Lorentz force electrical impedance tomography using pulse compression technique

Sun, Zhishen; Liu, Guoqiang; Xia, Hui

doi:10.1088/1674-1056/26/12/124302

Cited by 14 publications

(14 citation statements)

References 18 publications

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“…In order to effectively obtain the magneto-acoustic signals with high SNR, injecting LM into the detected tissue to improve the intensity of the magneto-acoustic signal was proposed ( 18 ). Furthermore, we previously proposed a method to locate the spatial distribution of LM using the envelope of the magneto-acoustic signal collected in a circle ( 19 ). Therefore, in the field of biological tissue electrical impedance imaging technology, LM has broad application potential as MAT signal enhancement medium or conductivity comparison medium.…”

Section: Introductionmentioning

confidence: 99%

Liquid metal injected from interstitial channels for inhibiting subcutaneous hepatoma growth and improving MRI/MAT image contrast

Yang

Xia

et al. 2022

Front. Oncol.

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ObjectiveLiquid metal (LM) nowadays is considered a new biomedical material for medical treatment. The most common application of LM in medical therapy is taking LM as a carrier for oncology therapeutics. However, the feasibility and direct effect of LM in tumor treatment are still unknown, and how to delineate the negative resection margin (NRM) of the tumor is also a crucial problem in surgery. We aimed to inject LM into interstitial channels of extremities of mice to overlay the surface of the primary tumor to investigate the effect of LM on inhibiting tumor growth and highlight the NRM of the tumor.MethodsIn this study, all 50 BALB/c-nude female mice were used to construct the transplanted HepG2-type hepatocellular carcinoma model. One week after the establishment of the model, the mice were divided into three groups, named LM group, PBS group and Control group by injecting different liquid materials into the forelimb interstitial channel of the mice. T2WI image on MRI and Magneto-acoustic tomography (MAT) were used to show the distribution of LM and PBS in vivo. The group comparisons of tumor growth and blood tests were evaluated by one-way ANOVA and post-hoc analysis. And the biocompatibility of LM to BALB/c nude mice was evaluated by histopathological analysis of LM group and control group.ResultsThe volume change ratio of tumor was significantly lower in LM group than in PBS and Control group after 10 days of grouping. Compared with PBS and Control group, the main indexes of blood tests in LM group were significantly lower and close to normal level. In addition, the distribution of LM in vivo could be clearly observed under T2WI anatomic images and the crossprofile of the tumor in MAT. LM also has a obvious contrast in MRI T2WI and enhanced the amplitude of imaging signal in MAT.ConclusionLM may inhibit the growth of transplanted hepatoma tumor through tumor encapsulation. In vivo, tumor imaging and LM distribution imaging were achieved by MRI T2WI, which verified that LM injected with interstitial injection made the NRM of tumor more prominent and had the potential of being MRI contrast agent. At the same time, LM could also be a new conductive medium to improve the imaging quality of MAT. Moreover, LM performed mild biocompatibility.

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Section: Introductionmentioning

confidence: 99%

Liquid metal injected from interstitial channels for inhibiting subcutaneous hepatoma growth and improving MRI/MAT image contrast

Yang

Xia

et al. 2022

Front. Oncol.

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“…A focal probe was utilized for steps that can focus excitation on enhancing the imaging resolution [19]. Sun et al applied pulse compression technology in MAET and proved its feasibility through simulated experiments [20].…”

Section: Introductionmentioning

confidence: 99%

“…All of the above MAET research references are aimed at gel phantoms of low salinity solid [17][18][19][20] or from animal tissue samples [12,18,19]. No relevant research has been carried out on lung tissue that is porous and contains air.…”

Section: Introductionmentioning

confidence: 99%

Research on Pneumothorax Detection Based on Magneto-Acousto-Electrical Tomography

Li¹,

Li²,

Liu³

2021

PIER M

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Pneumothorax can cause chest tightness, chest pain, and respiratory failure, which can be life-threatening in severe cases. Therefore, early diagnosis and treatment of pneumothorax are crucial. Magneto-Acousto-Electrical Tomography (MAET) is an imaging technique in which ultrasound and electromagnetism are mutually coupled. It has the advantages of high spatial resolution and high image contrast. In this paper, we use MAET to study porous and air-containing lung tissue. We first simulate the characteristics of the MAET signal as the degree of pneumothorax increases. The relationship between the size of the ultrasonic probe and the size of the pneumothorax was discussed. The simulation results show that the reflection and attenuation values of the MAET voltage signals increase as the pneumothorax size gradually increases, regardless of whether the ultrasound transducer size is larger or smaller than the pneumothorax size. Finally, the MAET experimental platform was built to validate the simulation results of MAET signals. The results of the experiment and simulation are consistent with each other. The research of this paper has a certain reference value for the detection of pneumothorax using MAET.

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“…Thus, electrical conductivity tomography for biological tissue is hopefully likely to become one of the most effective tumor assessment modalities for the early diagnosis of cancer [ 3 ], and recently, health information relating the physiological and pathological condition of biological tissues has been obtained by detecting electrical conductivity [ 4 ], whereby the main measurement means is electrical impedance tomography (EIT) [ 5 ]. Despite having the strength of high contrast, EIT is limited by the quantity of the electrodes [ 3 ] and the ill-posed nature of the inverse problem [ 6 ], which means it barely achieves a high imaging resolution [ 7 ]. Combining the magnetic resonance current density imaging and the EIT technique, magnetic resonance electrical impedance tomography provides cross-sectional conductivity images of an object’s high spatial resolution impedance information [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

“…The resolution of that method could be further improved. In current MAET research, either a plane probe [ 6 ] or a high-voltage narrow pulse excitation signal was used, which resulted in the poor resolution of the conductivity imaging and the excessive instantaneous excitation power of the probe. To solve these problems, we designed and implemented a MAET system using a high-power focal probe and a chirp signal with sweep frequency ranging from 2 MHz to 3 MHz.…”

Section: Introductionmentioning

confidence: 99%

A 2D Magneto-Acousto-Electrical Tomography Method to Detect Conductivity Variation Using Multifocus Image Method

Ming

Chen

Sun

et al. 2018

Sensors

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As magneto-acoustic-electrical tomography (MAET) combines the merits of high contrast and high imaging resolution, and is extremely useful for electrical conductivity measurement, so it is expected to be a promising medical imaging modalities for diagnosis of early-stage cancer. Based on the Verasonics system and the MC600 displacement platform, we designed and implemented a MAET system with a chirp pulse stimulation (MAET-CPS) method and a focal probe was utilized for stepscan focus excitation to enhance the imaging resolution. The relevant experiments were conducted to explore the influence of excitation positions of the single-focus point, and the effect of the excitation position on the amplitudes of the conductivity variation was clearly demonstrated. In order to take advantage of the merits of multifocus imaging, we firstly proposed a single focus MAET system with a chirp pulse stimulation (sfMAET-CPS) method and a multifocus MAET system with a chirp pulse stimulation (mfMAET-CPS) method for high-resolution conductivity imaging, and a homogenous gelatin phantom with a cuboid-shaped hole was used to investigate the accuracy of mfMAET-CPS. Comparative experiments were carried out on the same uniform phantom by the sfMAET-CPS and the mfMAET-CPS, respectively. The results showed that: (1) the electrical conductivity distributions of the homogenous phantom with a cuboid-shaped hole were detected by the sfMAET-CPS but were easily affected by the focal point, which demonstrated that the sfMAET-CPS had a low imaging resolution. (2) Compared with the sfMAET-CPS, the imaging effect of the mfMAET-CPS was much better than that of the sfMAET-CPS. (3) A linear interpolation algorithm was used to process the 2D conductivity distribution; it increased the smoothness of the conductivity distribution and improved the imaging effect. The stepscan focus excitation and the linearly frequency-modulated theory provide an alternative scheme for the clinical application of MAET.

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Lorentz force electrical impedance tomography using pulse compression technique

Cited by 14 publications

References 18 publications

Liquid metal injected from interstitial channels for inhibiting subcutaneous hepatoma growth and improving MRI/MAT image contrast

Liquid metal injected from interstitial channels for inhibiting subcutaneous hepatoma growth and improving MRI/MAT image contrast

Research on Pneumothorax Detection Based on Magneto-Acousto-Electrical Tomography

A 2D Magneto-Acousto-Electrical Tomography Method to Detect Conductivity Variation Using Multifocus Image Method

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