Imaging of neuroinflammation in adult Niemann-Pick type C disease: A cross-sectional study.

OBJECTIVE:To test the hypothesis that neuroinflammation is a key process in adult Niemann-Pick type C (NPC) disease, we undertook PET scanning utilizing a ligand binding activated microglia on 9 patients and 9 age- and sex-matched controls. METHOD:We scanned all participants with the PET radioligand 11C-(R)-PK-11195 and undertook structural MRI to measure gray matter volume and white matter fractional anisotropy (FA). RESULTS:We found increased binding of 11C-(R)-PK-11195 in total white matter compared to controls (p < 0.01), but not in gray matter regions, and this did not correlate with illness severity or duration. Gray matter was reduced in the thalamus (p < 0.0001) in patients, who also showed widespread reductions in FA across the brain compared to controls (p < 0.001). A significant correlation between 11C-(R)-PK11195 binding and FA was shown (p = 0.002), driven by the NPC patient group. CONCLUSIONS:Our findings suggest that neuroinflammation-particularly in white matter-may underpin some structural and degenerative changes in patients with NPC.