A method to reduce frequency aliasing effects in undersampled magnetic resonance imaging

A magnetic resonance imaging and undersampling technology, which is applied in the direction of using nuclear magnetic resonance imaging system for measurement, magnetic resonance measurement, and magnetic variable measurement, etc., can solve the problem of affecting the quality of MRI imaging, not having more expansion, and generating artifacts, etc. question

Active Publication Date: 2017-06-16
NANJING MEDICAL UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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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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  • A method to reduce frequency aliasing effects in undersampled magnetic resonance imaging
  • A method to reduce frequency aliasing effects in undersampled magnetic resonance imaging
  • A method to reduce frequency aliasing effects in undersampled magnetic resonance imaging

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Embodiment 1

[0054] Take the helical random oscillation as an example of the application of the present invention in head MR imaging:

[0055] Measurement purpose: Imaging the head, whether the effect is better than other methods, and whether there are aliasing artifacts.

[0056] Measuring device: nuclear magnetic resonance instrument, computer

[0057] Measuring samples: NMR room of Jiangsu Provincial People's Hospital

[0058] Measuring method: the specific steps that the present invention is applied to head MR imaging include as follows:

[0059] Step 1: Obtain the K-space through the nuclear magnetic resonance instrument, and design a trajectory for undersampling the K-space, and use the random oscillation method to undersample the original K-space with the spiral trajectory of variable density oscillation.

[0060] For the spirally undersampled trajectory r i (θ i ) 1 , the construction method in the polar coordinate system is as follows, and then transferred to Cartesian coordi...

Embodiment 2

[0081] Embodiment 2, taking the application of the present invention to take radiation random oscillation as an example to apply to head MR imaging:

[0082] Measurement purpose: Imaging the head, whether the effect is better than other methods, and whether there are aliasing artifacts.

[0083] Measuring device: nuclear magnetic resonance instrument, computer

[0084] Measuring samples: NMR room of Jiangsu Provincial People's Hospital

[0085] Measuring method: the specific steps that the present invention is applied to measuring head MR imaging include as follows:

[0086] Step 1: Obtain the K-space by nuclear magnetic resonance, and design a trajectory for undersampling the K-space, and use the random oscillation method to undersample the original K-space with the radiation trajectory of variable density oscillation.

[0087] Generating radial trajectories of variable density oscillations

[0088]

[0089]

[0090] in r∈[-R,R], corresponding to the radially und...

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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...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R33/56
Inventor 王伟阮俊张可张作恒吴小玲朱松盛段磊刘宾陶健
Owner NANJING MEDICAL UNIV
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