ADORA2A and Parkinson disease: We hypothesized that if the beneficial effects of coffee in PD are mediated by caffeine through A2AR antagonist action, a substantial amount of A2AR should be occupied by caffeine after coffee intake, similar to that observed after administration of istradefylline.11, 12 This study aimed to test the hypothesis by calculating occupancy rates of striatal A2ARs after coffee intake in patients with PD using 11C‐preladenant positron emission tomography (PET) for measurement of A2AR availability.