Magnetoacoustic tomography with magnetic induction (MAT-MI)

Xu, Yuan; He, Bin

doi:10.1088/0031-9155/50/21/015

Cited by 201 publications

(238 citation statements)

References 32 publications

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“…As a consequence, the overall tomography system sensitivity to the changes of the object's conductivity will be decreased. Such a phenomenon is commonly called the shielding effect [7]. In order to avoid this problem magnetic induction tomography MIT has been developed, where the eddy currents are generated in the object due to the use of magnetic induction [8].…”

Section: Fundamentals Of Mat-mi Theorymentioning

confidence: 99%

“…Propagated acoustic waves can be acquired by a set of piezoelectric transducers located around the object. Collected signals are then used for electrical conductivity image reconstruction, which leads to well-posed imaging inverse problem [7]. The illustration of the MAT-MI concept has been shown in Figure 1.…”

Section: Fundamentals Of Mat-mi Theorymentioning

confidence: 99%

“…Assuming that the magnetic field stimulation pulse is short enough, after separating the spatial and temporal functions of the time-varying magnetic fields, the Lorentz force density acting on eddy currents over unit volume can be written as [4,7,8]:…”

Section: Forward Problem Formulationmentioning

confidence: 99%

“…The force resulting from Equation (2) leads to mechanical vibrations and generates an acoustic wave governed by the following wave Equation [7,9]:…”

Section: Forward Problem Formulationmentioning

confidence: 99%

“…It should be noted, that in this case J(r) has the unit of A·s/m 2 and based on this assumption the next equations are constructed [7].…”

Section: Forward Problem Formulationmentioning

confidence: 99%

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Magnetoacoustic tomography with magnetic induction for biological tissue imaging: numerical modelling and simulations

Zywica

2016

Archives of Electrical Engineering

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Many imaging techniques are playing an increasingly significant role in clinical diagnosis. In the last years especially noninvasive electrical conductivity imaging methods have been investigated. Magnetoacoustic tomography with magnetic induction (MAT-MI) combines favourable contrast of electromagnetic tomography with good spatial resolution of sonography. In this paper a finite element model of MAT-MI forward problem has been presented. The reconstruction of the Lorentz force distribution has been performed with the help of a time reversal algorithm.

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Section: Fundamentals Of Mat-mi Theorymentioning

confidence: 99%

Section: Fundamentals Of Mat-mi Theorymentioning

confidence: 99%

Section: Forward Problem Formulationmentioning

confidence: 99%

“…The force resulting from Equation (2) leads to mechanical vibrations and generates an acoustic wave governed by the following wave Equation [7,9]:…”

Section: Forward Problem Formulationmentioning

confidence: 99%

“…It should be noted, that in this case J(r) has the unit of A·s/m 2 and based on this assumption the next equations are constructed [7].…”

Section: Forward Problem Formulationmentioning

confidence: 99%

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Magnetoacoustic tomography with magnetic induction for biological tissue imaging: numerical modelling and simulations

Zywica

2016

Archives of Electrical Engineering

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Computational method for estimating boundary of abdominal subcutaneous fat for absolute electrical impedance tomography

Yamaguchi

Okamoto

2017

Numer Methods Biomed Eng

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Abdominal fat accumulation is considered an essential indicator of human health. Electrical impedance tomography has considerable potential for abdominal fat imaging because of the low specific conductivity of human body fat. In this paper, we propose a robust reconstruction method for high-fidelity conductivity imaging by abstraction of the abdominal cross section using a relatively small number of parameters. Toward this end, we assume homogeneous conductivity in the abdominal subcutaneous fat area and characterize its geometrical shape by parameters defined as the ratio of the distance from the center to boundary of subcutaneous fat to the distance from the center to outer boundary in 64 equiangular directions. To estimate the shape parameters, the sensitivity of the noninvasively measured voltages with respect to the shape parameters is formulated for numerical optimization. Numerical simulations are conducted to demonstrate the validity of the proposed method. A 3-dimensional finite element method is used to construct a computer model of the human abdomen. The inverse problems of shape parameters and conductivities are solved concurrently by iterative forward and inverse calculations. As a result, conductivity images are reconstructed with a small systemic error of less than 1% for the estimation of the subcutaneous fat area. A novel method is devised for estimating the boundary of the abdominal subcutaneous fat. The fidelity of the overall reconstructed image to the reference image is significantly improved. The results demonstrate the possibility of realization of an abdominal fat scanner as a low-cost, radiation-free medical device.

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Novel reconstruction algorithm of magnetoacoustic tomography based on ring transducer array for acoustic speed inhomogeneous tissues

Wang

Liu

Chen³

et al. 2020

Medical Physics

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Purpose Magnetoacoustic tomography with magnetic induction (MAT‐MI) is a technique that utilizes the acoustic signals induced by magnetic stimulation to reconstruct the electrical impedance distribution in biological tissues. Most algorithms ignored the fact that acoustic properties in human tissues are heterogeneous, which lead to distortion and blurring of small reconstructed objects. In this study, a novel algorithm is proposed for exact reconstruction of the sound source distribution in acoustic heterogeneous tissues. Methods Based on the ring transducer array, we develop an algorithm which combines algebraic reconstruction technique (ART) and time reversal method. Different to existing reconstruction methods, the ultrasonic transmission tomography (UTT) and the MAT‐MI can be completed in same system, which decreases the system complexity. The sound velocity distribution is reconstructed with the ART so that the propagation time of the magnetoacoustic signals in the heterogeneous tissue is corrected. And then, the sound source image is reconstructed based on the time reversal method from new sound pressure data. Both numerical simulations and phantom experiments are established to validate the proposed method. Results Compared with the results without consideration of the variation on acoustic speed, sound sources reconstructed by our method are more consistent with the model in terms of size and shape. Conclusions The novel algorithm can be used to reconstruct the high‐accuracy image of MAT‐MI sound source in the sound velocity inhomogeneous media. In addition, this method is applicable to scenarios that the prior knowledge of the imaging targets is unknown. The signal acquisition time of MAT‐MI in acoustically heterogeneity media is greatly reduced due to the introduction of ring transducer array into the imaging system. Therefore, our method will promote the application of MAT‐MI in noninvasive early diagnosis of tumor for preclinical study.

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Magnetoacoustic tomography with magnetic induction (MAT-MI)

Cited by 201 publications

References 32 publications

Magnetoacoustic tomography with magnetic induction for biological tissue imaging: numerical modelling and simulations

Magnetoacoustic tomography with magnetic induction for biological tissue imaging: numerical modelling and simulations

Computational method for estimating boundary of abdominal subcutaneous fat for absolute electrical impedance tomography

Novel reconstruction algorithm of magnetoacoustic tomography based on ring transducer array for acoustic speed inhomogeneous tissues

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