1. A method for reconstructing an image of an object from image data, comprising: a processor receiving non-contrast-enhanced magnetic resonance image data of the object containing a first and a second dataset in k-space obtained with a medical imaging device which are acquired in an undersampled manner, wherein the first and second dataset in k-space are steady-state free precession (SSFP) repetition acquisitions of one phase of multiple phases in a cine angiography; the processor generating a sparsified third dataset prior to image reconstruction by creating a difference set in k-space by subtracting the first from the second dataset in k-space and by applying a Karhunen-Loeve Transform (KLT) over a temporal dimension of an inverse Fourier Transform of the difference set; and the processor iteratively minimizing an objective function under a constraint related to the sparsified third dataset to reconstruct the image of the object, wherein one or more artifacts due to the acquisition in the undersampled manner are suppressed.