To improve the clinical detection of Alzheimer's disease (AD) new diagnostic criteria have been proposed, based on biomarkers of synaptic dysfunction, AD-related neurodegeneration, and Aβ cerebral amyloidosis. Magnetic resonance imaging (MRI) and position emission tomography (PET) neuroimaging can be configured as powerful means for the detection of medial-temporal atrophy, reduced uptake of 18F-FDG PET or and increased retention of Aβ amyloid protein by amyloïd-PET. In this review, we will discuss these promising techniques that allow assessing in vivo AD pathology and help clinicians to better diagnose and follow-up patients, particularly in clinical trials using disease-modifying treatments.