Theoretical sensitivity of perivascular electromagnetic flowmeters deduced from the distribution of an applied inter-electrode potential.

A hypothetical electromagnetic blood flowmeter is considered in which the electrode system and the magnetic field are invariant in the direction of flow. If a voltage from an external source is applied between the electrodes, a potential distribution is produced on the outside of the vessel. It is shown that the sensitivity of the flowmeter to axisymmetric flow can theoretically be deduced from the potential distribution provided the vessel and blood have uniform, isotropic conductivities. The method, if applicable to practical flowmeters, would permit in vivo monitoring of flowmeter sensitivity.