Multiplicative contrast source inversion method in electrical properties tomography based on Jacobi matrix inversion

The tissue electrical properties of conductivity and permittivity affect the interactions of electromagnetic fields in the body. These properties vary throughout the different tissues as the tissue structure and composition varies. In this thesis, medical imaging and diagnosis is used as primary example to motivate exploration of a novel...

Deep Learning Enhanced Contrast Source Inversion And Phase Error Based Conductivity Correction For Electrical Properties Tomography: Exploration Of Physics-Assisted Deep Learning Methodology For Magnetic Resonance Based Electrical Properties Tomography

Magnetic resonance electrical properties tomography is a type of quantitative magnetic resonance imaging that aims to reconstruct the conductivity and permittivity of biological tissue. These electrical properties of the tissue can be used to compute the specific absorption rate, to differentiate tumours from healthy tissue and for hyperthermia...

Contrast source inversion on experimental data: Initial results

Quantitative images showing the speed of sound proffle of the breast may be obtained by employing full-waveform inversion (FWI) methods on the measured data. These reconstruction methods work well for both dense and normal breasts. Contrast source inversion (CSI) is a frequency domain FWI method. In literature, many examples of successful...

Transceive phase corrected 2D contrast source inversion-electrical properties tomography

Purpose: To remove the necessity of the tranceive phase assumption for CSI-EPT and show electrical properties maps reconstructed from measured data obtained using a standard 3T birdcage body coil setup. Methods: The existing CSI-EPT algorithm is reformulated to use the transceive phase rather than relying on the transceive phase assumption....

Effects of Simulated Error-Sources on Different 3-D CSI-EPT Strategies

Three-dimensional contrast source inversion-electrical properties tomography (3-D CSI-EPT) is an iterative reconstruction method that estimates the electrical properties of tissue from transmit field magnetic resonance data. However, in order to bring 3-D CSI-EPT into practice for complex tissue structures and to understand the origin and...

Developments in electrical-property tomography based on the contrast-source inversion method

The main objective of electrical-property tomography (EPT) is to retrieve dielectric tissue parameters from B ₁ ⁺ data as measured by a magnetic-resonance (MR) scanner. This is a so-called hybrid inverse problem in which data are defined inside the reconstruction domain of interest. In this paper, we discuss recent and...

Combining deep learning and 3D contrast source inversion in MR-based electrical properties tomography

Magnetic resonance electrical properties tomography (MR-EPT) is a technique used to estimate the conductivity and permittivity of tissues from MR measurements of the transmit magnetic field. Different reconstruction methods are available; however, all these methods present several limitations, which hamper the clinical applicability. Standard...

3-D Contrast Source Inversion-Electrical Properties Tomography

Contrast source inversion – electrical properties tomography (CSI-EPT) is an iterative reconstruction method to retrieve the electrical properties (EPs) of tissues from MR data. The method is based on integral representations of the electromagnetic (EM) field and has been shown to allow EP reconstructions of small structures as...

Inversion of Multifrequency Data With the Cross-Correlated Contrast Source Inversion Method

Cross-correlated contrast source inversion (CC-CSI) is a nonlinear iterative inversion method that is proposed recently for solving the inverse scattering problems. In CC-CSI, a cross-correlated error is constructed and introduced to the cost functional, which improves the inversion ability when compared to the classical design of the cost...

CSI-EPT: Towards practical implementation

The information of electrical properties of biological tissues within human body can be useful information for diagnosis, tissue characterization, hyperthermia treatment planning and MR safety control.<br/>CSI-EPT is an MR base imaging modality, which reconstructs the electrical properties of the sample. However, this method have not been...

Transceive Phase Corrected Contrast Source Inversion-Electrical Properties Tomography

Electrical properties tomography is the quantification of the conductivity and permittivity of different materials. In an MRI setting this can be used to map the electrical properties of tissue. These values can be used as a different contrast mechanism, for hyperthermia treatment or the improvement of antenna design for specific applications....

Cross-Correlated Contrast Source Inversion

In this paper, we improved the performance of the contrast source inversion (CSI) method by incorporating a so-called cross-correlated cost functional, which interrelates the state error and the data error in the measurement domain. The proposed method is referred to as the cross-correlated CSI. It enables better robustness and higher inversion...

Three-Dimensional Contrast Source Inversion-Electrical Properties Tomography: 3D CSI-EPT

The electrical properties (EPs) conductivity and permittivity of biological tissue inside the human body provide diagnostic information of those tissues. This allows differentiation between tumors and healthy tissue and quantification of the specific absorption rate (SAR) of the tissues. Visualizing the EPs based on measurable magnetic radio...

B1-based SAR reconstruction using contrast source inversion–electric properties tomography (CSI-EPT)

Specific absorption rate (SAR) assessment is essential for safety purposes during MR acquisition. Online SAR assessment is not trivial and requires, in addition, knowledge of the electric tissue properties and the electric fields in the human anatomy. In this study, the potential of the recently developed CSI-EPT method to reconstruct SAR...