Intracranial electrographic recording, especially stereoencephalography (SEEG), remains the gold standard for preoperative localization in epilepsy patients. However, this method is invasive and has low spatial resolution. In 1982, magnetoencephalography (MEG) began to be used in epilepsy clinics. MEG is not affected by the skull and scalp, can provide signals with high temporal and spatial resolution, and can be used to determine the epiletogensis zone (EZ) and the seizure onset zone (SOZ). Magnetic source imaging (MSI) is a method that superimposes the MEG data on a magnetic resonance image (MRI) and has become a major tool for presurgical localization. The applicability of MEG data has been largely improved by the development of many post-MRI processing methods in the last 20 years. In terms of the sensitivity of localization, MEG is superior to VEEG, MRI, PET and SPECT, despite inferiority to SEEG. MEG can also assist in the intracranial placement of electrodes and improve preoperative planning. Limitations of MEG include high cost, insensitivity to radiation source, and difficulty in locating deep EZ in the medial regions of the brain. These limitations could be overcome by new generations of equipment and improvement of algorithmics.
Drug-resistant epilepsy (DRE) not only have disruption of the patients by seizure, but also influence the quality of life, cognitive function and social association, as well as development delay even retrogression for children. Epilepsy surgery is the only curative treatment currently available for focal lesional pharmacoresistant epilepsy, five years complete seizure freedom rates was around 60% after surgery. The criterion of surgical intervention at present is achievement for the diagnosis of DRE, thereafter consideration of early epilepsy surgery, but these maybe a long-term duration. Recent advance in examine methods and surgical techniques have improved the surgical treatment of epilepsy, to such patient with focal lesional structure abnormality, before the DRE emergence, under the discussion of the multidisciplinary team. Children under 3 years old, the brain have greater neural plasticity, early surgical treatment is expected at allow the healthy brain to recover and develop the language function and quality of life. Numerous cause may pose abstracts to the delay of surgical intervention: (1) diagnosis delay; (2) patient himself and their familiar recognize that there have same risk of surgical treatment; (3) the primary doctor firmly believe that epilepsy surgery is the ultimate methods; (4) special problems of the patient, such including: age, comorbidity, and the location of symptom, EEG as well as imaging non-conformation.
Currently, about one-third of patients with anti-epilepsy drug or resective surgery continue to have sezure, the mechanism remin unknown. Up to date, the main target for presurgical evaluation is to determene the EZ and SOZ. Since the early nineties of the last century network theory was introduct into neurology, provide new insights into understanding the onset, propagation and termination. Focal seizure can impact the function of whole brain, but the abnormal pattern is differet to generalized seizure. Brain network is a conception of mathematics. According to the epilepsy, network node and hub are related to the treatment. Graphy theory and connectivity are main algorithms. Understanding the mechanism of epilepsy deeply, since study the theory of epilepsy network, can improve the planning of surgery, resection epileptogenesis zone, seizure onset zone and abnormal node of hub simultaneously, increase the effect of resectiv surgery and predict the surgery outcome. Eventually, develop new drugs for correct the abnormal network and increase the effect. Nowadays, there are many algorithms for the brain network. Cooperative study by the clinicans and biophysicists instituted standard and extensively applied algorithms is the precondition of widely used clinically.