Technology insight: imaging neurodegeneration in Parkinson's disease

Currently, the clinical diagnosis of Parkinson's disease (PD) can be problematic, particularly at the early stages of the disease when the full spectrum of symptoms and signs might not yet be manifest. In addition, the mechanisms that underlie the nonmotor complications of PD, such as dementia and depression, are poorly understood, despite the fact that these symptoms largely determine the patient's quality of life at the end stage of the disease. This article reviews the latest advances in structural and functional imaging that have provided important insights into the structural, pathophysiological and pharmacological changes associated with PD. The contribution of inflammatory processes to the pathology of PD is discussed, as are the various possible mechanisms that lead to coexistent dementia and depression.