Alzheimer’s disease (AD) is the most common type of dementia that most often affects the elderly. The slow and irreversible progression of AD has devastating impact both financially and emotionally on the patients and their families. It is estimated that 4 million Americans are currently affected by AD and 14 million Americans will be affected by 2050. Early diagnosis of AD is critical both for the clinical treatment and for the families of the patients. However, lack of accurate and reliable means of diagnosis at the early stage of AD prevents the maximum use of treatments and services available to the Alzheimer's patient. In addition, being unable to diagnose AD early also restrictes the development of potential anti-AD drugs targeting the early stage of the disease. The current diagnosis of AD is mainly based on clinical symptoms and neuro-psychological examinations. Notably, the unique pathological features of AD may be detected by advanced neuroimaging technology, therefore allowing accurate diagnosis. Detecting brain damage may also allow for early diagnosis of AD, as it is believed that damage in two particular anatomic regions, entorhinal cortex and hippocampus, in the brain begin many years before the onset of symptoms of AD. Magnetization Transfer Ratio (MTR) is a medical imaging technology that is able to detect the type of brain damage associated with AD and therefore is a promising tool for early diagnosis. However, conventional MTR has many technical problems such as low spatial resolution and wide variability. Moreover, the particular brain regions where AD starts are very small structures that cannot be discerned by conventional MTR. So far, the use of MTR for diagnosis of AD has not been systematically investigated.Our laboratory is dedicated to developing neuropathological imaging techniques to detect brain injury. We have recently developed a High Resolution Magnetization Transfer Imaging (hq-MT) technique for probing brain injury in AD patients. This novel technique is designed specifically to discern small structures of the brain such as those that correspond to the brain damage in AD. The preliminary experiments using this technique have demonstrated quantifiable visualization of the particular regions of the entorhinal cortex and hippocampus where AD starts compared to the conventional MTR. In this study, we propose to recruit healthy human subjects to validate this technique for quantitative and qualitative analysis and at the same time generate "normative" data that will be used as reference for measurements in AD patients. The ultimate aim is to define damage to the entorhinal cortex and hippocampus and create new biomarkers. This novel technique, if validated, will establish a new diagnostic paradigm to guide the treatment of AD patients as well as the development of anti-AD drugs targeting at early stage of AD.