Complete and readily reversible blocking of striatal DaTscan binding by methylphenidate.

An 80-year-old man with Parkinson disease underwent DaTscan imaging, which showed no detectable uptake in the basal ganglia but normal background uptake in other parts of the brain and in the chest and abdomen. It was later found that the patient was taking methylphenidate. The second study performed 3 weeks later after discontinuing methylphenidate for 48 hours showed good uptake in the striatum. Our results indicate that methylphenidate may completely block physiologic uptake of DaTscan in the striatum and that this effect can be effectively reversed after discontinuing the medication for a short period.