10 - Movement Disorders: Parkinson's Disease

Abstract

This chapter reviews the recent advances in positron emission tomography (PET) studies of Parkinson's disease (PD) as well as the relative advantages and shortcomings of these techniques in clinical diagnosis and management. PET techniques may greatly advance the understanding of the pathophysiology of PD and the functional changes that occur with successful therapy. Functional brain imaging with PET has provided novel insights into the pathophysiology of (PD) and other movement disorders. In PD, PET has been applied in the investigation of nigrostriatal presynaptic dopaminergic nerve terminals to measure dopa decarboxylase activity using [18F] fluorodopa (FDOPA). FDOPA is probably the most commonly applied radiotracer for the study of striatal dopaminergic nerve terminals in parkinsonism. PET studies with this tracer measure the rate of decarboxylation of [18F] fluorodopa to [18F] fluorodopamine by the enzyme dopa decarboxylase (DDC) and its subsequent storage in the striatal dopaminergic nerve terminals. Considerable attention has been dedicated to the development of novel data analytical methods for the characterization and quantification of neural networks in functional brain imaging data. Such metabolic covariance patterns may serve as clinically useful markers of disease severity as well as aid in the differential diagnosis of parkinsonism. Moreover, new radiotracer techniques have been developed to quantify neurochemical deficits associated with neurodegenerative processes.