The contribution of possible MAO-B binding to the [<sup>18</sup>F]-THK5351 signal needs to be further evaluated, but nevertheless [<sup>18</sup>F]-THK5351 PET may still serve as valuable biomarker for diagnosis of PSP.
MAOB levels were increased in degenerating putamen (+83%) and substantia nigra (+10%, non-significant) in multiple system atrophy; in caudate (+26%), putamen (+27%), frontal cortex (+31%) and substantia nigra (+23%) of progressive supranuclear palsy; and in frontal cortex (+33%), but not in substantia nigra of Parkinson's disease, a region we previously reported no increase in astrocyte protein markers.