1. A method of deriving blood perfusion indices for a region of interest (ROI) of a subject, the method comprising the steps of: administering a contrast agent to the subject during a dynamic imaging scan: converting signal intensity data from raw images of the scan into contrast agent concentration data; deriving parameters from the contrast agent concentration data using at least one transport function that accounts for delay and dispersion of the contrast agent; and calculating the blood perfusion indices from the derived parameters.