Positron emission tomography imaging of neuroinflammation.

Injury to the central nervous system is characterized by localization of activated microglia at the site of injury. The peripheral benzodiazepine receptor expressed on the outer mitochondrial membrane of the activated microglia is a sensitive biomarker for the detection of this neuroinflammatory response to an insult. PK11195, an isoquinoline ligand that specifically binds peripheral benzodiazepine receptor, can be tagged with a positron emitter and used as a tracer for molecular imaging of this receptor in vivo by positron emission tomography (PET). [(11)C](R)PK11195 has been used in the imaging of various neuroinflammatory disorders, such as Alzheimer disease and multiple sclerosis. On the basis of our small-animal PET imaging studies using a neonatal rabbit model of maternal inflammation-induced cerebral palsy, we propose that PET imaging using [(11)C](R)PK11195 may be a valuable tool for detecting neuroinflammation in the brain of newborns born to mothers with chorioamnionitis.