Functional imaging in Huntington disease.

Functional imaging has been increasingly used in the study of neurodegenerative diseases as such techniques can elucidate neurochemical and functional changes that cannot be captured with structural imaging. Unlike other neurodegenerative diseases, in Huntington disease (HD) genetic testing allows for diagnostic certainty. Thus, the focus has been on understanding the pathophysiogic processes underlying the development of the disease, as well as the identification of potential biomarkers to monitor disease progression, particularly during the presymptomatic stage. These imaging methods have expanded our understanding of HD beyond dopaminergic deficits and striatal cell loss, and have described alteration in widespread networks relating to motor and cognitive symptoms. In this chapter, we review the current literature on radiotracer and functional magnetic resonance imaging relating to HD.