Epilepsy is a chronic brain disease that is caused by various factors and characterized by recurrent, episodic and temporary central nervous system dysfunction. In the past few decades, despite the continuous development of antiepileptic drugs, there are still 20%-30% patients with epilepsy progressing to pharmacoresistant epilepsy (PRE), which leads to a significant increase in the morbidity and mortality of epilepsy. For those fraction of PRE, surgical treatment may be the only possible way to cure epilepsy. Accurate presurgical evaluation play an important role in making surgery decision and defining surgical extent and achieve better surgical outcome. Imaging, especially interictal fluorine-18-fluorodeoxyglucose-positron emission tomography (FDG-PET) is widely used in preoperative evaluation, which is of great significance in the detection of epileptogenic foci. Previous studies on FDG-PET have found that FDG-PET has a wide range of hypometabolism inpatients of PRE varying from different epileptic origins. Therefore, exploring the characteristics of glucose metabolism originating in different brain areas of resistant epilepsy can help to better interpret the results of FDG-PET and guide the preoperative localization of such patiens and better understand the potential mechanism of seizure propagation in PRE.

Inclusion Criteria: (a) Pharmacoresistant Epilepsy may be defined by International League Against Epilepsy (ILAE）as failure of adequate trials of two tolerated and appropriately chosen and used AED schedules (whether as monotherapies or in combination) to achieve sustained seizure freedom (judged by two epileptologists); (b) conventional MRI negative or nonspecific abnormalities; and (c) detailed information of long-term video-EEG, FDG-PET, high resolution MRI (HR-MRI) and neuropsychological assessment were acquired, (d) focal epilepsy defined by combining clinical, electrophysical and neuroimaging.

Exclusion Criteria: (a) generalized or multifocal epilepsy or the patient's electroclinical features were inconsistent with pharmacoresistant epilepsy; (b) idiopathic focal epilepsy; and (c) unsatisfactory imaging quality.

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We prospectively recruited 100 consecutive patients with pharmacoresistant epilepsy at our epilepsy center since Nov 2020. All the patients should have agreed to sign an informed consent.