1. A method for serially determining changes in perfusion to tissues, comprising the steps of: injecting contrast material into a catheter that is positioned in a blood vessel supplying a targeted tissue of interest; acquiring a time series of images that depicts an uptake of the contrast material within the targeted tissue; deriving semi-quantitative or quantitative perfusion metrics based upon the time series of images; altering perfusion to the targeted tissue by injecting pharmacologic agents or embolic agents into the blood vessel supplying the targeted tissue; acquiring a further time series of perfusion images to serially monitor changes in tissue perfusion after each altering perfusion step; repeating said altering perfusion step and said acquiring further images step; and calculating changes in perfusion metrics after said acquiring of the further series of perfusion images.