1. A method for generating an at least three-dimensional display data set of a plurality of time parameters relating to chronological spreading of a contrast medium introduced into a vessel system from a series of chronologically successive x-ray images of digital subtraction angiography from at least two different projection directions showing the chronological spreading of the contrast medium, the method comprising: determining a plurality of three-dimensional positions, each of the three-dimensional positions based on at least two correspondence points defined in different projection directions of digital subtraction angiography images, the at least two correspondence points for each different three-dimensional position marking the same vessel in the different projection directions of digital subtraction angiography images; determining the plurality of time parameters, wherein each time parameter is determined for a different one of the plurality of three-dimensional positions, the determining of each of the plurality of time parameters comprising: evaluating time-intensity curves for the at least two correspondence points to derive individual time parameters for different projection directions; and combining the individual time parameters for different projection directions to derive one of the plurality time parameters for one of the plurality of three-dimensional positions; displaying the at least three-dimensional display data set formed from the plurality of three-dimensional positions and the plurality of time parameters determined for each of the plurality of three-dimensional positions.