Contribution of neuroimaging studies to the understanding of immunology and inflammation in epilepsy

There is a close relationship between epilepsy and neuroinflammation, and increasing evidence demonstrates the involvement of brain inflammation in the process of epileptogenesis including dysfunction of the blood-brain barrier (BBB) and glutamate hyperexcitability. In vivo neuroimaging is a useful and less-invasive tool to examine human brains. Several powerful imaging modalities have been used to investigate the relationship between neuroinflammation and epilepsy, including positron emission tomography (PET) and 1H-magnetic resonance spectroscopy (MRS). PET can capture molecular structures and metabolism in the brain with the use of radioactive tracers such as 18-kDa translocator protein (TSPO)–related tracers for immune cells, (R)-11C-verapamil for the BBB, and radiotracers for glutamate receptors. 1H-MRS provides information about neural metabolites of the brain (e.g., N-acetyl aspartate, creatine, and myo-inositol). 1H-MRS and diffusion-weighted imaging allow us to measure the brain's temperature. This chapter focuses on the utility and current findings of these imaging modalities in epilepsy and neuroinflammation.