Enhancing Impedance Imaging Through Multimodal Tomography

Abstract

Abstract-Several noninvasive modalities including electrical impedance tomography (EIT), magnetic induction tomography (MIT) and induced-current EIT (ICEIT) have been developed for imaging the electrical conductivity distribution within a human body. Although these modalities differ in how the excitation and detection circuitry (electrodes or coils) are implemented, they share a number of common principles not only within the image reconstruction approaches but also with respect to the basic principle of generating a current density distribution inside a body and recording the resultant electric fields. In this paper, we are interested in comparing differences between these modalities and in theoretically understanding the compromises involved, despite the increased hardware cost and complexity that such a multi-modal system brings along. To systematically assess the merits of combining data, we performed 3-D simulations for each modality and for the multi-modal system by combining all available data. The normalized sensitivity matrices were computed for each modality based on the finite element method and singular value decomposition was performed on the resultant matrices. We used both global and regional quality measures to evaluate and compare different modalities. This study has shown that the condition number of the sensitivity matrix obtained from the multi-modal tomography with 16-electrode and 16-coil is much lower than the condition number produced in the conventional 16-channel EIT and MIT systems, and thus, produced promising results in terms of image stability. An improvement of about 20% in image resolution can be achieved considering feasible signal to noise ratio (SNR) levels.

Imaging of hemorrhagic stroke in magnetic induction tomography: An in vitro study

“…The average of multiple measurements increased the total computation time as it takes 16 s to obtain one frame of MIT measurement data with the combination of 16 excitation × 16 detection channels. However, a fast data acquisition system was achieved by Maimaitijiang et al (), therefore exploiting advanced hardware and parallel algorithms could be an option to achieve a fast MIT system. Wavelet based denoising algorithms with adaptive regularization (Maimaitijiang et al, ) were found to be an effective means to lower the detectability threshold and augment image quality while hardware improvement (Wee et al, ) and combined multi‐modality approaches (Gürsoy et al, ) were proposed for improving measurement accuracy and image quality respectively.…”

“…Effectively utilizing advanced hardware and modeling errors (Gürsoy et. al., b, ), signal/image processing techniques to improve stroke detectability and to provide dynamic adaptation to environmental alterations and system instability could provide the performance required for clinical applications.…”

Advancements in Transmitters and Sensors for Biological Tissue Imaging in Magnetic Induction Tomography

“…This phenomenon is due to the relatively low conductivity of the tissue [35,45]. Griffiths [46] had noticed that the expected perturbation of the received signal due to conduction of eddy currents within biological tissues, which is 1% of the primary signal, was still small, even with the use of high frequency (HF) excitation fields (10 MHz).…”

Reconstitution of Food Powders Granulated with Oil‐in‐Water Emulsions

“…Water is probably the most commonly used liquid binder, but an interesting example of alternative binder for pharmaceutical wet granulation is represented by an oil-in-water microemulsion to produce solid self-emulsifying drug delivery systems (solid-SEDDS) able to increase the bioavailability of poorly water-solu-ble drugs [4,5]. E. Franceschinis et al [6] reported that the presence of oil, when a microemulsion is used as liquid binder, acts as lubricating medium, generating more plastic and deformable granules with a reduced disintegration time.…”