Three-dimensional electrical impedance tomography

THE electrical resistivity of mammalian tissues varies widely1–5 and is correlated with physiological function6–8. Electrical impedance tomography (EIT) can be used to probe such variations in vivo, and offers a non-invasive means of imaging the internal conductivity distribution of the human body9–11. But the computational complexity of EIT has severe practical limitations, and previous work has been restricted to considering image reconstruction as an essentially two-dimensional problem10,12. This simplification can limit significantly the imaging capabilities of EIT, as the electric currents used to determine the conductivity variations will not in general be confined to a two-dimensional plane13. A few studies have attempted three-dimensional EIT image reconstruction14,15, but have not yet succeeded in generating images of a quality suitable for clinical applications. Here we report the development of a three-dimensional EIT system with greatly improved imaging capabilities, which combines our 64-electrode data-collection apparatus16 with customized matrix inversion techniques. Our results demonstrate the practical potential of EIT for clinical applications, such as lung or brain imaging and diagnostic screening8.

[1]  J P Morucci,et al.  3D reconstruction in electrical impedance imaging using a direct sensitivity matrix approach. , 1995, Physiological measurement.

[2]  Brian H. Brown,et al.  Imaging spatial distributions of resistivity using applied potential tomography , 1983 .

[3]  S G Dawids,et al.  Evaluation of applied potential tomography: a clinician's view. , 1987, Clinical physics and physiological measurement : an official journal of the Hospital Physicists' Association, Deutsche Gesellschaft fur Medizinische Physik and the European Federation of Organisations for Medical Physics.

[4]  K. Foster,et al.  Dielectric properties of mammalian tissues from 0.1 to 100 MHz: a summary of recent data. , 1982, Physics in medicine and biology.

[5]  J Jossinet,et al.  Tissue impedance: a historical overview. , 1995, Physiological measurement.

[6]  F. Duck.  Physical properties of tissue , 1990 .

[7]  David S. Holder,et al.  Clinical and physiological applications of electrical impedance tomography , 1993 .

[8]  Francis A. Duck,et al.  Electrical Properties of Tissue , 1990 .

[9]  D. Geselowitz.  An application of electrocardiographic lead theory to impedance plethysmography. , 1971, IEEE transactions on bio-medical engineering.

[10]  S. B. Childs,et al.  INVERSE PROBLEMS IN PARTIAL DIFFERENTIAL EQUATIONS. , 1968 .

[11]  D C Barber,et al.  A sensitivity method for electrical impedance tomography. , 1989, Clinical physics and physiological measurement : an official journal of the Hospital Physicists' Association, Deutsche Gesellschaft fur Medizinische Physik and the European Federation of Organisations for Medical Physics.

[12]  B H Brown,et al.  Clinical applications of electrical impedance tomography. , 1993, Journal of medical engineering & technology.

[13]  Naresh K. Sinha,et al.  Regression and the Moore-Penrose pseudoinverse : Arthur Albert. 180 pages, diagrams, 6 × 9 in. New York, London, Academic Press, 1972. Price not available. , 1974 .

[14]  C. J. Kotre,et al.  A sensitivity coefficient method for the reconstruction of electrical impedance tomograms. , 1989, Clinical physics and physiological measurement : an official journal of the Hospital Physicists' Association, Deutsche Gesellschaft fur Medizinische Physik and the European Federation of Organisations for Medical Physics.

[15]  K S Rabbani,et al.  Studies on the effect of the third dimension on a two-dimensional electrical impedance tomography system. , 1991, Clinical physics and physiological measurement : an official journal of the Hospital Physicists' Association, Deutsche Gesellschaft fur Medizinische Physik and the European Federation of Organisations for Medical Physics.

[16]  R. Pethig,et al.  Dielectric properties of body tissues. , 1987, Clinical physics and physiological measurement : an official journal of the Hospital Physicists' Association, Deutsche Gesellschaft fur Medizinische Physik and the European Federation of Organisations for Medical Physics.

[17]  B H Brown,et al.  The Sheffield data collection system. , 1987, Clinical physics and physiological measurement : an official journal of the Hospital Physicists' Association, Deutsche Gesellschaft fur Medizinische Physik and the European Federation of Organisations for Medical Physics.