Localization Of Epileptic Focus And Brain Functional Areas By Magnetic Source Imaging

The prevalence rate of epilepsy patients is about 3%-6% in China,20% patients are medically refractory epilepsy.Many children with medically refractory localization-related epilepsy had been treated by epilepsy surgery or gamma-knife radiotherapy. However,for epilepsy surgery to achieve seizure free with no neurologic deficit,precise localization of the epileptogenic zone and other important functional areas such as the anatomic localization of eloquent cortex is the key to get the good results. Individual variabilities in brain structure and the alterations by pathological mass often render inaccurate only by CT and MRI to identify the central sulcus. The traditional precise localization method is invasive intracranial electrtrodes. However, intracranial electrtrodes increase the operation time and probability of infection. Brath. and his colleagues localized the epileptic focus by magnetoencephalography(MEG)for the first time in 1982. They used a single-channel biomagnetometer and put forward the effect to localize the epileptic focus by MEG. Multiple-channel device increased the recording speed and promote the accuracy in localization in the last decade, and now There are 306-channels biomagnetometer to record the magnetic field at the same time. The merging of the technologies of Magnetoencephalography(MEG)and MRI(magnetic resonanceimaging,MRI) resulted in a new imaging method-MSI (magnetic source imaging, MSI).It is a non-invasive technique. There is no published paper on MEG in domestic. This paper is about several clinical application of MSI,that is : (1) Localization study of the epilepogenic cortex by magnetic source; (2) Functional localization of the human primary somatosensory cortice: a neuromagnetic study; ( 3 ) Localization of the primary somatosensory cortex in patients suffered from tumor within the skull bymagnetic source imaging; (4) Localization of the human primary auditory cortex by magnetic source imaging; (5) localization of the human language cortex by magnetic source imaging.The purpose of the study is to observe the precise localization to epileptic focus and define some important functional areas by MSI,such as somatosensory cortex,auditory cortex etc. We also aim to Instruct the clinical doctors make operation plan so as to resect the lesion in maximal range and keep the important functional areas and raise the patients quality of life after operation. The results obtained are as follows:1.Localization study of the epilepogenic cortex by magnetic source imagingObjective: To evaluate the value of MSI in localizing the epileptogenic cortex in epilepsy patients. Methods: 19 epilepsy patients were examined by 306- channel whole-scalp magnetoencephalography (MEG) made by 4D Neuroimaing company(U.S.A)and 1.5T MR unit made by GE(U.S.A), including 11 men and 8 women,aged 3 to 52 years(averaged 24 years old). The electrophysiological data obtained by the MEG can be superimposed on anatomic structural data obtained by MRI. Results: 15 patients were found the interictal spikes ,8 of 15 have multiple epileptogenic zone( two or more than two), 7 of 15 have one epileptogenic zone0 4 have no spikes. 3 of 15 show Hippocampal sclerosis in one hemisphere on MRI. MRI shows hippocampus atrophy in Hippocampal sclerosis patients. 2 of 15 show a cerebral malacia on MRI. The others are normal on MRI. MSI clearly defined the location of the epileptogenic zone.The epileptogenic zone localized in the same side in 1 of 3 patients with Hippocampal sclerosis, 1 of 3 shows epileptogenic zone localized in bilateral temporal lobe,l of 3 shows epileptogenic zone localized in the perisylvian region and perirolandic regions of the contralateral side. 2 cases have the sympotms of temporal epilepsy,MRI are normal,MSI shows the epileptogenic zone are located in the temporal lobe. These two cases only have one epileptogenic zone respectively. 1 has a local cerebral malacia in right frontal lobe, but theepileptic zones are far from the cerebral malacia focus. 1 has a local cerebral ma...