A method for determining a four-dimensional angiography dataset describing the flow of contrast agent over time through a blood vessel system of the body of a patient is provided. Four-dimensional flow information is obtained from two-dimensional images captured in a capture time period in different projection directions using a biplanar x-ray device in an inflow phase and/or an outflow phase of the contrast agent by back projection of the images. A three-dimensional reconstruction dataset is determined from the projection of the images depending on the flow information during a filling phase in which the contrast agent is present evenly distributed in the blood vessel system. The three-dimensional reconstruction dataset is animated in order to determine the angiography dataset. The capture time periods for the inflow phase and/or the outflow phase are determined from images captured of a test bolus.
