Off-Target F-AV-1451 Binding in the Basal Ganglia Correlates with Age-Related Iron Accumulation.

Off-target binding in the basal ganglia is commonly observed in the F-AV-1451 PET studies of the elderly. We sought to investigate the relationship between this phenomenon in the basal ganglia and iron accumulation using iron-sensitive R* MRI. Fifty-nine healthy controls and 61 patients with Alzheimer disease and mild cognitive impairment underwent F-AV-1451 PET and R* MRI studies. A correlation analysis was performed for age, F-AV-1451 binding, and R* values. There was an age-related increase in both F-AV-1451 binding in the basal ganglia and R* values in the putamen in both the controls and the Alzheimer disease/mild cognitive impairment patients. F-AV-1451 binding in the basal ganglia increased with R* values. Off-target F-AV-1451 binding in the basal ganglia is associated with the age-related increases in iron accumulation. Postmortem studies are required to further investigate the nature of this association.