Brain MRI in Parkinson s disease

In this review article, conventional brain MRI and advanced MRI techniques in Parkinson's disease (PD) are discussed, with emphasis on clinical relevance. Conventional brain MRI sequences generally demonstrate limited abnormalities specific for PD and in clinical practice brain MRI is mainly used to exclude other pathology. Possibly, brain MRI at higher magnetic field strengths could provide new diagnostic markers. In recent years, new imaging techniques such as susceptibility weighted imaging (SWI), diffusion (tensor) MRI, magnetization transfer imaging (MTI), and functional MRI (f-MRI) have been applied to patient cohorts with PD to improve understanding of pathophysiologic changes, including functional connectivity. These advanced MRI techniques hold promise to provide additional diagnostic markers for early stage PD, as demonstrated by diffusional changes in the orbital-frontal region in the pre-motor phase of PD. Whether these advanced MRI techniques provide new diagnostic markers for early stage PD, remains a debate. Standardization of scanning protocols and post-processing methods, and validation of diagnostic criteria is crucial for these advanced MRI techniques. For this, well designed prospective clinical cohort studies are needed.