Imaging brain inflammation in epilepsy

Epilepsy is a highly common chronic neurological disorder. Although symptomatic treatment is available, 30-40% of epilepsy patients still remain resistant to anti-epileptic drugs. The primary identification and extensive characterization of the pathological substrates underlying epilepsy would facilitate the development of novel treatments, including disease-modifying and anti-epileptogenic therapies. A plethora of evidence points toward an undeniable role of brain inflammation in epileptogenesis. However, the exact role of this process remains unfortunately not clear. Non-invasive imaging of brain inflammation can promote our fundamental knowledge, which may lead to better insights into the role of brain inflammation in disease ontogenesis. Moreover, it will allow us to investigate whether the visualization of this process can serve as a validated biomarker for epilepsy. In turn, such can lead to major perspectives regarding the development and evaluation of anti-inflammatory treatments, and screening possibilities for patients at risk. Here, we first discuss the applications for imaging of the different brain inflammation constituents. Secondly, we review the available approaches for molecular imaging of brain inflammation in general and finally present the current research on the imaging of brain inflammation in patients and experimental models of epilepsy. The current imaging toolbox is limited by the range of neuroinflammatory targets, which can be visualized at present, and in addition, the often indirect approaches used. We believe that research in this field will further advance as highly specific ligands, and producible and practical imaging approaches will become available.