Alzheimer's disease: Neuropathologic findings and recent advances in imaging

Whereas the histologic changes that underlie Alzheimer's disease have been known for approximately 100 years, the physiologic principles and genetic mechanisms governing formation of senile plaques and neurofibrillary tangles continue to be elucidated. During the past decade, neuroradiologists have moved beyond solely structural imaging techniques that assess volume loss in Alzheimer's disease. At present, physiologic imaging techniques, such as PET, MR hemodynamic imaging, and MR spectroscopy, are being coupled with ever more sensitive volumetric techniques for the assessment of Alzheimer's disease. The sensitivity and specificity profiles of these techniques will be better assessed in coming years, and methods to apply study findings to individual patients will need to be developed. These techniques will likely be increasingly used to improve the accuracy of diagnosis of Alzheimer's disease, identify patients at risk for developing Alzheimer's disease, and monitor the various therapeutic agents that are being developed to retard the progression of the disease.