A Water-fat Separation and Reconstruction Method Based on Single-Scan Spatiotemporal Encoded Magnetic Resonance Imaging

Abstract

The invention provides a water-fat separation and rebuilding method based on single-scanning space-time coding magnetic resonance imaging, and relates to a magnetic resonance imaging method. The method comprises the steps of utilizing a single-scanning space-time coding and imaging sequence to encode and collect a water-fat signal, wherein a 90-degree linear frequency sweep pulse is combined with a space-time coding gradient to give one quadratic phase to the water-fat signal in an exciting stage; based on the characteristic, obtaining priori knowledge images of water and fat used for guiding water-fat separation and rebuilding by selecting an appropriate filter to preprocess collected data; in a water-fat separation stage, utilizing the priori knowledge images as an initial value and weighted information, and obtaining a high-resolution and high-signal-to-noise ratio water image and fat image by solving a super-resolution lifting and edge artifact removing algorithm equation in a water-fat environment. According to the water-fat separation and rebuilding method based on single-scanning space-time coding magnetic resonance imaging, the water-fat separation of single-scanning space-time coding magnetic resonance imaging can be effectively achieved, meanwhile the image quality of separated images is improved, and the clinical application progress is promoted.

Description

technical field [0001] The present invention relates to a magnetic resonance imaging (Magnetic Resonance Imaging, MRI) method, in particular to a water-fat separation reconstruction method based on single-scan spatio-temporal coding magnetic resonance imaging, which can effectively improve the image resolution of ultra-fast water-fat separation imaging and signal-to-noise ratio. Background technique [0002] The signals detected by magnetic resonance imaging techniques usually come from the signals generated by hydrogen protons in some molecules, such as water and lipids. For the most part, the signal from hydrogen protons in water is of interest for many practical applications. But because fat has a rather short T1 relaxation time, it will appear hyperintense in many important imaging sequences, such as fast spin echo sequences [1] , Spoiled gradient echo sequence [2,3] and the steady-state free precession sequence [4] . Such hyperintensities are very unfavorable for c...

AI Technical Summary

Problems solved by technology

[0003] At present, there are several relatively mature water-fat separation technologies, but they all have the following disadvantages: (1) Chemical shift selective (chemical shift selective, CHESS) fat-compression imaging technology [5,6] Easy to implement and compatible with most sequences, but for B 0 and B 1 Sensitive to field inhomogeneities, which can lead to inaccuracies in liposuction

(2) Spatial-spectral excitation technology [7,8] Directly aim at the water for excitation, which can improve the B 1 resistance to inhomogeneous fields, but is also susceptible to B 0 Effect of inhomogeneous field

The disadvantage is that this technique cannot be applied to T2-weighted imaging or proton density-weighted imaging, and there is some damage to the signal-to-noise ratio

However, since the number of unknowns of the equation to be solved is twice the number of equations, the resolution of the obtained water and fat images will be lost by half, so the super-resolution reconstruction algorithm is crucial for improving the image quality of water-fat separation. important [18-23]

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