Dynamic multi-frequency electrical impedance tomography method based on impedance frequency spectrum constraint

A technology of electrical impedance tomography and impedance spectrum, applied in the directions of diagnosis, diagnostic recording/measurement, medical science, etc., can solve the problems of morbidity and poor image quality, and achieve the goal of improving the morbidity of inverse problems, strong noise suppression capability, and The effect of accurate location positioning

Active Publication Date: 2019-04-23
FOURTH MILITARY MEDICAL UNIVERSITY
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Problems solved by technology

[0005] Aiming at the inability to fundamentally improve the problems of morbidity and poor image quality in the prior art, the present invention provides a dynamic multi-frequency electrical impedance tomography method based on impedance spectrum constraints, including the following steps:

Method used

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  • Dynamic multi-frequency electrical impedance tomography method based on impedance frequency spectrum constraint
  • Dynamic multi-frequency electrical impedance tomography method based on impedance frequency spectrum constraint
  • Dynamic multi-frequency electrical impedance tomography method based on impedance frequency spectrum constraint

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Embodiment

[0087] When applying EIT to the brain, step 1: if Figure 2-Figure 5 As shown, first assume that there are T kinds of tissues in the three-dimensional area Ω, respectively: t 1 ... t j ... t T , (j and T are positive integers and j≤T) and obtain the impedance spectrum of this T tissue, and do finite element division of Ω, because the impedance in the surface element is continuous and consistent, the impedance vector σ i ∈R N*1 , where N is the subdivision panel number, i is the excitation frequency, R N*1 is a matrix of size N*1, and the volume fraction value of each tissue is set in each panel to obtain the volume fraction matrix FM∈R T*N , where R T*N is a matrix of size T*N, R T*NThe column of is the proportion of each tissue of surface element n, and n≤N, and the row is the proportion of tissue j in each surface element, and then vectorize FM by column to obtain the volume fraction vector F=vec(FM),F∈R (T*N)*1 ;

[0088] Step 2: Place 16 electrodes at equal interva...

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Abstract

The invention belongs to the field of electrical impedance tomography, and particularly relates to a dynamic multi-frequency electrical impedance tomography method based on the impedance frequency spectrum constraint. The method includes the steps that 1, limited surface element dividing is carried out in an imaging region, the variety number of tissue in the imaging region and the frequency spectrum of each kind of tissue are determined, and a relation model of the volume fraction and the boundary voltage is established; 2, the boundary of the imaging region is excited through exciting currents at different frequencies, and boundary voltage data at different moments at each frequency is measured; 3, an inverse problem objective function is established according to the relation of the volume fraction change and the boundary voltage pressure obtained in the step 1 and solved, and the change value of the volume fraction in the imaging region is obtained; 4, the volume fraction change isconverted into the impedance change, the impedance change is shown in the imaging region through color levels, and an impedance change image is obtained. A novel scheme for relieving the inverse problem morbidity is provided on the aspect of increasing the observation data size, and then the space resolution and the anti-noise capacity of the reconstructed image are improved.

Description

technical field [0001] The invention belongs to the field of electrical impedance tomography, in particular to a dynamic multi-frequency electrical impedance tomography method based on impedance spectrum constraints. Background technique [0002] Electrical impedance tomography technology regularly applies excitation current to the object through electrodes installed on the surface of the object. If there is an impedance change inside the object, it will cause a change in the voltage of the surface measurement electrode. Then, based on the finite element analysis, the forward problem model is established to obtain the corresponding relationship between the boundary voltage change and the impedance change in the imaging domain. Finally, the image of the internal impedance change of the object can be obtained according to the measured boundary voltage change combined with the corresponding reconstruction algorithm. In practical applications, serious ill-conditionedness is the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A61B5/053
CPCA61B5/0531A61B5/0536A61B5/7203
Inventor 曹璐杨滨付峰李昊庭史学涛季振宇刘本源夏军营周怡敏
Owner FOURTH MILITARY MEDICAL UNIVERSITY
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