Amyloid binding with the novel ligand [18F]florbetapir. Axial, sagittal and coronal [18F]florbetapir average images show typical amyloid images in controls and Alzheimer's disease (AD) patients. Blue arrows, cortical uptake; red arrows, white matter (WM) uptake. A negative [18F] florbetapir scan is characterized by a low cortical uptake and high uptake in the adjacent WM. An abnormal scan is characterized by a focal increase of cortical [18F]florbetapir uptake. Increased cortical uptake is evidenced by the reduction between cortical to WM contrast in at least two brain areas. A negative scan indicates sparse to no neuritic plaques, and is inconsistent with a neuropathological diagnosis of AD at the time of image acquisition. A negative scan thus implies reduced likelihood of clinical AD. A positive [18F]florbetapir scan indicates a neuropathology consistent with the presence of moderate to frequent amyloid neuritic plaques. However, the interpretation of a positive scan should take into consideration that amyloid neuritic plaques may also be found in patients with other types of neurologic conditions as well as older people with normal cognition. Images obtained from Alzheimer's Disease Neuroimaging Initiative (ADNI) and processed at PR-N's laboratory.