The 2011 National Institute on Aging-Alzheimer's Association diagnostic guidelines (1, 2) also include biomarkers for the pathophysiologic process of Alzheimer disease: A low level of beta-amyloid in cerebrospinal fluid (CSF) Beta-amyloid deposits in the brain detected by positron emission tomography (PET) imaging using radioactive tracer that binds specifically to beta-amyloid plaques (eg, Pittsburgh compound B [PiB], florbetapir) Other biomarkers indicate downstream neuronal degeneration or injury: Elevated levels of tau protein in CSF or tau deposits in the brain detected by PET imaging using radioactive tracer that binds specifically to tau Decreased cerebral metabolism in the temporoparietal cortex measured using PET with fluorine-18 (18F) - labeled deoxyglucose (fluorodeoxyglucose, or FDG) Local atrophy in the medial, basal, and lateral temporal lobes and the medial parietal cortex, detected by MRI These findings increase the probability that dementia is due to Alzheimer disease.