Increased basal ganglia binding of ¹⁸F-AV-1451 in patients with progressive supranuclear palsy

Background: Progressive supranuclear palsy (PSP) is difficult to diagnose accurately. The recently developed tau PET tracers may improve the diagnostic work-up of PSP. Methods: Regional tau accumulation was studied using ¹⁸F-AV-1451 PET in 11 patients with PSP and 11 age-matched healthy controls in the Swedish BioFinder study. Results: ¹⁸F-AV-1451 standard uptake volume ratios were significantly higher in the basal ganglia in PSP patients when compared with controls (globus pallidus 1.75 vs 1.50; putamen 1.51 vs 1.35). Retention in the basal ganglia was correlated with age in both groups (r=.43-.78, P<.05). In PSP, we observed a significant correlation between clinical deterioration measured with the PSP rating scale and standard uptake volume ratios in the globus pallidus (r=.74, P<.05). However, no ¹⁸F-AV-1451 retention was observed in the cerebral cortex or white matter of either PSP patients or controls, and autoradiography did not reveal any specific binding of AV-1451 to PSP tau aggregates. Conclusion: We found higher ¹⁸F-AV-1451 retention in the basal ganglia of PSP patients when compared with healthy elderly controls, but also increases with age in both controls and patients. As a result of the overlap in retention between diagnostic groups and the age-dependent increase present also in controls, ¹⁸F-AV-1451 PET might not reliably distinguish individual patients with PSP from controls. However, further studies are needed to evaluate whether ¹⁸F-AV-1451 PET might be useful as a progression marker in clinical PSP trials.