnosis of DNT (r = 0.996) followed by relative cerebral blood volume (rCBV) (r = -0.883) and mI/Cr ratio (r = 0.663). CONCLUSION Proton MR spectroscopy, diffusion-weighted and perfusion imaging characteristics of DNTs provide additional information to their MR imaging findings. The MR spectrum showing a slight increase in mI/Cr ratio, and higher ADC and lower rCBV values than normal parenchyma help to differentiate DNTs from other cortical tumors, which had higher rCBV and lower ADC values than DNTs.
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Affiliation(s)
- Nail Bulakbasi
- Department of Radiology, Military Medical Faculty, Gulhane Military Medical Academy, Etlik, 06018 Ankara, Turkey.
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