Correcting method and correcting system for elastic rebuilding of magnetic resonance elastography (MRE)

Abstract

The invention relates to a correcting method and correcting system for elastic rebuilding of magnetic resonance elastography (MRE). The method comprises the following steps: acquiring a shear wave generated by an imaging object; comparing the size of the imaging object with the wavelength of the shear wave, and when the size of the imaging object and the wavelength of the shear wave are of an identical order of magnitude, the shear wave is introduced into a higher order term to correct an equation of motion and then obtain an objective function through calculation, wherein according to the objective function, gamma is the correction factor, mu is the lame constant, rho is the medium density, omega is the angular frequency of an incentive, and U is the displacement vector of a medium. According to the correcting method and correcting system for the elastic rebuilding of the MRE, through acquisition of the shear wave generated by the imaging object, comparison of the wavelength of the shear wave with the size of the imaging object and then adoption of an algorithm of the objective function, the elastic rebuilding can be relatively accurately achieved.

Description

Technical field [0001] The invention relates to a magnetic resonance elastography (Magnetic Resonance Elastography, MRE) technology, in particular to a method and system for elastic reconstruction and correction of magnetic resonance elastography. Background technique [0002] The elastic reconstruction algorithm is the most important part of the magnetic resonance elastography (MRE) process, which determines the spatial resolution and elasticity measurement accuracy of the MRE image. [0003] At present, the research of MRE elastic reconstruction algorithm mainly focuses on solving the Helmholtz algorithm. Assuming that the shear wave propagates in an isotropic infinite medium, and the influence of the longitudinal wave is ignored, the particle motion satisfies the Helmholtz equation Where U is the particle displacement, ρ is the medium density, ω is the angular frequency of the excitation, and μ shear modulus. [0004] At the same time, there are some other methods, such as local...

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Problems solved by technology

[0004] At the same time, there are some other methods, such as local frequency estimation (local frequency estimation, LFE), direct inversion method (Directly Inversion, DI), matched filter method (Matched Filter, MF), phase gradient method (Phase Gradient, PG) ), finite element iterative method (FEM), etc. However, there is a problem in the above-mentioned MRE elastic reconstruction algorithm: the algorithm assumes that the shear wave propagates in the infinite medium

But in fact, due to the influence of the boundary, the shear wave is reflected and refracted, and what MRE captures is the result of the superposition of multiple waves including reflected waves and reflected waves, which is contrary to the assumption, especially when the imaging object When the spatial dimension is close to or smaller than the shear wave wavelength, the elastic value calculated by the LFE, DI and PG methods will be significantly smaller than the actual value, and there is an error

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