Abstracts

Rationale: Experimental and histopathological data suggest that neuroinflammation plays an important role in the pathogenesis of epilepsy. We performed PET scanning with [¹¹C]-[R]-PK-11195 (PK, which binds to translocator protein expressed by activated microglia) to evaluate potential neuroinflammation in children with various epileptic disorders.Methods: Thirty-seven children with various epileptic disorders (Mean age: 7.5 4.6 years, 19 females) underwent dynamic PK PET scanning. The PET images were evaluated visually, as well as quantitatively, by calculating binding potential (PK receptor binding), a measure of neuroinflammation. Cluster analysis was used to calculate the input function. The data were compared with those from 10 pediatric controls (mean age: 8.8 5.2 years; 5 males), in whom suspicion of neuroinflammation was eventually ruled out based on available clinical, biochemical and radiological data.Results: The PK binding was found to be increased in various cortical and sub-cortical structures in 8/8 children with suspected encephalitis, including 6 with Rassmussen's encephalitis, 8/8 with epileptic spasms, 3/4 with status epilepticus, and 9/17 with intractable complex partial seizures, suggesting underlying neuroinflammation in these regions. The highest binding potential was seen in a patient with encephalitis and uncontrolled seizures [0.79 (N= 0.01-0.07)] (see figure).Conclusions: Our study shows neuroinflammation in a large number of children with epileptic disorders. PK PET may provide a useful in vivo biomarker for the study of epilepsy and possibly epileptogenesis. In vivo detection of neuroinflammation with PET may be useful eventually in elucidating and subsequently guiding therapeutics aimed at the inflammatory process in epilepsy.