Figure 1.

Neuroimaging Biomarkers

Neuroimaging techniques are reviewed. A, Single-photon emission computed tomography (SPECT) imaging in controls and those with early-stage, moderate, and late-stage Parkinson disease (PD; reprinted with permission from Schapira and Olanow¹). B, Positron emission tomography (PET) fluorodopa imaging in controls and those with early-stage and late-stage PD (reprinted with permission from Schapira and Olanow¹). C, Free-water imaging longitudinally over 4 years in an individual with de novo PD (provided with courtesy of Roxanna Burciu, PhD [Department of Kinesiology and Applied Physiology, University of Delaware, Newark], and used with permission). D, Neuromelanin-sensitive imaging in a healthy control and patient with PD (disease duration of 4 years; reprinted with permission from Biondetti et al²). E, Absence of the nigrosome formation hypointensity using iron-sensitive imaging in a patient with idiopathic rapid eye movement sleep behavior disorder (reprinted with permission from De Marzi et al³). F, Distribution of atrophy in a patient with PD measured by deformation-based morphometry (reprinted with permission from Zeighami et al⁴).