Method for magnetic resonance angiography using in-flow of transverse spin magnetization

A method for the generation of magnetic resonance angiograms of a moving fluid within a subject, comprising the steps of:

• a) placing said subject into a magnetic field to polarize nuclear spins;
• b) applying to said subject an excitation radiofrequency (RF) pulse to nutate nuclear spins within said subject for the purpose of creating transverse spin magnetization;
• c) applying to said subject an excitation magnetic field gradient pulse substantially simultaneously with the application of the excitation RF pulse to constrain the creation of transverse spin magnetization to a selected portion of an excitation region within said subject including said moving fluid;
• d) applying to said subject after the application of the excitation RF pulse, a refocusing RF pulse subsequence to maintain coherence of the created transverse spin magnetization in said moving fluid as it moves from the excitation region to an acquisition region;
• e) applying to said subject after the application of the excitation RF pulse, a readout dephasing magnetic field gradient pulse of a selected amplitude in a first selected direction to cause transverse spin magnetization to be dephased by an amount proportional to the location of the transverse magnetization in the first direction;
• f) applying a readout magnetic field gradient pulse in the first selected direction with a polarity substantially opposite that of the readout dephasing magnetic field gradient pulse;
• g) detecting with a receiver operating at a selected frequency, an MR response signal generated by the transverse spin magnetization of the acquisition region in the presence of the readout magnetic field gradient pulse;
• h) repeating steps `b`-`g` a plurality of Y repetitions;
• and
• i) creating a reconstructed MR image of a region different from the excitation region, from the acquired MR response signals.