A method for determining a tissue parameter of tissue that may be determined from passage of a contrast agent through the tissue based on a series of temporally consecutive two-dimensional digital subtraction angiography x-ray images showing propagation of the contrast agent in the tissue over time and a vascular system present in a region of the tissue includes locating at least some of the vessels of the vascular system by segmentation in the x-ray images. The method also includes assigning pixels showing segmented vessels an interpolation intensity determined by interpolation from intensities of at least some of the pixels bordering the segmented vessel, so that x-ray images from which vessels have been eliminated result. The method includes determining tissue parameters for at least some of the pixels of the series of x-ray images from which the vessels have been eliminated.
