1. A method of determining at least one parameter for an injection procedure to be performed in combination with an imaging procedure, the method comprising the steps of: (a) injecting a test bolus of a contrast enhancement fluid having a contrast enhancing agent therein; (b) scanning at least two regions of interest with an imaging system as the test bolus of the contrast enhancement fluid flows therethrough to obtain therefrom a contrast time enhancement curve for each of the at least two regions of interest; (c) extracting at least one discrete data point from each of the contrast time enhancement curves such that each of the discrete data points constitutes a pair of measurements on the contrast time enhancement curve corresponding thereto; (d) substituting into a model the discrete data points extracted from the contrast time enhancement curves to obtain therefrom at least an estimate of values of physiological variables; and (e) using the at least an estimate of the values of the physiological variables to determine via the model the at least one parameter for the injection procedure to be performed in combination with the imaging procedure.