Abstract
A recently developed Focused Impedance Measurement (FIM) system (by the authors’ group) uses six electrodes to localize a zone of interest. Because of 3D sensitivity it could give physiological information on large organs like stomach, lungs, etc. using surface electrodes in the frontal plane. This paper presents a modified FIM technique using four electrodes placed at the corners of a square matrix. Firstly current is driven through an adjacent electrode pair while the potential is measured across the opposite pair from which an impedance value is obtained. Then a similar measurement is made at 90° to the above by changing connections to the electrode pairs appropriately. The sum of these two impedance values has a dominant contribution from the central region within the square matrix, giving the desired focusing. Experimental sensitivity maps obtained from a 2D phantom have verified the focusing effect. Compared to the previous six-electrode FIM system the focusing effect is slightly less, but this new technique has less negative artifacts in the periphery. This new FIM method can be applied both in the frontal plane and in the transverse plane of the human thorax, giving a further advantage besides requiring fewer electrodes.
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Barber D. C., B. H. Brown. Applied potential tomography. J. Phys. E Sci. Instrum. 17:723–733, 1984
Brown B. H., D. C. Barber, A. D. Seager. Applied potential tomography: possible clinical applications. Clin. Phys. Physiol. Meas. 6:109–121, 1985
Brown B. H., J. A. Tidy, K. Boston, A. D. Blackett, R. H. Smallwood, F. Sharp. The relationship between tissue structure and imposed electrical current flow in cervical neoplasia. Lancet 355:892–895, 2000
Geselowitz D. B. An application of electrocardiographic lead theory to impedance plethysmography. IEEE Trans. Biomed. Eng. BME 18:38–41, 1971
Leathard A. D., B. H. Brown, J. Campbell, F. Zhang, A. H. Morice, D. Tayler. A comparison of ventilatory and cardiac related changes in EIT images of normal human lungs and lungs with pulmonary emboli. Physiol. Meas. 15:A137–A146, 1994
Rabbani, K. S., M. Hassan, A. B. M. H. Kabir, M. Ahmed, and S. Nahar. Electrical impedance tomography (EIT) in the frontal plane using ring electrode configuration. In: Proceedings, Regional Conference of IEEE-EMBS and 14th BMES-India, Delhi, 1995, pp. 1.43–1.44
Rabbani K. S., M. Hassan, A. Kiber. 3D object localisation using EIT measurements at two levels. Physiol. Meas. 17:189–199, 1993
Rabbani K. S., H. Kabir. Studies on the effect of the third dimension on a two dimensional electrical impedance tomography system. Clin. Phys. Physiol. Meas. 12:393–402, 1991
Rabbani, K. S., M. Sarker, M. H. R. Akond, and T. Akter. Focused impedance measurement (FIM)—a new technique with zone localization. In: Proceedings, X International Conference on Electrical Bioimpedance, Barcelona, Spain, 1998, pp. 31–34
Rabbani K. S., M Sarker, M. H. R Akond, T Akter. Focused impedance measurement (FIM)—a new technique with improved zone localization. Ann. N. Y. Acad. Sci. Electr. Bioimpedance Methods 873:408–420, 1999
Sarker, S. A., P. K. Bardhan, K. S. Rabbani, N. H. Alam, M. Hassan, A. Kiber, R. Zaman, D. Mahalanabis, and K. Gyr. Noninvasive assessment of gastric acid secretion by applied potential tomography. Abstracts, 4th meeting of the European Society of Gastrenterology, Berlin, September 1995, pp. 19–24
Taktak A., A. Spencer, P. Record, R. Gadd, P. Rolfe. Feasibility of neonatal lung imaging using electrical impedance tomography. Early Hum. Dev. 44:131–138, 1996
Vauhkonen P. J., M. Vauhkonen, T. Savolainen, J. P. Kaipio. Static three-dimensional electrical impedance tomography. Ann. N. Y. Acad. Sci. Electr. Bioimpedance Methods 873:472–481, 1999
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Rabbani, K., Karal, M. A New Four-Electrode Focused Impedance Measurement (FIM) System for Physiological Study. Ann Biomed Eng 36, 1072–1077 (2008). https://doi.org/10.1007/s10439-008-9470-7
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DOI: https://doi.org/10.1007/s10439-008-9470-7