1. A method of economizing a Magnetic Resonance Imaging (MRI) protocol using an MRI apparatus, the method comprising the steps of: collecting a plurality of prior MRI image scan data sets for a subject; obtaining a current MRI image scan data set for the subject; and reconstructing the current MRI image scan data set using an aggregate of the plurality of prior MRI image data sets, wherein the reconstructing step includes a step of estimating correlation functions by ensemble summation of the plurality of prior MRI image scan data sets.