Longitudinal Quantitative Susceptibility Mapping (QSM) in Alzheimer 's Disease

Abnormally increased brain iron accumulation in deep gray matter is a common finding in Alzheimer's disease (AD) and amyloid protein precursor and tau proteins were linked to disrupted iron homeostasis. Validation studies showed that brain iron can be measured precisely by the novel magnetic resonance imaging (MRI) technique quantitative susceptibility mapping (QSM) in vivo, thus, enabling reliable and precise longitudinal investigations. It is hypothesized that pathologic brain iron accumulation can be assessed with higher sensitivity with QSM than with current MRI techniques such as R2\* relaxation rate mapping and that regional QSM is a predictor for cognitive decline and disability. This explorative longitudinal study is including 50 patients with AD and age-matched control subjects which will be recruited for their 2 years follow-ups and undergo extensive cognitive testing and quantitative 3 Tesla MRI. Regional differences of susceptibility and R2\* in deep gray matter and the neocortex will be evaluated in AD patients and controls and related to the patients´ cognitive status at baseline. Follow-up MRI and clinical data with multivariate regression analysis serve to investigate the dynamics of AD-related changes of susceptibility, and their relation to cognitive functioning. In conclusion, this explorative longitudinal study in a patient cohort aims to clarify whether regional QSM changes are potential biomarkers for AD progression.