Diffusion tensor imaging in idiopathic Parkinson's disease and multisystem atrophy (Parkinsonian type).

BACKGROUND: Differentiation between Parkinson's disease (PD) and atypical Parkinson syndromes (AP) is usually based on clinical examination, but can be challenging especially at early stages of the diseases. Diffusion tensor imaging (DTI) allows for differentiation between PD and AP with good specificity. It is a promising tool for clinical application, but has not been elaborated completely with respect to methodology and validity. OBJECTIVE: In this study we evaluated differences of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) within white brain matter between patients with PD and multisystem atrophy of the parkinsonian type (MSAp). MATERIALS AND METHODS: DTI data of 9 PD and 9 MSAp patients were compared by means of a hypothesis-free whole-brain analysis algorithm (TBSS) focusing on changes within white matter. RESULTS: We found significantly higher values of the ADC in the MSAp group in the anterior limb of the inner capsule, superior parts of the corona radiata, and lateral periputaminal white matter. Group differences in FA values were not significant. CONCLUSION: Changes of the ADC close to the putamen proved most consistent and seem to be promising for the ongoing clinical implementation of DTI for the differentiation of hypokinetic-rigid movement disorders.