TY - JOUR T1 - [<sup>11</sup>C]PK11195-PET to image neuroinflammation in focal epilepsy JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1203 LP - 1203 VL - 52 IS - supplement 1 AU - Anat Maoz AU - Shankar Vallabhajosula AU - Masanori Ichise AU - Stanley Goldsmith AU - Fahad Pervez AU - Paresh Kothari AU - David Silbersweig AU - Emily Stern AU - Tracy Butler Y1 - 2011/05/01 UR - http://jnm.snmjournals.org/content/52/supplement_1/1203.abstract N2 - 1203 Objectives An association between neuroinflammation and epilepsy is increasingly recognized. There is increasing evidence that seizure-related microglial activation predisposes to future seizures, and may therefore play a role in epileptogenesis. We are assessing the potential role of [11C]PK11195 (PK), a radiotracer that binds specifically to peripheral benzodiazepine receptors (PBR) on activated microglia to image neuroinflammation in epileptic foci. Previous studies have documented that PK-PET is useful to identify neuroinflammatory foci in patients with several neurological disorders. Methods Patients (n=5) with refractory focal epilepsy with normal or near normal MRI and healthy controls (n=3) received 10-15 mCi of PK. Dynamic images of brain were acquired for 60 minutes in 3-D mode. Two-parameter linearized reference tissue model, MRTM2 (ichise et al. J Cerebral Blood Flow &amp; Metabolism, 2003) implemented in PMOD with cerebellum as a reference region was used to generate parametric images of PK binding relative to cerebellum (termed Differential Binding Index - DBI). Results Similar to healthy controls, DBI images in majority of patients show expected increased relative uptake in thalamus and brainstem, as well as extensive extracranial uptake. One of the patients showed a discrete focus of increased PK uptake in R frontal lobe, corresponding to her seizure focus as identified by EEG, FDG PET, and ictal FDG PET. In addition, 2/5 patients showed subtle, but increased PK uptake in seizure foci . Conclusions This data suggests that increased focal PK uptake may potentially be useful to identify inflammation in foci corresponding to epileptic foci. However, nonspecific binding and reduced signal-to-noise ratio makes PK-PET quantitative analysis challenging. Therefore the use of mathematical methods to analyze PK11195 images is crucial and still under active development and assessment. Research Support Supported by CURE &amp; NIH K23 NS05757 ER -