Methods and compositions are provided for objectively characterizing a pathological lesion in a patient. The method comprises: introducing into the patient a contrast enhancing agent； subjecting the patient to at least one of magnetic resonance imaging and computed tomography to obtain an image； and applying a 3-D autocorrelation function to a subdomain of interest of the image to obtain at least one 3-D autocorrelation spectrum. The method may further comprise comparing the at least one 3-D autocorrelation spectrum to a pre-existing 3-D autocorrelation spectrum that is characteristic for the pathological lesion. In one example, the methods and compositions may be useful for identifying and objectively characterizing amyloid plaque deposits characteristic of Alzheimer's Disease.
