1. A process for producing a magnetic resonance image of a region of fluid flow, comprising the steps of: generating a first set of signals representing a first magnetic resonance image of said region of fluid flow; generating a second set of signals representing a second magnetic resonance image of said region of fluid flow such that signal intensities of said second set of signals for said region of fluid flow differ from signal intensities of said first set of signals for said region of fluid flow; comparing said first set of signals to a first threshold level to distinguish static material from fluid flow; comparing said second set of signals to a second threshold level to distinguish static material from fluid flow; logically differentiating said first set of signals from said second set of signals by differentiating protons in said fluid flow from other protons; and producing an image of said region of fluid flow from said logically differentiating step; wherein said step of producing said image comprises the step of displaying portions of said region as having fluid flow when signals in said second set of signals for the portions are below said second threshold level but signals in said first set of signals for said portions are above said first threshold.