1. A method of controlling an injector system for delivering a contrast enhancing fluid to a patient, comprising: (a) determining at least one patient transfer function for the patient based upon data specific to the patient, the at least one patient transfer function providing a time enhancement output for a given input, the data specific to the patient including at least one of an estimate of physiological parameters of the patient, an estimate of anatomic parameters of the patient and an enhancement caused by an injection of the contrast enhancing fluid into the patient; (b) determining a desired time enhancement output; (c) using the at least one patient transfer function to determine an injection procedure input; and (d) controlling the injector system at least in part on the basis of the determined injection procedure input.