| Research background:Epilepsy is a kind of central nervous system dysfunction syndrome,which is characterized by the imbalance of excitation and inhibition of neurons and the synchronous and abnormal discharge of neurons.In China,the prevalence of epilepsy patients is about 3.6~7 per thousand according to epidemiological statistics and the incidence rate of epilepsy is just below the stroke and becomes the second most common disease of central nervous system,in which temporal lobe epilepsy(TLE)accounts for about 60~70%.In most of the patients,drug therapy can be effective in controlling the symptoms,but there are also nearly 1/3 patients will develop into refractory epilepsy.Among them,the patients with medial temporal lobe sclerosis often belong to refractory epilepsy and the response to surgical treatment is better,so these patients need to be treated with surgery.For drug refractory epilepsy,better preoperative assessment is the foundation to ensure the operation effect,but is often difficult to accurately delineate epileptogenic lesions by the commonly used examination methods.At present,many kinds of functional molecular imaging may provide some additional information in the determination of the localization of the epileptic focus.Among them,PET brain imaging is a noninvasive technique for brain function and metabolism,which can provide the localization and quantitative information of epileptic focus,and has been widely used in clinical practice.In the past,the evaluation of PET brain imaging mainly depended on the visual evaluation and the calculation of the asymmetry index(AI).Although it has good effect for clinical diagnosis,the previous methods are influenced by the subjective judgment and the professional technical level of the diagnostic doctors,so that clinicians need a more objective and accurate analysis of the localization of epileptic foci.In the past,some researchers have studied the temporal lobe epilepsy using Statistical Parametric Mapping(SPM).However,because of the number of subjects and the control group are relatively less and comprehensive and comparative study of multiple methods is less,its diagnostic value is not exact and sure and therefore fail to enter the real clinical application.Objective: The purpose of this study was to study and develop the diagnosis of temporal lobe epilepsy by using SPM method.We compared and analyzed the diagnostic efficacy of different SPM methods with the postoperative pathology and follow-up results used as gold standard.The results of the SPM methods and visual analysis method,asymmetry index(AI analysis)were statistically analyzed and compared in order to evaluate the diagnostic efficacy of various methods.We select and establish a suitable SPM method and optimize the relevant parameters,so as to evaluate the value of SPM analysis method.In addition,we discussed the mechanism of temporal lobe epilepsy by comparison between patients and controls.The significance of this research is to establish appropriate and accurate statistical parametric mapping(SPM)method for the diagnosis of temporal lobe epilepsy based on voxel level,and the reasonable parameters that should be used in the analysis were obtained,the diagnostic value of SPM method in temporal lobe epilepsy was evaluated.Methods: A retrospective analysis was studied on 86 patients with refractory temporal lobe epilepsy(TLE)and 37 healthy volunteers.The analysis method includes three parts:(1)The visual analysis method,including the independent double blind visual measurement method and the visual AI analysis method.The SUVmean value of bilateral temporal lobe of all objects in study was recorded and the SUVmean value of bilateral temporal lobe in the patients and healthy controls was compared,the SUVmean value of the patient group was compared with that of the healthy control group.After that,the accuracy of the visual measurement method and the visual AI analysis method were compared.In addition,we use the SUVmean value of the two groups of research objects to carry out ROC curve analysis.(2)We used SPM analysis to study the lateralization of intractable temporal lobe epilepsy.Different confidence levels of P were used in two aspects of the study:(1)the data of each patient in patients group and healthy control group were tested with two samples t test based on voxel level.(2)The second analysis was designed to assess interhemispheric asymmetry in each patient by comparison with interhemispheric asymmetry existing among subjects of the control group.For this purpose,all scans were reversed in the sagittal plane to obtain mirror copies and were statistically analyzed and compared using One-way ANOVA test.(3)The diagnostic accuracy of several SPM methods under different confidence levels were analyzed.The two SPM analysis methods under the optimal confidence level were compared,then the optimization SPM diagnostic method and the visual analysis method were compared,and the diagnostic efficacy of the corresponding SPM diagnostic method was evaluated.The left temporal lobe epilepsy group,right temporal lobe epilepsy group and all epilepsy patients group was compared with the control group between groups respectively in order to evaluate the metabolic differences between the patients group and control group in different regions of the brain.Results:(1)We used the visual measurement method to accurately detect the epileptic foci in 70 patients,72 patients were diagnosed by the visual AI analysis method in the lateralization of intractable temporal lobe epilepsy,and there was no significant difference in diagnostic accuracy between the two groups.After statistical analysis,there was no significant difference in SUVmean between the two sides of the healthy control group.The SUVmean of the disease side in TLE group was lower than the corresponding value of the health side,there was a statistically significant difference.The SUVmean of the disease side in TLE group was lower than the corresponding value of the left and right temporal lobe in the healthy control group,the results were statistically significant.ROC curve analysis can be obtained by using SUVmean as the indicator of epileptic foci: When SUV value was 4.35,the sensitivity was 87.5%,the specificity was 81.4%,and the area under the curve was 0.844.(2)When individual patient and the control group were compared by SPM using the two sample t test under different confidence level P value,it was found that the diagnostic accuracy rate was 79.07%(68/86)when the confidence level was selected to be P<0.05(FWE correction value),which was better than other confidence level and roughly equivalent with the visual analysis method.When the individual patient's interhemispheric asymmetry was assessed in each patient by SPM under different confidence level P value,it was found that the diagnostic accuracy rate was 94.19%(81/86)when the confidence level was selected to be P<0.05(un corrected),which was better than other confidence level,the visual analysis method and the comparison method between individual patient and the control group analyzed by SPM using the two sample t test.(3)Group analysis found that other parts of the brain areas,besides the temporal lobe metabolism,also had decreased or increased metabolism.It can partly reflect the mechanism of temporal lobe epilepsy,and help clinicians to recognize the characteristics of the typical image of epilepsy.Conclusion: Overall,the SPM method is to analyze and compare all the voxels in the brain one by one to form a statistical parametric map,so the level of lesion detection can reach voxel level.SPM brain asymmetry analysis method is based on the statistical analysis of voxel taking into account part of the objective factors and ruled out the subjective factors of diagnostic physicians.This method can be used to find minute metabolic changes in different brain regions noninvasively,more objectively,scientifically and comprehensively.It has high detection rate in epileptic foci,and has high sensitivity,specificity and repeatability and clinical application value in the diagnosis of refractory TLE.Due to the characteristics of the program operation,it is expected to enter clinical practice. |
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