A simple, mechanical infusion pump that employs a constant force, nonf
erromagnetic spring to squeeze a syringe is described. The contrast in
fusion rate is determined by the spring force, gadolinium solution vis
cosity, and the resistance of either a user-selected needle or a preci
sion orifice according to Poiseuille's Law or the Bernoulli effect. It
s use in dynamic, gadolinium-enhanced 3D MR angiography is described.