Patent ID: 6438404
Filing Date: 2002-08-20
Classification: G01R

Abstract:
A method of measuring a periodically varying fluid flow in an object by means of magnetic resonance, which object is arranged in a steady magnetic field, said method comprising:generating an excitation RF pulse in order to direct a reference magnetization into a transverse plane relative to the direction of the steady magnetic field, applying a first additional gradient in a flow direction of the fluid flow in order to produce a phase shift in the reference magnetization, generating a first additional RF pulse in order to direct the reference magnetization into the direction of the steady magnetic field, generating a second additional RF pulse in order to direct a part of the reference magnetization into a transverse direction relative to the direction of the steady magnetic field, applying a second additional gradient in the flow direction in order to cancel the phase shift caused by the first additional gradient in static material near the fluid flow, measuring a first MR signal, and determining a displacement of the fluid from the measured first MR signal and a reference MR signal, wherein, near a phase of a first period of the periodically a, varying fluid flow, the excitation RF pulse is generated, the first additional gradient is applied and the first additional RF pulse is generated, and, near a corresponding phase of a second period of the periodically varying fluid flow, the second additional RF pulse is generated, the second additional gradient is applied and the first MR signal is measured.