1. A method for reconstructing a series of images of a subject with a medical imaging system, the steps of the method comprising: a) acquiring medical image data from the subject with a medical imaging system; and b) reconstructing a series of images of the subject from the acquired medical image data set while constraining individual images in the series of images to be consistent with a signal model that describes a dependency of image intensity values to at least one variable that is associated with a physical property of the subject.