Hybrid tomography for conductivity imaging

Abstract

Hybrid imaging techniques utilize couplings of physical modalities -they are called hybrid, because, typically, the excitation and measurement quantities belong to different modalities. Recently there has been an enormous research interest in this area because these methods promise very high resolution. In this paper we give a review on hybrid tomography methods for electrical conductivity imaging. The reviewed imaging methods utilize couplings between electric, magnetic and ultrasound modalities. By this it is possible to perform high-resolution electrical impedance imaging and to overcome the low-resolution problem of electric impedance tomography.

Imaging from coupled physics

“…In the majority of these imaging modalities, either the useful contrast is of low resolution, or high resolution images are obtained with limited contrast or quantitative discriminatory ability. In the last decade, an alternative phenomenon has become of increasing interest, although its origins can be traced much further back; see Widlak and Scherzer [1], Kuchment and Steinhaur [2], and Seo et al [3] in this issue for references to this historical context. Rather than using the same physical field for probing and measurement, with a contrast caused by perturbation, these methods exploit the generation of a secondary physical field which can be measured in addition to, or without, the often dominating effect of the primary probe field.…”

“…This topic, known as current density imaging (CDI) or magnetic resonance elecrical impedance tomography (MREIT), and its related technique of magnetic resonance electrical property tomography (MREPT), is reviewed by Wildak and Scherzer [1], and also by Seo et al [3], where experimental studies are documented. Mathematically, several of the ICP problems can be analyzed in terms of the 'p-Laplacian' which raises interesting research questions of non-linear partial differential equations.…”

Detection of breathing‐type damage using multiharmonic electrical impedance tomography

“…More recently, hybrid methodologies were also investigated in an effort to improve the conditioning of the inverse problem and consequently the quality of the tomographic images in terms of both contrast and resolution. Hybrid methods rely on coupled‐physics approaches where typically two field quantities are simultaneously used to characterize the response of the medium . Practical examples are the impedance‐acoustic tomography where the electrical field is combined with the acoustic field to obtain high contrast EIT images.…”

An Instrumental Electrode Configuration for 3-D Ultrasound Modulated Electrical Impedance Tomography

“…Recently, hybrid imaging techniques have been investigated to obtain more effective measurement information and reduce the ill-posed nature of the inverse problem for conventional EIT [5–8]. The hybrid imaging described here refers to techniques involving interaction of physical processes, which are different from fusing images of different modalities.…”