Method for reducing frequency aliasing effect of undersampled magnetic resonance imaging

Abstract

The invention discloses a method for reducing a frequency aliasing effect of undersampled magnetic resonance imaging. The method comprises the following steps of (1) obtaining space K through a nuclear magnetic resonance spectrometer and performing undersampling on the original data of the space K by using a random oscillometric method to obtain undersampling data; (2) forming an over-complete dictionary by selecting a sparse method; and (3) performing recovery reestablishment on the undersampled data in the step (1) by using a recovery algorithm according to the over-complete dictionary to obtain original data, performing Fourier transform to obtain images and performing real-time imaging. The random oscillometric method comprises a variable-density oscillating spiral track and a variable-density oscillating radiation track.

Description

technical field [0001] The invention relates to a random oscillation method for nuclear magnetic resonance K-space undersampling, in particular to a method for reducing the frequency aliasing effect of undersampling magnetic resonance imaging based on the principle of compressed sensing. Background technique [0002] Long data acquisition time is the biggest disadvantage of magnetic resonance imaging technology. Due to the slow imaging speed, the scope of application of this examination is greatly reduced. For example, it is not suitable for the examination of sports organs and critically ill patients; It is also difficult to image without sedation; some applications in pediatrics are also limited. Shortening the imaging time can not only improve efficiency and patient comfort, reduce time-dependent artifacts, but also is the key to realize dynamic imaging such as cardiovascular examination, functional information acquisition, real-time temperature detection and intervention...

AI Technical Summary

Problems solved by technology

But this is a simple variable density algorithm, there will still be some aliasing artifacts in many places, and the effect of randomness is not obvious

[0004] Chinese patent application 201210390285X proposes a "magnetic resonance imaging sampling trajectory optimization method", although the method adopts different acquisition strategies in the low-frequency band and high-frequency band to optimize the sampling trajectory, and the optimization efficiency is high to ensure a high down-sampling factor and reconstructed image quality, but it is essentially a simple variable-density parallel K-space undersampling, and there is still room for improvement. At the same time, the modified method is only used in the parallel method and cannot be expanded.

Interference fringes will seriously affect the quality of MRI imaging, produce artifacts, and interfere with clinical diagnosis

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