The role of magnetoencephalography in “nonlesional” epilepsy

• Published in: Epilepsia (Copenhagen) Vol. 52; no. s4; pp. 10 - 14
• Main Authors: Funke, Michael E., Moore, Kevin, Orrison Jr, William W., Lewine, Jeffrey David
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-07-2011; Wiley-Blackwell
• Subjects: Adolescent; Adult; Anticonvulsants. Antiepileptics. Antiparkinson agents; Biological and medical sciences; Brain - pathology; Brain - physiopathology; Brain imaging; Child; Child, Preschool; Electroencephalography; Epilepsy - diagnosis; Epilepsy - pathology; Epilepsy - physiopathology; Female; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Humans; Magnetoencephalography; Male; Medical sciences; Middle Aged; MRI; Neocortical epilepsy; Nervous system (semeiology, syndromes); Neurology; Neuropharmacology; Pharmacology. Drug treatments; Seizures - diagnosis; Seizures - pathology; Seizures - physiopathology; Young Adult; Nervous system diseases; Brain imaging; Magnetoencephalography; MRI; Epilepsy; Central nervous system disease; Central nervous system; Neocortical epilepsy; Nuclear magnetic resonance imaging; Cerebral disorder; Encephalon
• ISSN: 0013-9580; 1528-1167
• DOI: 10.1111/j.1528-1167.2011.03144.x

Summary
The surgical management of neocortical epilepsy is challenging because many patients are without obvious structural lesions, or lesions are small and easily overlooked during routine clinical interpretation of magnetic resonance imaging (MRI) data. Even when functional imaging data suggest focal epileptiform pathology, in the absence of a concordant structural lesion, invasive monitoring is often required to confirm that an appropriate surgical target has been identified. This study sought to determine the extent to which knowledge of magnetoencephalography (MEG) data can augment the MRI‐based detection of structural brain lesions. MRI and whole‐head MEG data were obtained from 40 patients with neocortical epilepsy. As a result of MEG data, 29 cases were sent for MRI reevaluation. In seven of these cases, MEG‐guided review led to specification of now clear, but previously unidentified, lesions. There were two additional cases for which follow‐up high‐resolution imaging did not confirm structural abnormalities. In patients with neocortical epilepsy, MEG is a useful adjunct to MRI for the identification of structural lesions.