In this explorative longitudinal study 50 patients with Alzheimer's disease (AD) and 50 age-matched control subjects will be recruited for their 2 years follow-ups and undergo extensive cognitive testing and quantitative 3 Tesla magnetic resonance imaging (MRI). Regional differences of susceptibility and R2* relaxation rates in deep gray matter and the neocortex will be evaluated in AD patients and controls and related to the patients´ cognitive status at baseline.