Recent diagnostic criteria for Alzheimer's disease incorporate biomarkers in order to increase the diagnostic accuracy. In a recent Cochrane review the ligand (11)C-PiB showed a high sensitivity, but low specificity for detecting patients with mild cognitive impairment who would develop Alzheimer's dementia. Given the evolution of Alzheimer pathology, these findings are not surprising. With current limited treatment options for MCI, (11)C-PiB-PET cannot be recommended for routine use in MCI and should be used only in selected cases where a positive scan will alter management.