Neurodegenerative Disorders

A large group of acquired and inherited disorders whose etiology are incompletely understood, are difficult to diagnose, and have limited treatment options, but with a unifying feature of gradual synaptic and neuronal loss producing cognitive symptoms. The clinical presentations of these disorders are associated with characteristic patterns of neuronal degeneration, such as Tau, Amyloid-Beta (Aβ), and α-synuclein aggregates. The following sections will feature the common and several less common neurodegenerative disorders, and highlight distinguishing imaging features. Overlap of both clinical and imaging manifestations of these disorders often limits definitive diagnosis on an imaging basis, with imaging used to exclude other disorders, and to some extent distinguish between the different neurodegenerative disorders. A further complication is the growing evidence that co-pathology of multiple neurodegenerative disorders may be more common than a single, pure neurodegenerative disorder in aging individuals. Multiple classification schemes exist based on clinical presentation, pathology, and imaging, and disorders will be highlighted that appear in multiple categories.