Stereo-EEG features of temporal and frontal lobe seizures with loss of consciousness.

The loss of consciousness (LOC) during seizures is one of the most striking features that significantly impact the quality of life, even though the neuronal network involved is not fully comprehended. We analyzed the intracerebral patterns in patients with focal drug-resistant epilepsy, both with and without LOC. We assessed the localization, lateralization, stereo electroencephalography (SEEG) patterns, seizure duration, and the quantification of contacts exhibiting electrical discharge. The degree of LOC was quantified using the Consciousness Seizure Scale. Thirteen patients (40 seizures) with focal drug-resistant epilepsy underwent SEEG. In cases of temporal lobe epilepsy (TLE, 6 patients and 15 seizures), LOC occurred more frequently in seizures with mesial rather than lateral temporal lobe onset. On the other hand, in cases of frontal lobe epilepsy (7 patients; 25 seizures), LOC was associated with pre-frontal onset, a higher number of contacts with epileptic discharge compared to the onset count and longer seizure durations. Our study revealed distinct characteristics during LOC depending on the epileptogenic zone. For temporal lobe seizures, LOC was associated with mesial seizure onset, whereas in frontal lobe epilepsy, seizure with LOC has a significant increase in contact showing epileptiform discharge and a pre-frontal onset. This phenomenon may be correlated with the broad neural network required to maintain consciousness, which can be affected in different ways, resulting in LOC.

[Benefit of surgery in a case of negative motor focal epileptic seizures secondary to parietal cortical dysplasia]. / Beneficio de la cirugía en un caso de crisis epilépticas focales motoras negativas secundarias a displasia cortical parietal.

Focal atonic seizures are recognized rarely as ictal phenomena, they can correspond to both generalized epilepsy and focal epilepsy. The areas of the brain involved in the management of this type of seizure are: the negative motor area and the primary motor and primary somatosensory cortices, although the neurophysiology that generates them is still unclear. We present the case of a patient with focal atonic seizures in the left upper limb, refractory to drug treatment. Neuroimaging was performed, a parietal cortical lesion was diagnosed. A scalp Video EEG and then a Stereo EEG was performed, defining the epileptogenic area and its relationship with eloquent areas. Surgical resection of the lesion was performed, achieving complete seizure control.

Las crisis atónicas focales son poco reconocidas como fenómenos ictales, pueden corresponder tanto a una epilepsia generalizada como a una epilepsia focal. Las áreas del cerebro implicadas en la gestión de este tipo de crisis son: el área motora negativa y las cortezas motora primaria y somatosensitiva primaria, aunque aún la neurofisiología que las genera no está aclarada. Presentamos el caso de un paciente con crisis atónicas focales farmacorresistentes en miembro superior izquierdo. Se realizó resonancia de cerebro con diagnóstico de displasia cortical parietal, se monitoreó con video EEG de scalp y luego a video EEG con electrodos profundos. Se definieron el área epileptógena y su relación con áreas elocuentes, se realizó resección quirúrgica de la lesión, logrando el control completo de las crisis.

NORHA: A NORmal Hippocampal Asymmetry Deviation Index Based on One-Class Novelty Detection and 3D Shape Features.

Radiologists routinely analyze hippocampal asymmetries in magnetic resonance (MR) images as a biomarker for neurodegenerative conditions like epilepsy and Alzheimer's Disease. However, current clinical tools rely on either subjective evaluations, basic volume measurements, or disease-specific models that fail to capture more complex differences in normal shape. In this paper, we overcome these limitations by introducing NORHA, a novel NORmal Hippocampal Asymmetry deviation index that uses machine learning novelty detection to objectively quantify it from MR scans. NORHA is based on a One-Class Support Vector Machine model learned from a set of morphological features extracted from automatically segmented hippocampi of healthy subjects. Hence, in test time, the model automatically measures how far a new unseen sample falls with respect to the feature space of normal individuals. This avoids biases produced by standard classification models, which require being trained using diseased cases and therefore learning to characterize changes produced only by the ones. We evaluated our new index in multiple clinical use cases using public and private MRI datasets comprising control individuals and subjects with different levels of dementia or epilepsy. The index reported high values for subjects with unilateral atrophies and remained low for controls or individuals with mild or severe symmetric bilateral changes. It also showed high AUC values for discriminating individuals with hippocampal sclerosis, further emphasizing its ability to characterize unilateral abnormalities. Finally, a positive correlation between NORHA and the functional cognitive test CDR-SB was observed, highlighting its promising application as a biomarker for dementia.

Vigabatrin-associated brain abnormalities on MRI and other neurological symptoms in patients with West syndrome.

OBJECTIVES: Report a series of children with West syndrome (WS) treated with vigabatrin (VGB) who developed characteristic MRI alterations. In the majority, these adverse events were asymptomatic; however, some of the patients developed movement disorders and acute encephalopathy. METHODS: This is a retrospective analysis of our epilepsy clinical and EEG database of 288 patients with WS seen between 2014 and 2020. All patients who received VGB alone or with concomitant therapies, such as adrenocorticotropic hormone (ACTH), high-dose oral corticosteroids, ketogenic diet, valproate, levetiracetam, or topiramate, were evaluated. RESULTS: In 44 of 288 patients with WS receiving VGB, MRI findings compatible with VGB-associated brain abnormalities were identified; median age at diagnosis was 6.29 months (range, 2 weeks to 11 months). The etiology of WS with vigabatrin-associated brain abnormalities on MRI (VABAM) was unknown in 22 (52.27%), genetic in seven (15.9%), genetic-structural in three (6.8%), structural malformative in three others (6.8%), and structural acquired in eight patients (18.2%). Vigabatrin-associated brain abnormalities on MRI was asymptomatic in 25 of 44 patients. Ten of 44 (22.7%) infants were reported to have had a movement disorder (choreoathetosis, dystonic posturing). Nine of 42 infants exhibited progressive psychomotor deterioration associated with signs and symptoms of encephalopathy. CONCLUSION: MRI abnormalities were observed in infants treated with VGB and they appeared to be dose dependent. In our study common locations for MRI abnormalities included globi pallidi and brainstem, followed by thalami and dentate nuclei. Risk factors for the development of VABAM may include age younger than 11 months and higher VGB dose of VGB (>165 mg/kg/day). Vigabatrin-associated brain abnormalities on MRI usually resolved following VGB discontinuation, probably after a period of 3 months.

Influence of accessory sulci of the frontoparietal operculum on gray matter quantification.

Introduction: The perisylvian region is the cortical core of language and speech. Several accessory sulci have been described in this area, whose presence could modify the results of the automatic quantification of gray matter by popularly used software. This study aimed to assess the expression of accessory sulci in the frontoparietal operculum (FPO) and to evaluate their influence on the gray matter volume estimated by an automatic parcellation of cortical gyri and sulci. Methods: Brain MRI scans of 100 healthy adult volunteers were visually analyzed. The existence of the triangular and diagonal sulci, and the number of accessory sulci in the frontoparietal operculum, were assessed on T1 images. Also, the gray matter volume of gyri and sulci was quantified by an automatized parcellation method. Interhemispheric differences in accessory sulci were evaluated with Chi-square and Wilcoxon paired tests. The effects of the hemisphere, sex, age, total intracranial volume, and accessory sulci on morphometric variables were assessed by linear models. Results: These sulci were found in more than half of the subjects, mostly in the left hemisphere, and showed a significant effect on the gray matter content of the FPO. In particular, the volume of the inferior frontal sulcus, pars opercularis of the inferior frontal gyrus, horizontal ramus of the lateral sulcus, angular gyrus, and postcentral gyrus showed a significant influence on the presence of accessory sulci. Discussion: The prevalence of tertiary sulci in the FPO is high, although their meaning is not yet known. Therefore, they should be considered to reduce the risk of misclassifications of normal variation.

Utility of paramagnetic rim lesions on 1.5-T susceptibility phase imaging for the diagnosis of pediatric multiple sclerosis.

BACKGROUND: Studies have suggested that paramagnetic rim lesions on 7-tesla (T) and 3-T susceptibility-based brain MRI are specific features of multiple sclerosis (MS) lesions in adults. OBJECTIVE: The aim of this study was to investigate whether the presence of paramagnetic rim lesions on 1.5-T phase images can help discriminate pediatric patients with MS from those with other demyelinating diseases. MATERIALS AND METHODS: In this retrospective study we reviewed brain MRIs performed on 1.5-T scanners that included susceptibility-weighted imaging (SWI) sequences with phase images in children younger than 18 years diagnosed with MS and other acquired demyelinating syndromes. In each case, five white matter lesions were selected using T2/fluid-attenuated inversion recovery images for further paramagnetic rim evaluation on SWI. Two researchers performed independent assessments of the presence of paramagnetic rim lesions. Discrepancies between them were settled by consensus, with input from a senior neuroradiologist. RESULTS: We included 13 children diagnosed with MS and 16 children diagnosed with non-MS demyelinating diseases and analyzed a total of 132 focal white matter lesions. Seventy-one percent of the lesions in the MS group had paramagnetic rims, while none of the lesions in the non-MS group had rims. All but one of the children with MS had at least one lesion with a paramagnetic rim. The presence of one lesion with a paramagnetic rim on 1.5-T phase-contrast images resulted in 70% sensitivity and 100% specificity for MS. CONCLUSION: Paramagnetic rim lesions detected on 1.5-T phase-contrast MR images can help discriminate MS from other acquired demyelinating syndromes in the pediatric population.

Diagnostic Performance of MRI Volumetry in Epilepsy Patients With Hippocampal Sclerosis Supported Through a Random Forest Automatic Classification Algorithm.

Introduction: Several methods offer free volumetry services for MR data that adequately quantify volume differences in the hippocampus and its subregions. These methods are frequently used to assist in clinical diagnosis of suspected hippocampal sclerosis in temporal lobe epilepsy. A strong association between severity of histopathological anomalies and hippocampal volumes was reported using MR volumetry with a higher diagnostic yield than visual examination alone. Interpretation of volumetry results is challenging due to inherent methodological differences and to the reported variability of hippocampal volume. Furthermore, normal morphometric differences are recognized in diverse populations that may need consideration. To address this concern, we highlighted procedural discrepancies including atlas definition and computation of total intracranial volume that may impact volumetry results. We aimed to quantify diagnostic performance and to propose reference values for hippocampal volume from two well-established techniques: FreeSurfer v.06 and volBrain-HIPS. Methods: Volumetry measures were calculated using clinical T1 MRI from a local population of 61 healthy controls and 57 epilepsy patients with confirmed unilateral hippocampal sclerosis. We further validated the results by a state-of-the-art machine learning classification algorithm (Random Forest) computing accuracy and feature relevance to distinguish between patients and controls. This validation process was performed using the FreeSurfer dataset alone, considering morphometric values not only from the hippocampus but also from additional non-hippocampal brain regions that could be potentially relevant for group classification. Mean reference values and 95% confidence intervals were calculated for left and right hippocampi along with hippocampal asymmetry degree to test diagnostic accuracy. Results: Both methods showed excellent classification performance (AUC:> 0.914) with noticeable differences in absolute (cm3) and normalized volumes. Hippocampal asymmetry was the most accurate discriminator from all estimates (AUC:1~0.97). Similar results were achieved in the validation test with an automatic classifier (AUC:>0.960), disclosing hippocampal structures as the most relevant features for group differentiation among other brain regions. Conclusion: We calculated reference volumetry values from two commonly used methods to accurately identify patients with temporal epilepsy and hippocampal sclerosis. Validation with an automatic classifier confirmed the principal role of the hippocampus and its subregions for diagnosis.

Improvements on spatial coverage and focality of deep brain stimulation in pre-surgical epilepsy mapping.

Objective.Electrical stimulation mapping (ESM) of the brain using stereo-electroencephalography (SEEG) intracranial electrodes, also known as depth-ESM (DESM), is being used as part of the pre-surgical planning for brain surgery in drug-resistant epilepsy patients. Typically, DESM consists in applying the electrical stimulation using adjacent contacts of the SEEG electrodes and in recording the EEG responses to those stimuli, giving valuable information of critical brain regions to better delimit the region to resect. However, the spatial extension or coverage of the stimulated area is not well defined even though the precise electrode locations can be determined from computed tomography images.Approach.We first conduct electrical simulations of DESM for different shapes of commercial SEEG electrodes showing the stimulation extensions for different intensities of injected current. We then evaluate the performance of DESM in terms of spatial coverage and focality on two realistic head models of real patients undergoing pre-surgical evaluation. We propose a novel strategy for DESM that consist in applying the current using contacts of different SEEG electrodes (x-DESM), increasing the versatility of DESM without implanting more electrodes. We also present a clinical case where x-DESM replicated the full semiology of an epilepsy seizure using a very low-intensity current injection, when typical adjacent DESM only reproduced partial symptoms with much larger intensities. Finally, we show one example of DESM optimal stimulation to achieve maximum intensity, maximum focality or intermediate solution at a pre-defined target, and one example of temporal interference in DESM capable of increasing focality in brain regions not immediately touching the electrode contacts.Main results.It is possible to define novel current injection patterns using contacts of different electrodes (x-DESM) that might improve coverage and/or focality, depending on the characteristics of the candidate brain. If individual simulations are not possible, we provide the estimated radius of stimulation as a function of the injected current and SEEG electrode brand as a reference for the community.Significance.Our results show that subject-specific electrical stimulations are a valuable tool to use in the pre-surgical planning to visualize the extension of the stimulated regions. The methods we present here are also applicable to pre-surgical planning of tumor resections and deep brain stimulation treatments.

Quantitative characterization of extraocular orbital lesions in children using diffusion-weighted imaging.

BACKGROUND: Diffusion-weighted imaging (DWI) has been shown to be helpful in providing information about cellular density and also predicting the histological features of aggressive tumors. Several studies have evaluated this technique for orbital tumors. However, very few articles have focused exclusively on evaluating pediatric orbital masses and, within those, only a small number of patients were included in the study. OBJECTIVE: This study aimed to evaluate the use of DWI and apparent diffusion coefficient (ADC) values to differentiate between benign and malignant extraocular orbital lesions in children. MATERIALS AND METHODS: This retrospective study included 73 patients under the age of 18 seen in our hospital between October 2016 and February 2019. The extraocular orbital lesions were evaluated clinically and radiologically using DWI. The diagnosis was confirmed by either histological examination (after biopsy or surgery) or based on clinical and radiologic evaluation. RESULTS: The malignant lesions were found to have increased diffusion restriction in comparison to the benign lesions. The ADC values of the malignant lesions were significantly lower (P<0.0001). The use of a cutoff value of 0.99×10-3 mm2/s allowed for the differentiation of the benign lesions and malignant lesions with a sensitivity of 75% and a specificity of 100% while the cutoff point of 1.26×10-3 mm2/s had a sensitivity of 100% and a specificity of 73%. CONCLUSION: Measurement of ADC in extraocular orbital lesions in children may help differentiate malignant lesions from benign lesions.

Machine learning for filtering out false positive grey matter atrophies in single subject voxel based morphometry: A simulation based study.

Single subject VBM (SS-VBM), has been used as an alternative tool to standard VBM for single case studies. However, it has the disadvantage of producing an excessively large number of false positive detections. In this study we propose a machine learning technique widely used for automated data classification, namely Support Vector Machine (SVM), to refine the findings produced by SS-VBM. A controlled set of experiments was conducted to evaluate the proposed approach using three-dimensional T1 MRI scans from control subjects collected from the publicly available IXI dataset. The scans were artificially atrophied at different locations and with different sizes to mimic the behavior of neurological disorders. Results empirically demonstrated that the proposed method is able to significantly reduce the amount of false positive clusters (p < 0.05), with no statistical differences in the true positive findings (p > 0.05). This evidence was observed to be consistent for different atrophied areas and sizes of atrophies. This approach could be potentially be applied to alleviate the intensive manual analysis that radiologists and clinicians have to perform to filter out miss-detections of SS-VBM, increasing its usability for image reading.

Rasmussen syndrome: an atypical presentation in ten patients.

The aim of this study was to analyse the electroclinical and imaging findings and outcome of patients with Rasmussen syndrome (RS) with atypical manifestations. We conducted a retrospective, descriptive study of 10 of 44 consecutive patients with RS with atypical features, followed between 1999 and 2017. Six patients were boys and four were girls. The mean and median ages at onset of the seizures were 8.8 and 6.5 years, respectively (range: 4.6-13 years). All of the patients except one had seizures. Eight patients (80%) had epilepsia partialis continua that started at a mean age of 7.5 years (range: 7-15 years). In our series, hemiparesis without seizures was the first manifestation in three patients, one of whom had dual pathology. In two patients, the first manifestation was dyskinetic movements, followed by delayed-onset seizures associated with unilateral caudate atrophy. Two patients had a focal lesion mimicking focal cortical dysplasia as the first MRI abnormality; one of these two patients had epileptic spasms in clusters. Bilateral cerebral hemisphere involvement was observed in three patients during the course of the disease. Six of eight patients responded well to surgical treatment. Progressive hemiparesis alone or with delayed-onset seizures, dyskinetic movements associated with seizures, a focal lesion mimicking focal cortical dysplasia, and bilateral brain involvement were the atypical features recognized. Our series of patients responded well to surgery. Clinical, video-EEG, and neuroradiological follow-up is important for early confirmation of RS in order to initiate adequate management of the condition.

iElectrodes: A Comprehensive Open-Source Toolbox for Depth and Subdural Grid Electrode Localization.

The localization of intracranial electrodes is a fundamental step in the analysis of invasive electroencephalography (EEG) recordings in research and clinical practice. The conclusions reached from the analysis of these recordings rely on the accuracy of electrode localization in relationship to brain anatomy. However, currently available techniques for localizing electrodes from magnetic resonance (MR) and/or computerized tomography (CT) images are time consuming and/or limited to particular electrode types or shapes. Here we present iElectrodes, an open-source toolbox that provides robust and accurate semi-automatic localization of both subdural grids and depth electrodes. Using pre- and post-implantation images, the method takes 2-3 min to localize the coordinates in each electrode array and automatically number the electrodes. The proposed pre-processing pipeline allows one to work in a normalized space and to automatically obtain anatomical labels of the localized electrodes without neuroimaging experts. We validated the method with data from 22 patients implanted with a total of 1,242 electrodes. We show that localization distances were within 0.56 mm of those achieved by experienced manual evaluators. iElectrodes provided additional advantages in terms of robustness (even with severe perioperative cerebral distortions), speed (less than half the operator time compared to expert manual localization), simplicity, utility across multiple electrode types (surface and depth electrodes) and all brain regions.

Análisis video-electroencefalográfico de crisis epilépticas con inicio ictal de difícil lateralización, en epilepsia temporal mesial / Video-electroencephalographic analysis of epileptic seizures with ictal onset of difficult lateralization, in mesial temporal epilepsy

El propósito del trabajo fue analizar las características clínicas y electrofisiológicas de pacientes que presentaron crisis originadas en ambas regiones temporales en los registros de Video- EEG de scalp. Del total de la población con epilepsia temporal mesial (ET), resistente a las drogas, que ingresó a la Unidad de Video-EEG del Hospital Municipal Ramos Mejía y del Hospital de Alta Complejidad en Red El Cruce Dr. Néstor C. Kirchner, desde marzo de 2009 a marzo de 2014 (n=150), se seleccionaron 9 pacientes con crisis originadas en ambas regiones temporales (40 crisis focales con compromiso de la conciencia). Del total de los pacientes con epilepsia del lóbulo temporal fármaco-resistente, candidatos a cirugía de la epilepsia, en un 6% de los casos resultó difícil lateralizar la zona epileptógena con el registro de Video-EEG de scalp.

Congenital hemiparesis, unilateral polymicrogyria and epilepsy with or without status epilepticus during sleep: a study of 66 patients with long-term follow-up.

AIM: We retrospectively analysed the electroclinical features, treatment, and outcome in patients with unilateral polymicrogyria (PMG), focussing on epileptic syndrome with or without encephalopathy, with status epilepticus during sleep (ESES) or continuous spikes and waves during slow sleep (CSWS) syndrome. METHODS: From June 1990 to December 2012, 39 males and 27 females, aged 5-26 years, were studied. We did not include patients with bilateral PMG or cases with unilateral PMG associated with other cerebral lesions. The mean follow-up period was 12 years (range: 3-22 years). RESULTS: Mean age at epilepsy onset was 6.5 years. Focal motor seizures occurred in all cases and 25 had secondary generalised seizures. Six patients also had complex focal seizures. Interictal EEG recordings showed focal spikes in all cases. For 43 of 53 patients with epilepsy, aged 2-9.5 years, the electroclinical features changed. An increase in frequency of focal motor seizures was reported in 20 patients, negative myoclonus occurred in 32 patients, atypical absences in 25 patients, and positive myoclonus in 19 patients. All patients had a continuous symmetric or asymmetric pattern of spike-wave activity during slow-wave sleep. CONCLUSION: For patients presenting with congenital hemiparesis, negative or positive myoclonus, and absences and focal motor seizures with ESES/CSWS, unilateral PMG should be considered. Brain MRI is mandatory to confirm this cortical malformation. The most commonly used treatments were clobazam, ethosuximide, and sulthiame, alone or in combination. For refractory cases, high-dose steroids were administered and surgery was performed in two patients. Outcome was relatively benign.

Type II focal cortical dysplasia: electroclinical study and surgical outcome in 31 pediatric patients.

OBJECTIVE: The aim of this study was to analyze the electroclinical features and surgical outcome of 31 pediatric patients with focal cortical dysplasia (FCD) type II. MATERIAL AND METHODS: We conducted a retrospective, descriptive study of 31 patients with FCD type II followed between 1998 and 2011. We included patients with FCD type II confirmed by histopathological examination with abnormal magnetic resonance imaging and at least 1 year of follow-up. RESULTS: All patients had severe focal epilepsy; in infancy, four of them had also had epileptic spasms, associated with hypsarrhythmia in three. Focal status epilepticus occurred in five patients (16 %) and epilepsia partialis continua in one (3.2 %). Seizures occurred during sleep in 20 (64.5 %) and in clusters in 19 (61.3 %) patients. Neurological examination showed a mild motor deficit in seven (22.8 %) patients. Interictal abnormalities were characterized by rhythmic spikes and polyspike discharges, increasing during sleep in 13 (41.9 %) patients. Average time of follow-up after surgery was 4.7 years with a median time of 4 years and a range from 1 to 9 years. Engel classification class I was found in 20 (67.7 %) and class II in 3 cases (9.6 %). There were no significant changes after an average time of follow-up of 4.7 years. CONCLUSION: Our results confirm that surgery is the best treatment option for pediatric patients with refractory focal epilepsy due to type II FCD. A statistically significant correlation was found between a good prognosis and age at epilepsy onset older than 2 years.

Evaluación del haz espinotalámico mediante tractografía por resonancia magnética: nuevos aportes en la fisiopatología del dolor en pacientes con síndrome X / Spinothalamic Assessment by Magnetic Resonance Tractography: new Contributions in the Pathophysiology of Pain in Patients with Syndrome X

Introducción El síndrome X se asocia con signos y síntomas de isquemia, sin obstrucción significativa de las arterias coronarias. En los pacientes con este síndrome existe un aumento en la percepción de los estímulos cardíacos, aunque la causa de este trastorno se desconoce. Objetivo Explorar los tractos nerviosos sensitivos involucrados en la percepción anormal del dolor en mujeres que sufren de síndrome X. Material y métodos Estudio prospectivo que incluyó 24 mujeres: 12 con síndrome X, 6 con enfermedad coronaria documentada y 6 controles sanas. Se realizó el mapeo del tracto espinotalámico lateral mediante tractografía por difusión. Se analizaron las características anatómicas (líneas, vóxels, longitud) y físicas (anisotropía fraccional, coeficiente de difusión aparente, difusividad) de cada tracto. Resultados El haz espinotalámico lateral se pudo aislar en todas las pacientes evaluadas. No hubo diferencias en las características físicas de los tractos, pero existió una diferencia significativa en el número de vóxels de los tres grupos a expensas del grupo síndrome X (101,2 ± 46,9 vs. 83,2 ± 24 vs. 66 ± 16; p = 0,030), con una tendencia a presentar un número mayor de líneas en cada tracto. Conclusiones Se hallaron diferencias en las características anatómicas de los tractos de las pacientes con síndrome X respecto de los controles sanos y de las pacientes con enfermedad coronaria, con indemnidad en las características físicas de las fibras. Es probable que este estudio experimental sea el primero en demostrar que es posible evaluar in vivo los tractos neurológicos involucrados en la transmisión del dolor en este grupo de pacientes, lo cual abre un nuevo campo de investigación.(AU)

Background Syndrome X is associated with signs and symptoms of ischemia without significant coronary artery obstruction. There is an increased perception of cardiac stimuli in these patients, although the cause of this disorder is unknown. Objective The aim of this study was to analyze sensory nerve tracts involved in abnormal perception of pain in women with syndrome X. Methods This prospective study included 24 women: 12 with syndrome X; 6 with documented coronary heart disease, and 6 healthy controls. Lateral spinothalamic tract mapping by diffusion trac-tography was performed. The anatomic features (lines, voxels, and length) and physical features (fractional anisotropy, apparent diffusion coefficient, diffusivity) of each tract were analyzed. Results The lateral spinothalamic tract was isolated in all patients. No differences were found in the physical characteristics of the tracts, but there was a significant difference in the number of voxels of the syndrome X group when compared to the other two groups (101.2±46.9 vs. 83.2±24 vs. 66±16; p=0.030), with a tendency towards larger number of lines in each tract. Conclusions There were differences in the anatomic characteristics of tracts in syndrome X patients with respect to healthy controls and coronary artery disease patients, with indemnity in the physical characteristics of the fibers. This is probably the first experimental study to show that it is possible to evaluate "in vivo" neurological tracts involved in pain transmission in syndrome X patients, opening a new field of research.(AU)

Evaluación del haz espinotalámico mediante tractografía por resonancia magnética: nuevos aportes en la fisiopatología del dolor en pacientes con síndrome X / Spinothalamic Assessment by Magnetic Resonance Tractography: new Contributions in the Pathophysiology of Pain in Patients with Syndrome X

Introducción El síndrome X se asocia con signos y síntomas de isquemia, sin obstrucción significativa de las arterias coronarias. En los pacientes con este síndrome existe un aumento en la percepción de los estímulos cardíacos, aunque la causa de este trastorno se desconoce. Objetivo Explorar los tractos nerviosos sensitivos involucrados en la percepción anormal del dolor en mujeres que sufren de síndrome X. Material y métodos Estudio prospectivo que incluyó 24 mujeres: 12 con síndrome X, 6 con enfermedad coronaria documentada y 6 controles sanas. Se realizó el mapeo del tracto espinotalámico lateral mediante tractografía por difusión. Se analizaron las características anatómicas (líneas, vóxels, longitud) y físicas (anisotropía fraccional, coeficiente de difusión aparente, difusividad) de cada tracto. Resultados El haz espinotalámico lateral se pudo aislar en todas las pacientes evaluadas. No hubo diferencias en las características físicas de los tractos, pero existió una diferencia significativa en el número de vóxels de los tres grupos a expensas del grupo síndrome X (101,2 ± 46,9 vs. 83,2 ± 24 vs. 66 ± 16; p = 0,030), con una tendencia a presentar un número mayor de líneas en cada tracto. Conclusiones Se hallaron diferencias en las características anatómicas de los tractos de las pacientes con síndrome X respecto de los controles sanos y de las pacientes con enfermedad coronaria, con indemnidad en las características físicas de las fibras. Es probable que este estudio experimental sea el primero en demostrar que es posible evaluar in vivo los tractos neurológicos involucrados en la transmisión del dolor en este grupo de pacientes, lo cual abre un nuevo campo de investigación.

Background Syndrome X is associated with signs and symptoms of ischemia without significant coronary artery obstruction. There is an increased perception of cardiac stimuli in these patients, although the cause of this disorder is unknown. Objective The aim of this study was to analyze sensory nerve tracts involved in abnormal perception of pain in women with syndrome X. Methods This prospective study included 24 women: 12 with syndrome X; 6 with documented coronary heart disease, and 6 healthy controls. Lateral spinothalamic tract mapping by diffusion trac-tography was performed. The anatomic features (lines, voxels, and length) and physical features (fractional anisotropy, apparent diffusion coefficient, diffusivity) of each tract were analyzed. Results The lateral spinothalamic tract was isolated in all patients. No differences were found in the physical characteristics of the tracts, but there was a significant difference in the number of voxels of the syndrome X group when compared to the other two groups (101.2±46.9 vs. 83.2±24 vs. 66±16; p=0.030), with a tendency towards larger number of lines in each tract. Conclusions There were differences in the anatomic characteristics of tracts in syndrome X patients with respect to healthy controls and coronary artery disease patients, with indemnity in the physical characteristics of the fibers. This is probably the first experimental study to show that it is possible to evaluate "in vivo" neurological tracts involved in pain transmission in syndrome X patients, opening a new field of research.

Rapid and efficient localization of depth electrodes and cortical labeling using free and open source medical software in epilepsy surgery candidates.

Depth intracranial electrodes (IEs) placement is one of the most used procedures to identify the epileptogenic zone (EZ) in surgical treatment of drug resistant epilepsy patients, about 20-30% of this population. IEs localization is therefore a critical issue defining the EZ and its relation with eloquent functional areas. That information is then used to target the resective surgery and has great potential to affect outcome. We designed a methodological procedure intended to avoid the need for highly specialized medical resources and reduce time to identify the anatomical location of IEs, during the first instances of intracranial EEG recordings. This workflow is based on established open source software; 3D Slicer and Freesurfer that uses MRI and Post-implant CT fusion for the localization of IEs and its relation with automatic labeled surrounding cortex. To test this hypothesis we assessed the time elapsed between the surgical implantation process and the final anatomical localization of IEs by means of our proposed method compared against traditional visual analysis of raw post-implant imaging in two groups of patients. All IEs were identified in the first 24 H (6-24 H) of implantation using our method in 4 patients of the first group. For the control group; all IEs were identified by experts with an overall time range of 36 h to 3 days using traditional visual analysis. It included (7 patients), 3 patients implanted with IEs and the same 4 patients from the first group. Time to localization was restrained in this group by the specialized personnel and the image quality available. To validate our method; we trained two inexperienced operators to assess the position of IEs contacts on four patients (5 IEs) using the proposed method. We quantified the discrepancies between operators and we also assessed the efficiency of our method to define the EZ comparing the findings against the results of traditional analysis.

Noninvasive approach to focal cortical dysplasias: clinical, EEG, and neuroimaging features.

Purpose. The main purpose is to define more accurately the epileptogenic zone (EZ) with noninvasive methods in those patients with MRI diagnosis of focal cortical dysplasia (FCD) and epilepsy who are candidates of epilepsy surgery. Methods. Twenty patients were evaluated prospectively between 2007 and 2010 with comprehensive clinical evaluation, video-electroencephalography, diffusion tensor imaging (DTI), and high-resolution EEG to localize the equivalent current dipole (ECD). Key Findings. In 11 cases with white matter asymmetries in DTI the ECDs were located next to lesion on MRI with mean distance of 14.63 millimeters with topographical correlation with the EZ. Significance. We could establish a hypothesis of EZ based on Video-EEG, high-resolution EEG, ECD method, MRI, and DTI. These results are consistent with the hypothesis that the EZ in the FCD is complex and is often larger than visible lesion in MRI.