1. A method for reconstructing an image using a medical imaging system, the steps of the method comprising: (a) acquiring data from a subject with the imaging system; (b) initializing an image matrix having columns that each correspond to a different image of the subject that is consistent with at least a subset of the acquired data; (c) generating an augmented image matrix by augmenting the image matrix with a prior image that depicts the subject by vectorizing the prior image and concatenating the vectorized prior image as a column in the image matrix; (d) reconstructing at least one image of the subject from the data acquired in step (a) by: (i) performing a rank minimization to minimize a matrix rank of the augmented image matrix; and (ii) constraining the rank minimization of step (d)(i) subject to a consistency condition that promotes a forward projection of each column in the augmented image matrix to be consistent with a different subset of the acquired data, wherein each subset of the acquired data contains data that are consistent only with other data in that subset and are otherwise inconsistent with data in the other subsets of the acquired data; wherein step (a) includes acquiring contrast-enhanced data from the subject using a cone beam computed tomography imaging system, and wherein the data are acquired over a short scan.