Blood Flow Measurements Using Dynamical Paramagnetic Relaxation Times and Paramagnetic Tracer Techniques

The effect of flow on the paramagnetic relaxation time of fluids is discussed. The saturation or magnetization inversion of a group of nuclear moments constitutes a short-lived tracer for these moments permitting flow velocity measurements. For long-lived tracers, a given set of molecules with a well-known nuclear or electron paramagnetic resonance spectrum may be employed. Experimental measures of blood flow velocity in mice are discussed.