Magnetic resonance imaging and spectroscopy in Parkinson's disease.

At present, conventional MR imaging shows no convincing structural changes in PD itself but may be useful in helping to distinguish PD from other neurodegenerative parkinsonian syndromes and from the occasional case of parkinsonism secondary to a focal brain lesion. MR spectroscopy may also provide useful information in distinguishing PD from disorders such as MSA. The general field of MR imaging and spectroscopy is evolving rapidly, and there are a number of areas in which we can expect new developments to provide relevant information. Novel pulse sequences may provide more information regarding substantia nigra pathology in PD. The use of MR as a tool to measure regional iron concentrations should provide more information regarding the relationship between iron accumulation and parkinsonian symptoms. MR spectroscopy provides a sensitive tool for the researcher to investigate in vivo the possible contribution of abnormalities in brain energy metabolism to the pathogenesis of PD. Spectroscopy also allows the assessment of other metabolite changes in PD, for example, providing for the evaluation of the potential importance of changes in regional brain glutamate content. Last, although not considered in the present review, functional MR imaging provides the potential to evaluate, in a noninvasive fashion, the role played by the basal ganglia in motor control and in cognition in normal individuals as well as in PD.