The Application Value Of Arterial Spin Labeling In The Localization Of Epileptogenic Focus

Background:Epilepsy is a chronic disease with the characteristics of sudden,short and recurrent attacks caused by a group of highly synchronized discharges of brain neurons.The incidence rate is second only to stroke in neurological diseases.Because of the difference of brain lesions and discharge sites,epileptic seizures can have a variety of clinical manifestations such as movement,sensation,consciousness,spirit,behavior,and autonomic nervous function abnormalities.Its high disability rate and long course of illness are the current social and public medical problems.At present,the diagnosis of epilepsy is mainly based on symptomology,dynamic video electroencephalogram,cranial magnetic resonance imaging,positron emission tomography,single photon emission computed tomography and so on.However,the spatial resolution of the ordinary electroencep-halogram is low,and it is difficult to detect the deep epileptic lesions.Cranial MRI can only detect patients with epilepsy caused by obvious morphological abnormalities.PET-CT and SPECT examinations are invasive examinations that require contrast agents,which are expensive and have low specificity for detecting epileptic lesions.Arterial spin labeling(ASL)is a magnetic resonance perfusing imaging method that uses freely diffusing water molecules as an internal tracer.It is non-invasive and repeatable,and can accurately assess cerebral blood flow(CBF)in patients with seizure and interictal period.ASL has been initially applied in the location of epileptogenic focus in patients with epilepsy.Methods:This study collected these informations about the gender,age,symptomology,past history,and cranial MRI examination(including the routine sequences and 3D ASL),epileptogenic focus located by cortical electrodes and postoperative pathological results of 25 patients who underwent epilepsy lesion resection from January 1,2019 to December 31,2020 in the Second Affiliated Hospital of Nanchang University.ASL is used to observe brain perfusion and metabolic changes in patients with epilepsy to locate epileptic lesions,and then compare it with the epileptogenic focus located by cortical electrodes to evaluate the application value of ASL in locating epileptogenic foci.At the same time,the detection rate of epileptic foci in DWI and ASL will be compared.Results:21 out of 25 patients with epilepsy had abnormal perfusion of ASL.The sites of abnormal perfusion in these 21 patients were confirmed as epileptic foci,or epileptogenic foci and their surrounding locations after intracranial electrode placement.Compared with the location of epileptogenic foci by ASL and intracranial electrodes,the results are completely or partially consistent,which reflects the application value of ASL for epileptogenic foci.The causes of epileptic foci were found after pathological examination,including focal cortical dysplasia(FCD),brain tumors,vascular malformations,cavernous hemangioma,and others.Among these 25 patients with epilepsy,15 cases showed no abnormalities on DWI,and 10 cases showed low signal changes.It was confirmed by intracranial electrodes that the low-signal area of DWI or its vicinity was epileptic foci,accounting for 40%(10/25);21 of the 25 patients had abnormal ASL,accounting for 84%(21/25),and 4 cases were normal.The results showed that ASL has a higher location and positive detection rate of epileptic foci than DWI.Conclusion:ASL has a certain application value in the location of epileptic lesions,but there is the possibility of expanding epileptic lesions;in detecting epileptogenic lesions,compared with DWI,the detection rate of ASL is higher.