Patent ID: 8143887

Claim:
A method for measuring the flow velocity of at least one fluid of interest in a multi-phase fluid flowing in a pipe at a known overall flow rate, comprising the steps of: a) providing an MRI-compatible device comprising: a magnetic resonance module through which the fluid phases flow; and at least one pre-polarization module producing a pre-polarization magnetic field of variable effective length through which the multi-phase fluid flows before entering the magnetic resonance module; wherein a previously determined calibration, of the magnetic resonance module, between a slope:intercept ratio and the flow rate for a fluid of interest flowing through the device is known; b) conducting a measurement comprising the steps of: i) setting the pre-polarization module such that a first effective length of the pre-polarization magnetic field is produced; ii) applying a RF pulse sequence for measuring flow velocity of a fluid of interest in the magnetic resonance module; iii) determining the intensity of a pre-determined number of spin echoes that are produced by the RF pulse sequence; iv) determining a line that approximates the attenuation of the intensity of the pre-determined number of spin echoes with increasing time during which the RF sequence is applied; v) determining slope and y-intercept of the line determined in step iv); vi) determining the ratio of the slope and the intercept determined in step v); vii) applying the previously determined calibration in order to determine the flow velocity of the fluid of interest in the multi-phase fluid; and viii) providing the flow velocity determined in step b)vii) to a user; and c) when more than one fluid flow rate is desired is desired, repeating step b) one or more times, each time using a different setting of the pre-polarization module so as to determine the flow velocity of a different fluid of interest in the multi-phase fluid.