Abstracts

Changes in metabolism due to the differences of cerebral blood flow during ictal and interictal period can be quite various when observed by 2-deoxy-2-[¹⁸F]fluro-D-glucose(FDG)-PET. So, we performed EEG and PET concurrently to evaluate the effect of epileptiform and non-epileptiform discharge of EEG on glucose metabolism. We tried to reduce the rate of false lateralization of PET reading and evaluate the relationship between EEG and PET result, thus deciding the appropriateness of concurrent study of PET and PET-EEG along with the importance of PET-EEG in diagnosing and localizing a lesion. 73 children with pediatric epilepsy who received PET and PET-EEG simultaneously were included in our study. We studied their clinical aspects of seizure, the severity of focal slow wave during interictal period with the frequency and localization of polyspike or sharp wave to compare with the result of PET. Also, we evaluated the relationship between pathologic results and the concurrency rate between PET and PET-EEG in patients who received operation. 73 patients received PET and PET-EEG concurrently. Their sex ratio was 1.8:1. When grouping the patients according to the site of the lesion in EEG, 53 children proved to have a local lesion showing the ratio of 2.7:1 to children without it. Among 53 children, 27 had focal seizure while 26 had secondary encephalopathy. The frequency of epileptiform discharge was 18% in no/rare, 10% in occasional, and 72% in frequent group while showing 0%, 43% and 68% rate of concurrency with PET each with high correlation (p = 0.001, r= 0.491). Severity of non-epileptiform discharge was classified as no, mild, moderate, and severe and were 21%, 34%, 23%, and 22% of the whole group along with 13%, 52%, 65%, 69% of concurrence rate (p= 0.001,r=0.365). According to EEG study, 29% of focal lesion was located in frontal, 14% in centrotemporal, and 8% in occipital area. 22% showed lateralization and 27% without it. The rate of concurrency between epileptiform discharge and PET according to the location of focal lesion was 67%, 80%, 67%, 75%, and 5%(p=0.001). The same rate was 57%, 30%, 50%, 88%, 25%(p=0.002) between non-epileptiform discharge and PET showing certain difference. 10 patients went through operation. 6 showed concurrent result in PET and PET-EEG and 4 out of them had concurrency with 24hr video EEG and brain MRI as well. They had no seizure event after the surgery and proved to have cortical microdysgenesis or dysplasia in pathologic evaluation. Epileptiform discharge and non-epileptiform discharge in EEG showed certain association with hypometabolim in PET study. In conclusion, we recommend PET-EEG to reduce false lateralization and to localize lesion in cases of high frequency or severity.