1. A method of imaging the blood flow as a function of time in an object ( 3 ) to be examined, which method includes the following steps: a) acquisition of a series of X-ray projection images (D i ; E j ) during administration of a contrast medium to the blood vessels in the object ( 3 ) to be examined, b) acquisition of an image data set (H; K) containing the course of the blood vessels in the object ( 3 ) to be examined, c) segmentation of the regions of the blood vessels in the individual X-ray projection images (D i ; E j ) that are filled with contrast medium, d) encoding the image data set (H; K) in time by comparing the image data set (H; K) with the segmented X-ray projection images (D j ′; F j ), and e) displaying one or more images (B) formed from the time-encoded image data set (H′; R′) and representing the blood flow as a function of time.