Monoamine Oxidase B Binding of 18F-THK5351 to Visualize Glioblastoma and Associated Gliosis: An Autopsy-Confirmed Case.

An 86-year-old woman with cognitive impairment and left hemiparesis underwent F-THK5351 PET 4 months before her death. In addition to "normal" off-target binding in the basal ganglia, abnormal accumulation was observed along the pyramidal tract and around the right basal ganglia as ring-shaped uptake that overlapped a gadolinium-enhanced lesion. Postmortem pathological examination revealed that she had glioblastoma multiforme with associated gliosis, in which monoamine oxidase B (MAO-B) activity is increased. In vitro autoradiography of the corresponding lesion demonstrated specific binding of F-THK5351, which was blocked by an MAO-B-selective ligand. Thus, F-THK5351 PET may reflect glioblastomas and associated gliosis by binding to MAO-B.