An FP-CIT PET comparison of the differences in dopaminergic neuronal loss between idiopathic parkinson disease with dementia and without dementia

Previous studies have demonstrated a decreased density of dopamine transporters (DAT) in basal ganglia in patients with idiopathic Parkinson disease (IPD) using I-n-fluoropropyl-2b-carbomethoxy-3b-(4-iodophenyl) nortropane (FP-CIT), and the reductions in striatal DAT levels were inversely correlated with the severity of motor dysfunction in IPD. However, there has been no study on the correlation of DAT levels between IPD patients with and without cognitive dysfunction. Thus, we evaluated the differences in regional DAT density in the brain of patients with IPD without dementia and those with dementia using FP-CIT positron emission tomography. We recruited 24 consecutive patients with IPD, including 7 with IPD without dementia and 17 with IPD with dementia, and 18 healthy controls. FP-CIT positron emission tomography scans were acquired 90 and 210 minutes after the FP-CIT injection. The DAT density did not differ in the caudate nucleus or the putamen between patients with IPD without dementia and those with dementia. However, the DAT density between the 2 groups with IPD demonstrated a significantly decreased density compared with that of healthy controls in the putamen. We cautiously suggest that there is no relationship between DAT density and cognitive severity because there were no significant differences in the DAT density between IPD with dementia and those without dementia.