Alzheimer's Disease-Like Pattern of 18 F-FDG Uptake during a Hyperglycemic State and Negative 11 C-PiB Binding in a Patient with Mild Cognitive Impairment

Increased plasma glucose levels can cause the regional reduction of fluorine-18-labeled fluorodeoxyglucose (¹⁸F-FDG) uptake in the posterior cingulate, precuneus, and/or temporoparietal cortices as an Alzheimer's disease (AD)-like pattern. However, the association of such an AD-like pattern of cerebral ¹⁸F-FDG uptake with AD pathophysiology is unknown. We report a case of a 70-year-old patient with mild cognitive impairment, and show that the AD-like pattern of cerebral ¹⁸F-FDG uptake during a hyperglycemic state could be reversible and is not associated with amyloid-β accumulation. Our case concludes that the AD-like pattern is dependent on the plasma glucose level and independent of AD pathophysiology.