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| Figure Legend: Axial sections of MR and 11C-PBR28 from a single healthy subject. Note the spatial correspondence in PET images of the focus of high uptake (arrows), representing uptake in the choroid plexus. Background: Animal studies and clinical observations suggest that epilepsy is associated with inflammation. Translocator protein 18 kDa (TSPO), a marker of inflammation, is increased in surgical samples from patients with temporal lobe epilepsy. TSPO can be measured in the living human brain with PET and the novel radioligand 11C-PBR28. In this study, we sought to determine if in vivo expression of TSPO is increased ipsilateral to the seizure focus in patients with temporal lobe epilepsy. Sixteen patients with unilateral temporal lobe epilepsy and 30 healthy subjects were studied with 11C-PBR28 PET and MRI. Uptake of radioactivity after injection of 11C-PBR28 was measured from regions of interest drawn bilaterally onto MR images. We found that brain uptake was higher ipsilateral to the seizure focus in the hippocampus, parahippocampal gyrus, amygdala, fusiform gyrus, and choroid plexus, but not in other brain regions. This asymmetry was more pronounced in patients with hippocampal sclerosis than in those without. We found increased uptake of radioactivity after injection of 11C-PBR28 ipsilateral to seizure focus in patients with temporal lobe epilepsy, consistent with increased expression of TSPO. These preliminary findings suggest that TSPO imaging may be key to the pathophysiology and treatment of temporal lobe epilepsy (Hirvonen et al, 2012a) PDF. References: Hirvonen, W.C. Kreisl, M. Fujita, I. Dustin, S. Miranda, Y. Zhang, C. Morse, V.W. Pike, R.B. Innis, and W.H. Theodore. Increased in vivo expression of an inflammatory marker in temporal lobe epilepsy. J. Nucl. Med. 53: 234-240, 2012a. (PDF File) |
