PET imaging of microglia activation in neuropsychiatric disorders with potential infectious origin

Abstract

The CNS is an immunoprivileged location for the possible sequestration of latent infections. The presence of pathogens may be involved in the etiology of neuropsychiatric diseases by inducing classical infl ammatory responses, hypersensitivity, cellular toxicity, or direct alteration of cellular processes. Infection, persistence, and activation of microbes in the brain are not easy to assess in vivo, and the relation with clinical disease is very diffi cult to prove. An elegant way to determine an infl ammatory response in the brain in vivo is by molecular imaging of microglia activation with [ 11 C]PK11195. In this chapter we summarize the [ 11 C]PK11195 PET imaging studies already conducted in neuropsychiatric diseases, and we propose the application of PET imaging with nitroimidazole radiopharmaceuticals to measure infectious processes in the human brain directly.