The Study Of The Value And Influencing Factors Of Magnetoencephalography (MEG) In Presurgical Evaluation Of Patients With Refractory Temporal Epilepsy

Background and Objective: Srugery is a utilitical treatment for localized refractory epilepsy. With the development of the technique to localize epileptogenic zone in recent years, the remission rate of epilepsy especially temporal epilepsy (TLE) seemed gradually rising up. So, presurgical evaluation is important in clinical work. The use of kinds of electraphysiological and morphology technique in presurgical evaluation is hot spot. As a new technique of biomagnetism, MEG is the most sensitive and noninvasive encephalo-technique. This paper is to evaluate deeply the localizing value and influence factor of MEG in pre－surgical evaluation and compare the difference between MEG and VEEG, and try to find the relation between MEG and MRI. Methods: Choosing 47 patients identified with refractory temporal lobe epilepsy. All patients had examinations including MEG,Video-EEG and Magnetic Resonance Imaging to localizing epitogenic area firstly, and taking Electrocorticography as golden standard, Comparing to the spike discovering rate of MEG and VEEG in three temporal epilepsy tipes. Using statistic X2 or Fisher method to comparing the results of localization between MEG and VEEG and using Logistic analysis to try to find influencing factors of the localization of MEG. Analysising the correlating coefficient of localizing accuracy of MEG and the volume of hippocampus and comparing the diagnostic difference of Hippocampus sclerosis (HS) between reading imaging sheet by eyes and by measuring.Results: All 47 cases had surgical operation according the results of MEG,VEEG,MRI and ECoG finally .47 cases includes 32 male and 15 female, with age from 6 to 54 years (mean 23±10) and the treatment process from 2 to 23 years (mean 7± 5.89), 82.14% of patients have good prognosis in a short period of following after surgery.28 cases with following 3～12 months and 23(82.14%) cases seizure free or rare.In 47 patients, 42 cases (89.36%) find spike dipoles in MEG, 35 cases (74.47%) fit or partly fit to ECoG. The spikes discovering rate and the degree of localizing accuracy is different in three temporal epilepsy tipes: it is highest in 7 cases (100%) with neocortical temporal lobe epilepsy (NTLE), the localizing results of MEG in 5 cases (71.43%) wholly fit to ECoG and 2 cases (28.75%)partly fit to ECoG. Compound TLE follows, 32(96.97%)cases were discovered the spikes dipole and 11 cases wholly fit to ECoG and 14 cases (42,42%)partly fit to ECoG. It is lowest in mesiotemporal lobe epilepsy (MTLE), 3 cases (42.86%) were discoveried spike dipole. 3 cases (42.86%)wholly fit to ECoG .The difference between them has statistic significance. The ictal frequency is a obvious influencing factor for the localization of MEG in Logistic statistic analysis.In 47 patients, 46 cases find spike dipoles in VEEG, the spike discovering rate is 97.87%; 18(85.11%) cases wholly fit or partly fit to ECoG. It seems no obvious difference between VEEG and MEG about the spike discovering rate and the degree of localizing accuracy. The spikes discovering rate and the degree of localizing accuracy in is different in three temporal epilepsy tipes: It is higher by MEG than VEEG in NTLE (71.43% wholly fit to EcoG and 28.57% partly fit to ECoG) and with statistic significance. It is lower by MEG in MTLE and compound TLE without statistic significance.In 6 cases with structural lesion, 5 cases (83.33%) find spike dipoles by MEG and were identified by ECoG; In 11 cases with normal MRI, 9 cases(81.28%) find spike dipoles; The correlating coefficient is 0.1158 (P>0.05); The diagnosis rate of HS is 68.09% by measuring hippocampus facture (HF) MRI and 55.32% by reading MRI by eyes. Conclusions: In TLE, MEG could reliably identify a temporal lobe source and have important clinical value; Spikes discovering rate and the degree of localizing accuracy is different in different epileptogenic zone from TLE. The depth of epileptogenic zone is an important influencing factor for MEG, it is easily found in superfac...