1/12. temporal lobe focal cortical dysplasia: MRI imaging using FLAIR shows lesions consistent with neoplasia.Focal cortical dysplasia (FCD), a form of neuronal migration disorder, is a malformative lesion of the neocortex that occurs during development of the brain. It can cause partial and generalized epilepsy. seizures occur at an early age and are often resistant to medication. Surgical resection has been found to be beneficial in these patients. Dual pathology, in the form of mesial temporal sclerosis, has been associated with FCD. At the Children's Hospital of Eastern ontario, four patients with temporal lobe FCD have recently, been identified. This paper discusses how these children presented and how they were managed, with particular emphasis on their MRI findings and differential diagnoses. In three of the four patients neuroimaging studies showed lesions consistent with a neoplastic process because of the large volume and mass effect. Radiologically, FCD may mimic the MRI appearance of tumors, such as dysembryoplastic neuroepithelial tumors, primitive neuroectodermal tumors, gangliogliomas, oligodendrogliomas, and astrocytomas. These lesions are best visualized on fluid-attenuated inversion recovery (FLAIR) imaging, a technique that has recently become applicable in the clinical setting, as we help demonstrate in this series. With better MRI capability, milder forms of FCD and microdysplasia may be distinguished.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
2/12. Focal cortical dysplasia of the temporal lobe with late-onset partial epilepsy: serial quantitative MRI.We describe serial studies of focal cortical dysplasia causing temporal lobe seizures and progressive aphasia in a 54-year-old woman. Initially, MRI volumetry of the temporal lobes showed significant left cortical thickening corresponding to an elevated amino-acid uptake in the left temporoparietal and inferior frontal cortex on SPECT using 3-[123I]iodo-alpha-methyl-L-tyrosine (IMT). After 1 year there was severe shrinkage of the left temporal lobe, possibly the result of recurrent complex partial seizures.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
3/12. Consistency of interictal and ictal onset localization using magnetoencephalography in patients with partial epilepsy.OBJECT: The aim of this study was to evaluate the spatial accuracy of interictal magnetoencephalography (MEG) in localizing the primary epileptogenic focus in comparison with alternative MEG-derived estimates such as ictal onset recording or sensory mapping of the periphery where seizures manifest. methods: During this retrospective study of 12 patients with epilepsy who had undergone successful magnetic source (MS) imaging with the aid of a dual 37-channel biomagnetometer as well as simultaneous MEG/electroencephalography (EEG) recordings, ictal events were observed in five patients and quantitative comparisons of interictal spike and ictal seizure onset source localizations were made. In the eight patients who had presented with sensorimotor seizure, source localization of cortical sites concordant with seizure foci was determined using somatosensory functional mapping, and the results were quantitatively compared with interictal spike source localizations. Interictal spike sources demonstrated on MEG localized to the same region as the corresponding ictal event or somatosensory source localizations. The mean distance between the ictal foci and interictal spike sources was 1.1 /- 0.3 cm. Results of functional somatosensory mapping in patients with sensorimotor seizures demonstrated that seizure sources consistently colocalized with interictal MEG spike sources, with a mean distance of 1.5 /- 0.4 cm. No systematic directional bias was observed. Interictal sources tended to be tightly clustered, and the mean ellipsoid volume, defined by one standard deviation of the source spatial coordinates, was 1 cm3. CONCLUSIONS: Interictal spike localizations on MEG were concordant with ictal and, where relevant, functional somatosensory mapping localizations. These findings support the interpretation of interictal spikes on MEG as a useful and effective noninvasive method for localizing primary seizure foci.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
4/12. Confirmation of nonconvulsive limbic status epilepticus with the sodium amytal test.Is it a seizure? This question can be difficult for a clinician to answer, and it may be more critical if the possible seizure lasts >30 min. Long-duration questionable seizure activity changes the question to, "Is it status epilepticus?" status epilepticus (SE) can be divided into convulsive and nonconvulsive types. Convulsive SE is the most easily recognized, whereas nonconvulsive SE is more clinically variable and controversial. The term nonconvulsive SE is more often applied to patients who are severely obtunded or comatose with minimal or no motor movements, or in a stupor of altered consciousness reflecting generalized ictal activity. Nonconvulsive SE also can be caused by focal seizure activity, sometimes restricted to deep small volumes of brain in which scalp EEG may not be diagnostic. We present the case of a patient who had dominant limbic hippocampal SE, but in whom the diagnosis could not be confirmed until a modified novel use of the sodium amytal test was performed.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
5/12. Palliative temporal resection for the treatment of intractable bioccipital epilepsy.RATIONALE: Temporal resection is usually ineffective in patients with occipital seizures. However, when seizures are unilateral occipital resections are now, occasionally, considered. When bilateral seizures and visual field defects exist, occipital resection can not be carried out. When predominantly lateralized, temporal seizure onset can be shown in such patients, palliative temporal resection may be justified. methods: We report two patients with medically refractory, bilateral occipital lobe seizures. Clinical and electrophysiological patterns suggested consistent spread of the ictal discharge to temporal lobe structures. Long-term EEG video monitoring was followed by stereoelectroencephalography (SEEG) to assess involvement of temporal and occipital regions symmetrically. RESULTS: Both patients had non-lateralized, elementary visual aura followed by loss of contact, automatisms, frequent falls and occasionally secondary generalization. brain MR imaging revealed bilateral parieto-occipital ischemic lesions without concomitant temporal volumetric abnormalities. They had bilateral or unilateral visual field defects. scalp EEGs showed bilateral temporal or temporo-parieto-occipital interictal and ictal epileptic abnormalities. Intracranial SEEG recordings confirmed the presence of multifocal, temporo-occipital epileptic abnormalities. In both however, disabling seizures originated in, or rapidly spread to the right hippocampus. Since occipital resections were inadvisable, both patients underwent selective, right amygdalohippocampectomy. seizures continued in both (two-year follow-up), but were much less severe, not associated with falling or secondary generalization, not followed by fatigue or headache and with faster recovery. CONCLUSION: When occipital resection is inadvisable because of bilateral or diffuse visual problems, palliative temporal resection may be considered in patients with lesional, bilateral occipital lobe epilepsy, and rapid seizure spread to mesial temporal structures. (Published with videosequences).- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
6/12. Neonatal schizencephaly: comparison of brain imaging.Schizencephaly is a regional disturbance of cerebral hemisphere formation occurring at 3-5 months gestation; neonatal presentation is uncommon. Three neonates with schizencephaly were evaluated with cranial ultrasonography (US), unenhanced computed tomography (CT), and magnetic resonance imaging (MRI) examinations. Common findings in US, CT, and MRI include parasylvian and midline clefts, size asymmetries of the basal ganglia and thalamus, cerebral parenchymal volume loss, ventriculomegaly, ventricular diverticula, and absence of the septum pellucidum. MRI and CT were superior to US in detecting calcification, gyral and sulcal abnormalities, and parasylvian clefts. MRI alone demonstrated homolateral absence of the sylvian vasculature, small medullary pyramids, low position of the fornix, and the thinning of the corpus callosum. Although US appears adequate as a screening test, MRI best defines the precise pathoanatomic findings of neonatal schizencephaly and allows for the prediction of neurologic outcomes in affected newborns.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
7/12. Emergency department management of children with acute isoniazid poisoning.We suggest that the following therapeutic regimen be followed in cases of isoniazid poisoning in children. In cases of intractable seizure activity in a child which remains unexplained, consider isoniazid poisoning. Give pyridoxine as an intravenous bolus to all children in whom isoniazid toxicity is suspected, who exhibit seizure activity and are known to have been exposed to isoniazid, or who have a history of ingesting one gram or more of isoniazid. It should be given on a gram-for-gram basis, and the clinician need not await serum isoniazid levels before administering pyridoxine. It can be safely given at a rate of five grams per three minutes in a 50 ml volume. In fact, serum isoniazid determinations are not available in many emergency departments and have not been shown to correlate closely with symptomatology. When available, serum isoniazid levels at best are subject to variability owing to sampling procedures (serum protein must be removed within two hours of sampling). The result is that serum isoniazid levels play only a minor role in the emergency department management of isoniazid poisoning. To potentiate the antidotal effects of pyridoxine, diazepam (0.1 mg/kg) may be given intravenously, preferably at a second intravenous site. Because the lactic acidosis seen after seizures resolves spontaneously, and because metabolic alkalosis may result following excess lactate loading, administration of bicarbonate is usually not necessary, and may be harmful in some cases. After pyridoxine treatment, syrup of ipecac may be given to empty the stomach.(ABSTRACT TRUNCATED AT 250 WORDS)- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
8/12. Dynamic changes of focal hypometabolism in relation to epileptic activity.The interictal hypometabolism in patients with focal epilepsy is usually regarded as stationary. In this study we investigated to which extent the hypometabolism may depend on the activity of the epileptic focus. In focal penicillin-induced epilepsy in rats the epileptic focus is hypermetabolic. This focus is accompanied by hypometabolism in widespread areas of adjacent cerebral cortex. The experiments revealed that these metabolic alterations are transient. Data from a patient experiencing a focal seizure during PET scanning gave similar results. They showed that the transition from interictal to ictal activity was accompanied by the development of hypermetabolic epileptic focus and the dynamic enlargement of the surrounding hypometabolism. Both, the experimental and clinical data provide evidence that the cerebral hypometabolism may vary in size depending on the activity of the epileptic focus. It is hypothesized that in human PET studies the large interictal hypometabolism may prevent the identification of hyperactive interictal epileptic foci due to the partial volume effects resulting from the limited spatial resolution of PET cameras.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
9/12. Focal cerebral magnetic resonance changes associated with partial status epilepticus.We report 2 patients with transient abnormalities on magnetic resonance imaging (MRI) associated with partial status epilepticus (SE). A man with a 4-month history of partial seizures had complex partial SE for 9 days, with left temporal maximum on ictal EEG. Left temporal lobe T2 signal was increased on MRI during SE, but cerebral MRI was normal 9 weeks later. A woman with "cryptogenic" temporal lobe epilepsy for 16 years had complex partial SE for 1 week, with right temporal maximum on ictal EEG. T2 Signal was increased over the entire right temporal lobe, extending into the insula, without mass effect, on MRI 1 month after SE ended. Repeat MRI 1 month later showed marked decrease in volume of increased T2 intensity, without gadolinium enhancement, but with mild mass effect over the right anterioinferomesial temporal areas. A gemistocytic astrocytoma was resected. Focal cerebral MRI abnormalities consistent with cerebral edema may be due to partial SE but also may indicate underlying glioma, even in long-standing partial epilepsy. Focal structural imaging changes consistent with neoplasm should be followed to full resolution after partial SE.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
10/12. Commentary: how has neuroimaging improved patient care?neuroimaging has significantly altered the management of patients with partial epilepsy. magnetic resonance imaging (MRI) has been demonstrated to be a reliable and accurate indicator of the common pathologic findings underlying a partial seizure disorder. Intracranial mass lesions have been shown to be highly coherent with the localization of the epileptogenic zone. An MRI-identified epileptogenic lesion affects the selection of patients for epilepsy surgery and alters the diagnostic evaluation and the operative strategy. The results of the MRI preoperatively have prognostic importance in patients undergoing surgical treatment for partial epilepsy. patients with lesional epileptic syndromes are considered favorable candidates for surgical ablative treatment. Hippocampal volume studies may predict the neurocognitive outcome in patients undergoing temporal lobe surgery. The use of MRI has resulted in a reduction in chronic intracranial EEG monitoring at most epilepsy centers, especially in patients with lesional pathology. MRI may be a reasonable initial "screening" procedure in selected patients with intractable partial epilepsy before consideration of a presurgical evaluation. A classification of partial epilepsy is proposed, based on the results of MRI, that may be useful for patients being considered for surgical treatment. Importantly, preoperative MRI must be correlated with the electrophysiologic studies and ictal semiology before decision-making regarding surgical therapy.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
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