Magnetic resonance imaging (MRI) methods in Parkinson’s disease

Introduction The revolution created by magnetic resonance imaging (MRI) is a result of its ability to utilize the intrinsic differences in the magnetic properties of tissues to provide information about function, structure, and chemistry. This book provides background on a variety of MRI methods and focuses on their application to neurological conditions that manifest with movement disorders. These disorders include neurodegenerative conditions such as Parkinson's disease (PD), Huntington's disease, and ataxia which are characterized by progressive neuronal loss with accompanying neuropathological changes. Meanwhile other movement disorders are not clearly degenerative and tend to have more subtle structural, functional, and neurochemical changes. The focus of many chapters herein will be on PD, which constitutes the second most common neurodegenerative disease after Alzheimer's disease (AD), and is the principle focus of many clinicians and researchers in the movement disorders field. It is stated that approximately 1% of those over 65 years of age have PD [1]. As a result there is substantial focus on PD research, and the discoveries made in basic neuroscience that relate to pathogenic mechanisms of PD (or AD for that matter) are often relevant for lesser known neurodegenerative parkinsonian conditions such as multiple system atrophy (MSA) or progressive supranuclear palsy (PSP). Along with the progress made in basic science research, MRI developments have been applied to PD and have begun to show promise as a surrogate biomarker in research studies. As well these techniques may be more useful clinically in looking at other parkinsonian conditions such as MSA and PSP. While MRI is presently not able directly to image dopaminergic neuronal loss that underlies degenenerative parkinsonian conditions, it can provide complementary data to those obtained with nuclear tracer imaging. First, this chapter will provide an overview of MRI methods which will be discussed in much greater depth in subsequent chapters, and we will cover nascent techniques that we are employing at the University of Minnesota that may ultimately help provide an imaging biomarker of disease.