A method of predicting peak pressure within a fluid path, which includes a tubing set and a catheter into which at least one fluid is introduced under pressure by a pressurizing system of a fluid injection apparatus, includes (a) inputting an initial injection protocol into the fluid injection apparatus according to which the at least one fluid is intended to be introduced into the fluid path； (b) predicting an expected peak pressure level that would result in the fluid path if the initial injection protocol were to be used as intended to introduce the at least one fluid into the fluid path. The expected peak pressure level is determined before commencement of the initial injection protocol according to at least one model on the basis of a flow rate of the at least one fluid, at least one catheter characteristic, and a viscosity of the at least one fluid. The at least one model is determined experimentally for a plurality of fluids of different viscosities, for a plurality of catheters of different catheter characteristics, and for at least one tubing set of like kind to the tubing set of the fluid path.
