1. A method for processing an image of a body region, the region comprising a plurality of vessels capable of propagating a fluid of the body, the image comprising a plurality of pixels each being associated with an intensity , the method comprising: determining , for each pixel, a probability that the pixel belongs to a vessel, based on the intensity of the pixel; simulating a propagation of the fluid from at least one source pixel towards the pixels of the image, the propagation being simulated to have a velocity that is function of the probability that the pixels of the image belong to a vessel; and inferring from the simulation a propagation time between the source pixel and each of the pixels of the image.