Imaging of activated microglia with PET and [¹¹C]PK 11195 in corticobasal degeneration

Abstract

Positron emission tomography (PET) using [(11)C]PK 11195, a ligand for peripheral benzodiazepine receptor binding sites, offers the opportunity to image activated microglia in vivo. This tool may therefore be used to display the occurrence of microglial activation in the course of neurodegeneration. A patient with the clinical diagnosis of corticobasal degeneration (CBD) and left-sided symptoms was studied using fluorodeoxyglucose (FDG) and [(11)C]PK 11195 PET. We found a marked right hemispheric hypometabolism and asymmetric microglial activation in corresponding areas of the basal ganglia and right temporal and parietal cortex. [(11)C]PK 11195 PET suggests involvement of microglial activation in the pathogenesis of CBD.

Neuroimaging of PD, PSP, CBD and MSA—PET and SPECT studies

“…Henkel and colleagues [10] reported a similar finding. This pattern of increased [ 11 C](R)-PK11195 binding corresponds well with the known distribution of neuropathologic changes in CBD.…”

Microglia display modest phagocytic capacity for extracellular tau oligomers

“…Distribution of activated microglia parallels that of tau deposits in human AD [12–16] and non-AD tauopathies such as tangle-predominant dementia, progressive supranuclear palsy, corticobasal degeneration and Pick’s disease [17–21]. Activated microglia have been frequently present in the proximity of neurofibrillary tangles at early and late stages of tangle formation, which suggests a close relationship between inflammatory response and tau neurofibrillary lesions [14].…”

Quantification of (R)-[11C]PK11195 binding in rheumatoid arthritis

“…In the brain, (R)- [ 11 C]PK11195 binds to activated microglia [7] which are part of the brain's immune system. (R)- [ 11 C] PK11195 has been used extensively to image brain inflammation using PET [8][9][10][11][12][13][14][15][16]. Methods have been published regarding the quantification of (R)- [ 11 C] PK11195 binding in the brain [17][18][19].…”