¹⁸F-FDG PET In Assessing Clinical Status Changes On Pediatric Patients With Epilepsy

Objective2-fluorine-18-fluoro-2-deoxy-D-glucose(¹⁸F-FDG)with position emission tomography（PET）has been widely used in preoperative localization of epileptic focus on epilepsy patients,but the relationship between changes in brain glucose metabolism measured with PET and clinical status of pediatric epilepsy patients is not fully understood.The aim of this study was to investigate the correlation between glucose metabolic changes of cortex metabolism abnormalities and subcortical structures and clinical condition changes on pediatric epilepsy patient.MethodsThis study retrospectively included 30 pediatric patients with epilepsy who have detailed clinical data and underwent two ¹⁸F-FDG PET examinations.Another 21 children with normal brain glucose metabolism were included as the control group.¹⁸F-FDG PET images were analyzed at individual level by using visual assessment combined with statistical parametric mapping（SPM）,then the changes of extent and degree in abnormal glucose metabolism regions were measured and correlated to clinical condition changes.Correlation analysis between variables was performed using Pearson or Spearman rank correlation method.Stepwise multivariate linear regression analysis was used to evaluate the effect of clinical epilepsy-related factors on PET variables.The two-sample t test was used when variables with normal distribution,while the Mann-Whitney U test was used when variables did not show normal distribution.Chi-square test was performed to compare the count data between the groups.An alpha level of P=0.05 was considered as the limit of significance.ResultsAccording to the change on seizure frequency between the two ¹⁸F-FDG PET scans,the patients were divided into improvement group（19 cases）and persistent or progression group（11 cases）.There was a significant difference in the changes of asymmetry index（AI）and volume in the cortical abnormal glucose metabolism between the two groups（all P<0.05）.Compared with the first PET scan,84%（16/19）pediatric epilepsy patients whose seizure frequency had decreased showed a decrease in the|AI|of abnormal areas in cortex on the second PET scan,and the extent of cortical metabolic abnormalities also decreased in 74%（14/19）.In contrast,patients with persistent or increased seizure frequency may show an increase both in extent and|AI|of cortical metabolic abnormalities.Compared to children with normal brain glucose metabolism,pediatric epilepsy patients had lower glucose metabolism in the striatum and thalamus（all P<0.05）.There was a significant difference in glucose metabolism of the bilateral caudate nucleus and thalamus between the improvement group and the persistent or progression group（all P<0.01）.Higher glucose metabolism of caudate nucleus and thalamus than before was seen on 63%-79%pediatric epilepsy patients with decreased seizure frequency,while73%-100%patients whose seizure frequency had persistent or increased showed lower glucose metabolism of these regions.ConclusionThe dynamic changes of glucose metabolism on pediatric epilepsy patient can be effectively evaluated by longitudinal ¹⁸F-FDG PET.According to the alternations of clinical condition in pediatric epilepsy patients,changes of glucose metabolism will be seen both on cortex and subcortical structures on PET.PET may be expected to become an imaging marker in evaluating the clinical status of pediatric epilepsy patient in vivo.