Method and apparatus for correcting gradient system and static magnetic field in magnetic resonance imaging

摘要

Time-varying error between a prescribed magnetic field and an actual magnetic field is identified from a self-encoding technique and the measurement of detected responses to various magnetic read-out gradients. The gradients can be a sinusoidal, step function, or other suitable form which enables the actual responses to be obtained from which transfer functions can be defined. In one embodiment, the data can effectively frequency sample the transfer function of the system. A gradient-recalled echo occurs each time the self-encode lobe is refocussed, and the phase of the echo peak is used to estimate the time variation of the main magnetic field, B0(t).