Neuroimaging in Parkinson's disease.

Structural imaging studies often reveal relatively limited findings in Parkinsonian disorders, as the most profound changes are neurochemical and hence better revealed by functional studies such as PET or SPECT. However, newer magnetic resonance techniques such as spectroscopy, diffusion weighted imaging, diffusion tensor imaging and magnetization transfer have shown promise in differentiating between idiopathic Parkinson's and the atypical parkinsonian disorders such as multiple system atrophy and progressive supranuclear palsy. We review here recent advances in functional imaging as well as in structural studies of basal ganglia disorders. Functional studies may give insights into mechanisms underlying disease pathogenesis, as well as neurochemical alterations.