1. A system for processing medical images of human tissue under study comprising: a first memory storing a plurality of sets of images of locations representative of tissue with a patient under study; a first set of said plurality of the sets of images representing tissue prior to injection of a contrast agent; a second set of said plurality of the sets of images representing tissue at a selected time after injection of a contrast agent; a second memory storing a plurality of rules to be applied to said images; and a visual display having an image from said plurality of sets of images displayed thereon, the image having an indicia thereon of those pixels within the image that fall with the rules stored on the second memory.