Image Reconstruction in Magnetoacoustic Tomography With Magnetic Induction With Variable Sound Speeds

Zhang, Wei; Ma, Ren; Zhang, Shunqi; Yin, Tao; Liu, Zhipeng

doi:10.1109/tbme.2016.2602850

Cited by 12 publications

(12 citation statements)

References 32 publications

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“…To the best of our knowledge, some scholars have improved the MAT-MI reconstruction algorithm to make it applicable to acoustically inhomogeneous media. 22,25 The process of the reconstruction method can be divided into steps, which contains sound speed and acoustic sources reconstruction. To solve the forward problem, the pressure wave equation of MAT-MI was established based on the theoretical analysis, and then, the equation was solved to obtain the induced current and sound pressure in imaged sample, which was calculated by finite element method (FEM).…”

Section: Discussionmentioning

confidence: 99%

“…This calculation method can eliminate the artifacts which are generated due to low performance of the finite difference time domain (FDTD) method in curved structure. 25 To solve the inverse problem, we ignore the complex reflections and refractions during sound wave propagation and assume that ultrasound wave travels in a straight line. We used UTT to acquire the measurements, and then, the distribution of acoustic speed is reconstructed with ART.…”

Section: Discussionmentioning

confidence: 99%

“…Sharp 24 . This method is applicable for the tested tissues which are much smaller than the scanning radius of the transducer 25 . Zhang et al proposed a heuristic method for reconstructing both the acoustic speed and electromagnetic absorption distributions of a weakly scattering object in photoacoustic tomography, but this way requires prior knowledge of sound velocity distribution, which is difficult to achieve in practice 26 .…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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“…For a more accurate reconstruction, the reconstruction algorithms focused on real conditions of the MAT-MI system were developed. Such as beam-forming algorithm [8], the effects of acoustic heterogeneity [9] and the ultrasound transducer characteristics [10] were all considered into the reconstruction algorithms of MAT-MI. All the models above didn't show the direct relationship between ultrasound signals and the distribution of the conductivity.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Singular Values for Conductivity Reconstruction in Magneto-Acoustic Tomography With Magnetic Induction

Yang

Zhang

et al. 2020

IEEE Access

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Due to the acoustic source distribution and limited bandwidth ultrasound measurement, the dominant ultrasound signals always come from the boundary of the electrical conductivity in magneto-acoustic tomography with magnetic induction (MAT-MI). To make full use of the strong boundary ultrasound signals, a system matrix is built which shows the relationship between the electrical conductivity and the ultrasound signals. By analyzing the singular values of the system matrix, the necessary signal to noise ratio(SNR) level is estimated in this study. An inverse procedure based on the truncated singular value decomposition(TSVD) method is presented to improve the quality of the reconstructed MAT-MI image. Simulation results show that the reconstructed conductivity images by using the new algorithm match better than that of the back-projection algorithm. Both the simulation results and the experiment results prove the reconstructed image is close to the original conductivity distribution when the more singular values are used in the inverse procedure. Meanwhile, as the number of singular values increases, the effect of noise will be enhanced in the reconstructed image. The proposed reconstruction algorithm can improve the quality of the reconstruction image for a low SNR system. Moreover, the system matrix based reconstruction algorithm proposed in this work will help to analyze the physical process and to obtain accurate high-resolution reconstructions for MAT-MI. INDEX TERMS Magneto acoustic tomography with magnetic induction, singular values decomposition, system matrix, inverse problem, electrical conductivity.

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“…The method offers a potential solution to perform MAT-MI high-resolution imaging in acoustically inhomogeneous tissue, especially for brain imaging. In 2016, Wei Zhang et al analyzed the image reconstruction in magnetoacoustic tomography with magnetic induction with variable sound speeds provide a new algorithm to solve the forward and inverse problems in inhomogeneously acoustical media [5] . The solution of inverse problem can accurately reconstruct the distribution of acoustic sources in MAT-MI.…”

Section: Introductionmentioning

confidence: 99%

Study on the Influence of Acoustically Inhomogeneous Characteristics on Magneto-acoustic-electrical Tomography

Yan¹,

Zhang²,

Liu³

et al. 2018

dtcse

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Abstract. Magneto-acoustic-electrical tomography (MAET) is a method of non-invasive conductivity imaging, with three couplings of magnetic field, acoustic field and electric field. It is suitable for the conductivity imaging of low-conductivity fluid or approximate fluid medium. MAET will have a broad application prospect in the field of bio-impedance imaging. Acoustic and electrical characteristics of biological tissue are important factors in magneto-acoustic-electrical tomography, it is essential to evaluate the effect of acoustic inhomogeneity on the sound pressure distribution and the electrical signal. In this paper, a numerical analysis of the positive problem of magneto-acoustic -electrical tomography of eight groups of human tissues with different density and sound velocity, such as blood and cerebrospinal fluid, is carried out. Firstly, establishing a two-dimensional plane model of pure fluid and applying ultrasonic excitation. Secondly, combining with the current continuity theorem and getting the target body potential distribution. Finally, the voltage signal can be calculated. The simulation results show that compared to the acoustic parameter value usually used in the approximate calculation, the voltage signal error of the muscle tissue is the largest of the seven groups of parameters under the same condition. The results of the study laid the foundation for the study of the influence of the acoustically inhomogeneous model of human tissue on the magneto-acoustic -electrical tomography.

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Image Reconstruction in Magnetoacoustic Tomography With Magnetic Induction With Variable Sound Speeds

Cited by 12 publications

References 32 publications

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

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

Analysis of the Singular Values for Conductivity Reconstruction in Magneto-Acoustic Tomography With Magnetic Induction

Study on the Influence of Acoustically Inhomogeneous Characteristics on Magneto-acoustic-electrical Tomography

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