Monitoring therapeutic effects in Parkinson's disease by serial imaging of the nigrostriatal dopaminergic pathway.

PET and SPECT are very sensitive techniques to detect in-vivo nigrostriatal degeneration in Parkinson's disease, even in the pre-motor phase of the disease. Furthermore, these techniques are able to measure disease progression. However, caution must be used in the interpretation of studies in which therapeutic effects in Parkinson's disease were also monitored by serial imaging of nigrostriatal neurons, as disparity between imaging and clinical outcomes has been reported in several clinical studies.