A method of delivering a contrast enhancing fluid to a patient using an 
injector system, including: determining at least one 
patient transfer function for the patient based upon data specific to the patient and, the at least one 
patient transfer function providing a time enhancement output for a given input; determining a desired time enhancement output; using the at least one 
patient transfer function to determine an 
injection procedure input; and controlling the 
injector system at least in part on the basis of the determined 
injection procedure input. The 
injection procedure input can determined considering at least one operational limitation or constraint of the 
injector system. A method of modeling propagation of a pharmaceutical fluid in a patient, includes: collecting data corresponding to a 
time response curve resulting from injection of the fluid; and determining at least one 
mathematical model describing the data. The 
mathematical model can, for example, be a model which is not determined by a continuous or a discrete-time Fourier 
deconvolution of the data. A method of controlling injection of a pharmaceutical fluid into a patient using an injector in a 
medical procedure, includes: collecting data corresponding to a 
patient response curve resulting from injection of the fluid; determining at least one 
mathematical model describing the data; and controlling the injector during the 
medical procedure to control injection of the fluid into the patient to create 
patient response at least in part on the basis of the mathematical model. A method of controlling injection of a 
contrast medium into a patient using an injector in a 
medical imaging procedure using an imaging 
scanner, includes: determining at least one mathematical model to predict a time enhancement response resulting from injection of the 
contrast medium; determining an injection protocol to approximate a predetermined time enhancement response in the patient by determining a constrained input solution to the mathematical model; and using the injection protocol to control the injector during the 
medical imaging procedure to control injection of the 
contrast medium into the patient to create an image of a 
region of interest. 
Patient transfer functions for the patient of the present invention can also be based at least in part on a measurement of 
cardiac output of the patient. Likewise, mathematical models of the present invention can be based at least in part on a measurement of 
cardiac output of the patient.