Functional Neuroimaging of Epilepsy

  • Noriko Salamon


Epilepsy is a chronic progressive neurological disorder that affects 1% of the world population with an incidence of 70 per 100,000 per year [1]. About 30% of the patients have drug-resistant epilepsy [2]. Recent technical advances in neuroimaging have made many previously undetectable lesions visible, and magnetic resonance imaging (MRI) has become the primary imaging modality in the epilepsy workup. Many patients with temporal lobe epilepsy due to hippocampal sclerosis or cortical dysplasia have had temporal lobe resection and gained successful seizure control [3]. With modern neuroimaging, the surgical indications have expanded, and surgery is now one of the important treatment options in both adult and pediatric intractable epilepsy. It is known that seizure control is improved when the preoperative imaging demonstrates the border of the lesion [4]. Epilepsy surgery includes temporal lobectomy, extratemporal lesionectomy, hemispherectomy, corpus callosotomy, and subpial transections. The etiologies of surgically treatable epilepsy include hippocampal sclerosis, focal cortical dysplasia (FCD), tuberous sclerosis, neoplasm, perinatal stroke, vascular malformations, and much rarer diseases such as Rasmussen encephalitis and hemimegalencephaly. The role of the neuroradiologist for presurgical evaluation is not only to demonstrate a structural abnormality using multimodality techniques but also to ­provide anatomical information about the lesion in order to obtain improved postsurgical outcomes without causing unnecessary neurological deficits. As epilepsy is a functional disease, the lesion found in MRI is not always equivalent to the epileptogenic region. The neuroradiologist must work as a member of a team with neurologists and neurosurgeons to understand the clinical and electrophysiological assessments an to interpret the ­functional neuroimaging. Co-registration of the MRI, ­positron emission tomography (PET), single photon emission computed tomography (SPECT), functional MRI (fMRI), and magnetoencephalography (MEG) are fundamental to the presurgical evaluation. This multidisciplinary and multimodality approach is the key to the successful postsurgical outcomes. In this chapter, different techniques to explore intractable epilepsy are discussed, including fluorodeoxyglucose (FDG) PET, MEG, and diffusion tensor imaging­ (DTI) in combination with structural MRI.


Diffusion Tensor Imaging Tuberous Sclerosis Complex Epilepsy Surgery Hippocampal Sclerosis Focal Cortical Dysplasia 
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Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  1. 1.Department of RadiologyUCLA Medical CenterLos AngelesUSA

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