1. A method for assessing a treatment under trial, comprising: obtaining images generated from image data acquired at different times during a trial time period for a same anatomical region of a subject, wherein the treatment is administered to the subject for the trial; co-registering the images; mapping the co-registered images to a reference image representing the anatomical region; generating a trial image of the anatomical region showing at least one of structural or functional physiological changes that occurred during the trial time period based on the mapped co-registered images; and displaying the trial image.