Sampling-ring saturation pulse for two-dimensional magnetic resonance selective excitation

A method of magnetic resonance (MR) imaging of a region of a subject while suppressing ring artifacts, comprising the steps of:

• a) defining a target annular region which covers ring artifacts, and excludes a central region;
• b) calculating a pair of time-varying magnetic field gradient waveforms g.sub.x (t), g.sub.y (t) along an "X" and "Y" axis respectively that, when applied with a predetermined radiofrequency (RF) pulse to the subject, will excite magnetization of the target annular region of the subject;
• c) calculating a time-varying RF pulse b.sub.1 (t) that when applied to the subject with time-varying magnetic field gradient waveforms g.sub.x (t), g.sub.y (t) will excite magnetization of the target annular region of the subject;
• e) simultaneously applying the magnetic field gradient waveforms g.sub.x (t), g.sub.y (t) and the RF pulse b.sub.1 (t) to the subject to excite magnetization of the target annular region of the subject;
• f) subsequently applying `crusher` gradient pulses to dephase the excited magnetization in the annular region;
• g) applying a two-dimensional (2D) MR excitation pulse to said region to be imaged;
• h) receiving an MR response signal from the region to be imaged such that relatively little signal is contributed from the target annular region of said subject;
• and
• i) reconstructing an image of the region to be imaged having minimal sampling-ring artifacts from the MR response signal.