Comparison of dopamine transporter decline in a patient with Parkinson's disease and normal aging effect

We report serial dopamine transporter (DAT) positron emission tomography (PET) scanning in a patient with Parkinson's disease (PD). Six months after motor symptom onset, the patient was diagnosed with PD, Hoehn-Yahr stage 1 at age 71, and underwent DAT PET scanning at ages 71, 72, 74, and 75. Volumes-of-interest were placed on the ventral striatum (vST), pre-commissural dorsal caudate (preDCA), post-commissural caudate (postCA), pre-commissural dorsal putamen (preDPU), and post-commissural putamen (postPU); the results were compared to the age-related regression line created by using the data of 16 healthy subjects. For the patient, DAT availability in the vST, preDCA, postCA, preDPU, and postPU at the first scanning was 5.5%, 26.2%, 29.9%, 34.5%, and 60.2% lower, respectively, compared to the age-related regression line. The rates of DAT decline in the vST, preDCA, postCA, preDPU, and postPU were 5.3%, 5.4%, 8.5%, 6.2%, and 7.8% per year, respectively. The postPU is well known to be an initial region of DAT decline and be severely affected throughout the illness. If the decline follows an exponential pattern, in this case, DAT decline in the postPU is speculated to start about 10 years before the motor symptom onset.