The quantitative nature of phase contrast magnetic resonance angiography is explored, and a technique of blood flow measurement that is independent of system and patient parameters is presented. Phantom and patient studies demonstrate that quantitative flow measurements by phase contrast angiography can be routinely obtained with good accuracy despite nonuniform sensitivity profiles, blood flow pulsatility, and patient-to-patient changes in system gain. The calibration method requires the acquisition of only two flow images and thus can be performed as part of an angiographic session. Flow calibration of any flow profile can be accomplished with this technique. The solutions for plug flow and parabolic flow are presented.