A review of diagnostic imaging approaches to assessing Parkinson's disease

Parkinson's Disease (PD) is a pervasive, chronic, progressively debilitating neurodegenerative disorder that commonly presents with a series of motor-related symptoms, including resting tremor, stiffness, bradykinesia, and issues with balance and reflexes leading to postural instability and an impaired gait. Since it's official classification, much has been studied regarding the clinical features, etiology, and neuropathophysiology of PD. An array of similar conditions, known as Parkinsonian syndromes, have also been identified. In addition to the clinical presentation of motor and non-motor related symptoms, histological analyses have revealed the presence of protein clusters and cellular changes in the brain that are indicative of PD. Since histology is necessarily performed post-mortem on the patients sectioned brain, it is not of use in diagnostic purposes. However, with the use of medical imaging technologies, particularly magnetic resonance imaging (MRI) and nuclear medicine imaging techniques, characteristic morphological and metabolic changes in the brain, which occur in the earlier stages of the disease, have been uncovered. Despite these technological advancements, PD is still typically diagnosed via clinical analysis. With the uncertainty associated with this technique, and the development of observable motor-related symptoms occurring after a significant amount of neurodegeneration, diagnosis of PD in its early stages is not possible. A review of the diagnostic imaging approaches to assessing PD could spread awareness of their efficacy and their potential for earlier diagnosis. Not only could this information inform public health policy in a similar manner to the recommendations for mammographic scans, the early diagnosis of PD is necessary for the implementation of any potential interventions.