The invention relates to a method of estimating a velocity of a contrast agent. The method comprises receiving a plurality of video frames that were produced using a dynamic contrast enhanced imaging process, each video frame comprising a plurality of pixels/voxels. Information from the video frames is used to estimate velocity vectors indicating the velocity and direction of the agent with the vascular networks. The estimated velocity can be used to diagnose cancer, such as prostate cancer. Instead of velocity vectors, agent trajectories can be determined also used for the same purpose.
