RESUMO
Implantable neural stimulators have been developed to aid patients with debilitating neurological conditions that are not amenable to other therapies. The aim of this article is to improve understanding of correct anatomical placement as well as the relevant imaging methods used to assess these devices. Potential complications following their insertion and an overview of the current indications and potential mechanism of action of these devices is provided.
Assuntos
Diagnóstico por Imagem/métodos , Terapia por Estimulação Elétrica/instrumentação , Complicações Pós-Operatórias/diagnóstico , Meios de Contraste , Humanos , Aumento da Imagem/métodos , Imageamento por Ressonância Magnética/métodos , Período Pós-Operatório , Tomografia Computadorizada por Raios X/métodosRESUMO
We have recently performed simultaneous intracranial EEG and fMRI recordings (icEEG-fMRI) in patients with epilepsy. In this technical note, we examine limited thermometric data for potential electrode heating during our protocol and found that heating was ≤0.1 °C in-vitro at least 10 fold less than in-vivo limits. We quantify EEG quality, which can be degraded by MRI scanner-induced artefacts, and fMRI image (gradient echo echo-planar imaging: GE-EPI) signal quality around the electrodes, which can be degraded by electrode interactions with B1 (radiofrequency) and B0 (static) magnetic fields. We recorded EEG outside and within the MRI scanner with and without scanning. EEG quality was largely preserved during scanning and in particular heartbeat-related artefacts were small compared to epileptic events. To assess the GE-EPI signal reduction around the electrodes, we compared image signal intensity along paths into the brain normal to its surface originating from the individual platinum-iridium electrode contacts. GE-EPI images were obtained at 1.5 T with an echo time (TE) of 40 ms and repetition time (TR) of 3000 ms and a slice thickness of 2.5 mm. We found that GE-EPI signal intensity reduction was confined to a 10 mm radius and that it was reduced on average by less than 50% at 5mm from the electrode contacts. The GE-EPI image signal reduction also varied with electrode orientation relative to the MRI scanner axes; in particular, cortical grid contacts with a normal along the scanner's main magnetic field (B(0)) axis have higher artefact levels relative to those with a normal perpendicular to the z-axis. This suggests that the artefacts were predominantly susceptibility-related rather than due to B1 interactions. This information can be used to guide interpretation of results of icEEG-fMRI experiments proximal to the electrodes, and to optimise artefact reduction strategies.
Assuntos
Artefatos , Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Eletrodos Implantados , Eletroencefalografia/métodos , Aumento da Imagem/métodos , Imageamento por Ressonância Magnética/métodos , Algoritmos , Mapeamento Encefálico/instrumentação , Eletroencefalografia/instrumentação , Humanos , Imageamento por Ressonância Magnética/instrumentação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Reino UnidoRESUMO
BACKGROUND: Epilepsy carries an increased risk of premature death. For some people with intractable focal epilepsy, surgery offers hope for a seizure-free life. The authors aimed to see whether epilepsy surgery influenced mortality in people with intractable epilepsy. METHODS: The authors audited survival status in two cohorts (those who had surgery and those who had presurgical assessment but did not have surgery). RESULTS: There were 40 known deaths in the non-surgical group (3365 person years of follow-up) and 19 in the surgical group (3905 person-years of follow-up). Non-operated patients were 2.4 times (95% CI 1.4 to 4.2) as likely to die as those who had surgery. They were 4.5 times (95% CI 1.9 to 10.9) as likely to die a probable epilepsy-related death. In the surgical group, those with ongoing seizures 1 year after surgery were 4.0 (95% CI 1.2 to 13.7) times as likely to die as those who were seizure-free or who had only simple partial seizures. Time-dependent Cox analysis showed that the yearly outcome group did not significantly affect mortality (HR 1.3, 95% CI 0.9 to 1.8). CONCLUSION: Successful epilepsy surgery was associated with a reduced risk of premature mortality, compared with those with refractory focal epilepsy who did not have surgical treatment. To some extent, the reduced mortality is likely to be conferred by inducing freedom from seizures. It is not certain whether better survival is attributable only to surgery, as treatment decisions were not randomised, and there may be inherent differences between the groups.
Assuntos
Epilepsias Parciais/mortalidade , Epilepsias Parciais/cirurgia , Adolescente , Adulto , Estudos de Coortes , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos , Análise de Regressão , Convulsões/epidemiologia , Análise de Sobrevida , Resultado do Tratamento , Adulto JovemRESUMO
Anterior temporal lobe resection is often complicated by superior quadrantic visual field deficits (VFDs). In some cases this can be severe enough to prohibit driving, even if a patient is free of seizures. These deficits are caused by damage to Meyer's loop of the optic radiation, which shows considerable heterogeneity in its anterior extent. This structure cannot be distinguished using clinical magnetic resonance imaging sequences. Diffusion tensor tractography is an advanced magnetic resonance imaging technique that enables the parcellation of white matter. Using seed voxels antero-lateral to the lateral geniculate nucleus, we applied this technique to 20 control subjects, and 21 postoperative patients. All patients had visual fields assessed with Goldmann perimetry at least three months after surgery. We measured the distance from the tip of Meyer's loop to the temporal pole and horn in all subjects. In addition, we measured the size of temporal lobe resection using postoperative T(1)-weighted images, and quantified VFDs. Nine patients suffered VFDs ranging from 22% to 87% of the contralateral superior quadrant. In patients, the range of distance from the tip of Meyer's loop to the temporal pole was 24-43 mm (mean 34 mm), and the range of distance from the tip of Meyer's loop to the temporal horn was -15 to +9 mm (mean 0 mm). In controls the range of distance from the tip of Meyer's loop to the temporal pole was 24-47 mm (mean 35 mm), and the range of distance from the tip of Meyer's loop to the temporal horn was -11 to +9 mm (mean 0 mm). Both quantitative and qualitative results were in accord with recent dissections of cadaveric brains, and analysis of postoperative VFDs and resection volumes. By applying a linear regression analysis we showed that both distance from the tip of Meyer's loop to the temporal pole and the size of resection were significant predictors of the postoperative VFDs. We conclude that there is considerable variation in the anterior extent of Meyer's loop. In view of this, diffusion tensor tractography of the optic radiation is a potentially useful method to assess an individual patient's risk of postoperative VFDs following anterior temporal lobe resection.
Assuntos
Lobectomia Temporal Anterior/efeitos adversos , Epilepsia do Lobo Temporal/cirurgia , Transtornos da Visão/etiologia , Campos Visuais , Vias Visuais/patologia , Adolescente , Adulto , Mapeamento Encefálico/métodos , Imagem de Difusão por Ressonância Magnética/métodos , Estudos de Viabilidade , Feminino , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Lobo Temporal/patologia , Transtornos da Visão/patologia , Vias Visuais/lesões , Adulto JovemRESUMO
Simultaneous EEG-fMRI acquisitions in patients with epilepsy often reveal distributed patterns of Blood Oxygen Level Dependant (BOLD) change correlated with epileptiform discharges. We investigated if electrical source imaging (ESI) performed on the interictal epileptiform discharges (IED) acquired during fMRI acquisition could be used to study the dynamics of the networks identified by the BOLD effect, thereby avoiding the limitations of combining results from separate recordings. Nine selected patients (13 IED types identified) with focal epilepsy underwent EEG-fMRI. Statistical analysis was performed using SPM5 to create BOLD maps. ESI was performed on the IED recorded during fMRI acquisition using a realistic head model (SMAC) and a distributed linear inverse solution (LAURA). ESI could not be performed in one case. In 10/12 remaining studies, ESI at IED onset (ESIo) was anatomically close to one BOLD cluster. Interestingly, ESIo was closest to the positive BOLD cluster with maximal statistical significance in only 4/12 cases and closest to negative BOLD responses in 4/12 cases. Very small BOLD clusters could also have clinical relevance in some cases. ESI at later time frame (ESIp) showed propagation to remote sources co-localised with other BOLD clusters in half of cases. In concordant cases, the distance between maxima of ESI and the closest EEG-fMRI cluster was less than 33 mm, in agreement with previous studies. We conclude that simultaneous ESI and EEG-fMRI analysis may be able to distinguish areas of BOLD response related to initiation of IED from propagation areas. This combination provides new opportunities for investigating epileptic networks.
Assuntos
Potenciais de Ação , Diagnóstico por Computador/métodos , Eletroencefalografia/métodos , Epilepsia/diagnóstico , Epilepsia/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Rede Nervosa/fisiopatologia , Adulto , Mapeamento Encefálico/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pediatria/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto JovemRESUMO
PURPOSE: To examine the cognitive risks of temporal lobe surgery in patients aged 50 years and older. METHODS: We analysed data from 55 patients who underwent temporal lobe surgery (26 left-sided:29 right sided) from 1988 to 2012 at our centre. Pre-surgical and one year post-operative memory and naming capacity were compared to data obtained from two younger cohorts; 185 aged 18-30 and 220 aged 31-49. RESULTS: Pre-operative memory impairments were most marked for the oldest cohort and were associated with a longer duration of epilepsy. Naming capacity improved with age and better performance was associated with a later age at epilepsy onset. Post-operative declines were largest in older patients, achieving statistical significance for verbal memory, naming and subjective ratings. Left temporal lobe resections carried the greatest risk of memory and naming decline. Cognitive outcomes were unrelated to seizure outcome, VIQ or mood. CONCLUSION: Our findings indicate the cognitive risks of TLE surgery are greater for older patients. Cognitive outcomes need to be considered when assessing the efficacy of epilepsy surgery in older cohorts and pre-operative performance levels need to be taken into account.
Assuntos
Cognição , Epilepsia do Lobo Temporal/psicologia , Epilepsia do Lobo Temporal/cirurgia , Memória , Procedimentos Neurocirúrgicos/efeitos adversos , Adolescente , Adulto , Fatores Etários , Idoso , Estudos de Coortes , Epilepsia do Lobo Temporal/fisiopatologia , Feminino , Humanos , Masculino , Transtornos da Memória/fisiopatologia , Pessoa de Meia-Idade , Testes Psicológicos , Risco , Fatores de Risco , Percepção da Fala , Resultado do Tratamento , Adulto JovemRESUMO
Spinal intramedullary metastases present with rapidly progressing neurological deficits and have an extremely poor prognosis. Prompt investigation and management are required. This case history illustrates that radiotherapy and steroids can be effective in returning motor function. The behaviour of the primary tumour and the stage of the disease influence whether surgery is appropriate.
Assuntos
Neoplasias Brônquicas/patologia , Neoplasias da Medula Espinal/radioterapia , Neoplasias da Medula Espinal/secundário , Terapia Combinada , Evolução Fatal , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias da Medula Espinal/tratamento farmacológico , Esteroides/uso terapêuticoRESUMO
A rare case of a giant, temporo-occipital sinus pericranii is presented. A 38-year-old male presented with minor symptoms of headache and heaviness over an enlarging temporo-occipital bone defect. Within the defect a soft, compressible, mass lesion was observed, which varied in size with changes in intracranial pressure. Radiological imaging demonstrated bone erosion around a fluid filled mass, which on angiography communicated via a series of channels with the transverse sinus. A diagnosis of sinus pericranii was made. Due to the risk of future complication the patient elected to undergo surgery, which successfully resected the mass and obliterated the venous communications with the diploic veins and transverse sinus. The classification, aetiology, differential diagnosis, radiological characteristics and management options relating to sinus pericranii are discussed.
Assuntos
Cavidades Cranianas/patologia , Seio Pericrânio/patologia , Crânio/patologia , Adulto , Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Cavidades Cranianas/diagnóstico por imagem , Cavidades Cranianas/cirurgia , Diagnóstico Diferencial , Humanos , Complicações Intraoperatórias/etiologia , Complicações Intraoperatórias/cirurgia , Imageamento por Ressonância Magnética , Masculino , Seio Pericrânio/diagnóstico por imagem , Seio Pericrânio/cirurgia , Crânio/irrigação sanguínea , Crânio/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Resultado do TratamentoRESUMO
We report the case of a chronic subdural haematoma caused by repetitive heading of a football which led to the diagnosis of a middle fossa arachnoid cyst. The association between arachnoid cysts and subdural haematoma is discussed as are safety implications in sporting injuries.
Assuntos
Cistos Aracnóideos/complicações , Traumatismos Craniocerebrais/complicações , Hematoma Subdural Crônico/complicações , Futebol/lesões , Adulto , Cistos Aracnóideos/cirurgia , Cefaleia/etiologia , Hematoma Subdural Crônico/cirurgia , Humanos , Náusea/etiologia , Fatores de Risco , Tomografia Computadorizada por Raios X/métodos , Resultado do Tratamento , Vômito/etiologiaAssuntos
Hemorragia Cerebral/induzido quimicamente , Transtornos Relacionados ao Uso de Substâncias/complicações , Adulto , Transtornos Relacionados ao Uso de Anfetaminas/complicações , Transtornos Relacionados ao Uso de Cocaína/complicações , Humanos , Masculino , Doenças do Sistema Nervoso/induzido quimicamente , PrognósticoRESUMO
Granule cell dispersion (GCD) is a common finding in hippocampal sclerosis in patients with intractable focal epilepsy. It is considered to be an acquired, post-developmental rather than a pre-existing abnormality, involving dispersion of either mature or newborn neurones, but the precise factors regulating it and its relationship to seizures are unknown. We present two cases of GCD with associated CD34-immunopositive balloon cells, a cell phenotype associated with focal cortical dysplasia type IIB, considered to be a developmental cortical lesion promoting epilepsy. This observation opens up the debate regarding the origin of balloon cells and CD34 expression and their temporal relationship to seizures.
Assuntos
Giro Denteado/patologia , Neurônios/classificação , Neurônios/patologia , Adulto , Antígenos CD34/metabolismo , Epilepsias Parciais/complicações , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Humanos , Neurônios/metabolismo , Esclerose/etiologiaRESUMO
Newer MRI methods can detect cerebral abnormalities not identified on routine imaging in patients with focal epilepsy. Correlation of MRI with histopathology is necessary to understand the basis of MRI abnormalities and subsequently predict histopathology from in vivo MRI. The aim of this study was to determine if particular quantitative MR parameters were associated with particular histological features. Nine patients with temporal lobe epilepsy were imaged at 1.5 T using standard presurgical volumetric and quantifiable sequences: magnetization transfer and FFT2. The resected temporal lobe was registered with the volumetric MRI data according to our previously described method to permit correlation of the modalities. Stereologically measured neuronal densities and field fraction of GFAP, MAP2, synaptophysin and NeuN immunohistochemistry were obtained. Analyses were performed in the middle temporal gyrus and compared with quantitative MRI data from the equivalent regions. There was a significant Spearman Rho negative correlation between NeuN field fraction and the T2 value in gray matter (correlation coefficient -0.72, p=0.028). There were no significant correlations between any neuropathological and MR measures in white matter. These preliminary findings suggest that T2 in gray matter is sensitive to the proportion of neuronal tissue. Novel quantitative MRI measures acquired with higher field strength magnets, and so with superior signal to noise ratios, may generate data that correlate with histopathological measures. This will enable better identification and delineation of the structural causes of refractory focal epilepsy, and will be of particular benefit in patients in whom current optimal MRI does not identify a relevant abnormality.
Assuntos
Encefalopatias/diagnóstico , Epilepsia do Lobo Temporal/diagnóstico , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Psicocirurgia , Lobo Temporal/cirurgia , Adulto , Axônios/patologia , Encefalopatias/patologia , Encefalopatias/cirurgia , Dendritos/patologia , Dominância Cerebral/fisiologia , Epilepsia do Lobo Temporal/patologia , Epilepsia do Lobo Temporal/cirurgia , Feminino , Proteína Glial Fibrilar Ácida/análise , Hipocampo/patologia , Hipocampo/cirurgia , Humanos , Masculino , Proteínas Associadas aos Microtúbulos/análise , Pessoa de Meia-Idade , Neurônios/patologia , Sensibilidade e Especificidade , Software , Estatística como Assunto , Sinaptofisina/análise , Lobo Temporal/patologiaRESUMO
Anthropometric data (triceps skinfold thickness, mid-arm circumference and arm muscle circumference) have been obtained from 114 normal elderly individuals and are presented as a suitable reference range for use in nutritional assessment of the elderly. In males the results did not differ significantly from existing standards for younger men but in females there was a significant difference from similar standards for younger women. These findings suggest that there is an increase in fat and a decrease in lean body mass with advancing age in females but not in males. This difference is discussed.
Assuntos
Idoso , Antropometria , Feminino , Humanos , Masculino , Fenômenos Fisiológicos da Nutrição , Dobras CutâneasRESUMO
Stereotactic radiosurgery has been proposed as the first line treatment for acoustic tumours and has been particularly advocated in cases of Type 2 Neurofibromatosis (NF2) with bilateral acoustic nerve tumours. We present the case of a 22-year-old male with NF2 and bilateral acoustic nerve tumours. He underwent an uncomplicated excision of the larger, left sided lesion. Histology showed a benign acoustic schwannoma with no atypical features. One year later he underwent stereotactic radiosurgery (Gamma Knife 1500 cGy) to the right sided lesion. After initial swelling, within 12 months the tumour had reduced in size and undergone central necrosis. However, 2 years later MRI of the brain revealed a dramatic increase in the size of the right sided tumour, with considerable brain stem compression. The patient subsequently died. This highly unusual case highlights the need for careful clinical and radiological follow up. in patients with acoustic tumours, regardless of the treatment method employed.
Assuntos
Recidiva Local de Neoplasia , Neuroma Acústico/patologia , Neuroma Acústico/cirurgia , Radiocirurgia , Adulto , Progressão da Doença , Evolução Fatal , Humanos , Imageamento por Ressonância Magnética , Masculino , Neurofibromatose 2/complicaçõesRESUMO
The epidemic of abuse of the so-called 'designer drugs' amphetamine, cocaine and ecstasy--is fast replacing traditional aetiological factors as the largest cause of intracerebral haemorrhage among young adults. Traditional teaching is that these represent hypertensive haemorrhages. Recent reports, however, have indicated that these patients may harbour underlying vascular malformations. We review 13 patients with a positive history of drug abuse preceding the onset of intracerebral haemorrhage. These patients presented to the National Hospital for Neurology and Neurosurgery in central London over a 7-month period. Of the 13 patients (eight male, five female), average age 31 years (19-43) years), 10 were well enough to undergo cerebral angiography. Intracranial aneurysms were demonstrated in six patients and arteriovenous malformations in three patients. In only one of the patients was the angiogram normal. A further patient was subsequently shown to have a middle cerebral artery aneurysm at autopsy. The epidemiology, pharmacology and systemic effects of these drugs are considered. The mechanisms by which these compounds cause intracerebral complications and their influence on prognosis are discussed. The incidence of intracerebral haemorrhage (ICH), ischaemic cerebral infarctions and subarachnoid haemorrhage (SAH) following drug abuse is increasing. Contrary to historical opinion, drug-related ICH is frequently related to an underlying vascular malformation. Arteriography should be part of the evaluation of most young patients with nontraumatic ICH. A thorough history focusing on the use of illicit substances and toxicological screening of urine and serum should be part of the evaluation of any young patient with a stroke.
Assuntos
Malformações Arteriovenosas/complicações , Hemorragia Cerebral/etiologia , Aneurisma Intracraniano/complicações , Transtornos Relacionados ao Uso de Substâncias/complicações , Adulto , Transtornos Relacionados ao Uso de Anfetaminas/complicações , Transtornos Relacionados ao Uso de Anfetaminas/epidemiologia , Malformações Arteriovenosas/diagnóstico , Angiografia Cerebral , Hemorragia Cerebral/induzido quimicamente , Hemorragia Cerebral/epidemiologia , Transtornos Relacionados ao Uso de Cocaína/complicações , Transtornos Relacionados ao Uso de Cocaína/epidemiologia , Feminino , Humanos , Aneurisma Intracraniano/diagnóstico , Masculino , N-Metil-3,4-Metilenodioxianfetamina , PrognósticoRESUMO
Metastatic lesions in the suprasellar region are extremely rare. The differential diagnosis of a focal lesion at this site is wide ranging and lesions often have a similar radiological appearance. We present a woman with known Wegener's granulomatosis who lost vision while on medical treatment for a presumed granuloma at this site. Exploration revealed a metastatic carcinoma of unknown origin. Attention is drawn to the importance of making a histological diagnosis in cases of suprasellar lesions.
Assuntos
Adenocarcinoma/secundário , Neoplasias Encefálicas/secundário , Granulomatose com Poliangiite/diagnóstico , Hemianopsia/etiologia , Neoplasias Primárias Desconhecidas/diagnóstico , Neoplasias Hipofisárias/secundário , Adenocarcinoma/diagnóstico , Adenocarcinoma/cirurgia , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/cirurgia , Diagnóstico Diferencial , Feminino , Granulomatose com Poliangiite/cirurgia , Hemianopsia/cirurgia , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Neoplasias Primárias Desconhecidas/cirurgia , Neoplasias Hipofisárias/diagnóstico , Neoplasias Hipofisárias/cirurgiaRESUMO
Spinal haemangioblastomas are rare, accounting for only about 7% of all central nervous system cases. The case of a 40-year-old woman with a haemangioblastoma arising solely from a cervical sensory nerve root is presented. At operation via a cervical laminectomy, it was possible to resect the tumour en masse with the sensory ramus, by extending the laminectomy through the exit foramen for C6. Haemangioblastomas are commonly intramedullary, and have only been reported in this location on one previous occasion. The patient has Von Hippel-Lindau syndrome and a history of multiple solid tumours. The possible role of the Von Hippel-Lindau tumour suppressor gene in the pathogenesis of these neoplasms is discussed.
Assuntos
Hemangioblastoma/etiologia , Neoplasias do Sistema Nervoso Periférico/etiologia , Raízes Nervosas Espinhais , Doença de von Hippel-Lindau/complicações , Adulto , Feminino , Hemangioblastoma/cirurgia , Humanos , Pescoço , Neoplasias do Sistema Nervoso Periférico/cirurgiaRESUMO
Deep-seated skull base tumours provide as much a challenge to the surgeons' skills of localisation as to his technical abilities during the resection. These lesions are frequently inaccessible and lie adjacent to vital structures requiring extensive cerebral retraction for adequate exposure and direct visualisation. The ISG viewing wand is a newly developed image guidance system to aid direction of the operative approach and localisation of intracerebral pathology. We discuss its use in the management of a trigeminal neuroma.
Assuntos
Neoplasias dos Nervos Cranianos/cirurgia , Neuroma/cirurgia , Técnicas Estereotáxicas/instrumentação , Nervo Trigêmeo , Neoplasias dos Nervos Cranianos/patologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neuroma/patologia , Tomografia Computadorizada por Raios XRESUMO
In 37 elderly subjects undergoing measurement of whole body retention of 58Co-B12 at 7 and/or 14 days it was observed that significant (greater than 5%) retention of an inert non-absorbable marker (51CrCl3) occurred at 7 days in 23% of subjects and at 14 days in 8% of subjects. In view of the substantial retention of marker at 7 days it is suggested, therefore, that 14-day measurements of B12 retention are more appropriate than 7-day measurements in the elderly. Whole body retention of vitamin B12 at 14 days was measured in 51 healthy elderly subjects. Results obtained did not correlate with age, between 60 and 96 years, and were no different from results obtained from younger subjects in previously reported studies. It is concluded that vitamin B12 absorption, per se, does not decline with age.