An input image includes a plurality of input values (i.e., pixel or voxel values), each input value indicative of a response to an interrogation signal of a corresponding location of a body-part, which possibly includes a contrast agent. At least one filtered image is generated from a plurality of selected input images and includes a filtered value for each of a plurality of selected ones of the locations. Each filtered value is indicative of the contrast agent leaving the selected location and is obtained by reducing a contribution of the contrast agent that is substantially stationary at the selected location along the selected input images for a period of time equal to or shorter than a first threshold and by reducing a contribution of the contrast agent that is substantially stationary for a period of time equal to or longer than a second higher threshold.
