Structural and functional neuroimaging in Alzheimer's disease: an update.

The field of neuroimaging has made several recent advances understanding Alzheimer's disease, a debilitating disease which affects approximately 4 million people in the United States [1]. Despite recent therapeutic advances, available treatments at present are aimed primarily at slowing progression of the disease rather than halting it completely or reversing its progression. Early detection of the disease has, therefore, been a major focus of a variety of neuroimaging techniques, including Positron Emission Tomography (PET), functional Magnetic Resonance Imaging (fMRI), and structural MRI. Recently, these techniques have also been found to be useful in monitoring cognitive and pathological progression of the disease, as well as monitoring response to clinical intervention treatment. A methodology review will be included here as well as a critical evaluation of the advantages and disadvantages of the various techniques.