Phase error detection method and device, magnetic resonance system and imaging method thereof

Abstract

The invention relates to a phase error detection method and device, a magnetic resonance system and an imaging method thereof. The phase error detection method comprises the steps of applying a first test sequence to a detection object to obtain the first phase information, wherein the first test sequence comprises a gradient module to be tested and a radio frequency pulse, the gradient module to be tested comprises at least two gradient units with opposite polarities, and a positive gradient unit is accompanied by the radio frequency pulse; applying a second test sequence to the detection object to obtain the second phase information, wherein the second test sequence comprises the gradient module to be tested and the radio frequency pulse, and a negative gradient unit is accompanied by the radio frequency pulse; and calculating a phase error corresponding to the gradient module to be tested according to the first phase information and the second phase information. The invention provides the novel phase error detection method which can accurately detect the eddy current phase errors.

Description

Technical field [0001] The present application relates to the magnetic resonance arts, and more particularly, to a method of error detection, apparatus, a magnetic resonance imaging system and a method of phase. Background technique [0002] The magnetic resonance imaging, gradient when the current changes (rising or falling), the gradient coils generate induced reverse current blocking this change, the formation of new magnetic field induced current, i.e., the eddy current. The presence of eddy currents, will significantly change the shape of the gradient current so as to have a greater impact on the image. [0003] Specifically, the gradient eddy current change generated in the process, results in additional error or phase of the magnetization vector summation linear gradient image artifacts. For example EPI (Echo Planar Imaging, echo planar imaging), the complete K-space acquisition, the read gradient is achieved by positive and negative variations and therefore odd and even a...

AI Technical Summary

Problems solved by technology

The existence of eddy currents will obviously change the shape of the gradient current, which will have a great impact on imaging

[0003] Specifically, the eddy current generated during the gradient current change will cause additional phase accumulation errors of the magnetization vector or gradient nonlinear image artifacts

For example, in EPI (Echo Planar Imaging, Echo Planar Imaging), in the complete K-space acquisition process, the reading gradient is realized through positive and negative changes, so the cumulative phases of odd and even lines are inconsistent, resulting in N / 2 artifacts in imaging; another example is 2D excitation RF pulse, when a certain direction of the excited K-space is a positive and negative round-trip gradient, there is a difference in the cumulative phase of the positive and negative gradient layer selection direction, resulting in N / 2 wrong excitation of the excitation; or UTE (ultra-short echo-time , ultra-short echo time) imaging, the deviation between the theoretical gradient and the actual gradient causes the offset of the K-space position, if no correction is made during reconstruction, there will be artifacts on the image, etc.

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