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Titolo:
ELECTRICAL-IMPEDANCE TOMOGRAPHY OF COMPLEX CONDUCTIVITY DISTRIBUTIONSWITH NONCIRCULAR BOUNDARY
Autore:
JAIN H; ISAACSON D; EDIC PM; NEWELL JC;
Indirizzi:
RENSSELAER POLYTECH INST,DEPT BIOMED ENGN TROY NY 12180 RENSSELAER POLYTECH INST,DEPT MATH SCI TROY NY 12180 GE CO,CTR CORP RES & DEV SCHENECTADY NY 12309
Titolo Testata:
IEEE transactions on biomedical engineering
fascicolo: 11, volume: 44, anno: 1997,
pagine: 1051 - 1060
SICI:
0018-9294(1997)44:11<1051:ETOCCD>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
CURRENT COMPUTED-TOMOGRAPHY; FINITE-ELEMENT; TORSO MODEL; POTENTIALS;
Keywords:
BOUNDARY ELEMENT METHOD; COMPLEX CONDUCTIVITY; FINITE ELEMENT METHOD; IMPEDANCE TOMOGRAPHY; ITERATIVE RECONSTRUCTION ALGORITHM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
21
Recensione:
Indirizzi per estratti:
Citazione:
H. Jain et al., "ELECTRICAL-IMPEDANCE TOMOGRAPHY OF COMPLEX CONDUCTIVITY DISTRIBUTIONSWITH NONCIRCULAR BOUNDARY", IEEE transactions on biomedical engineering, 44(11), 1997, pp. 1051-1060

Abstract

Electrical impedance tomography (EIT) uses low-frequency current and voltage measurements made on the boundary of a body to compute the conductivity distribution within the body. Since the permittivity distribution inside the body also contributes significantly to the measured voltages, the present reconstruction algorithm images complex conductivity distributions. A finite element model (FEM) is used to solve the forward problem, using a 6017-node mesh for a piecewise-linear potential distribution. The finite element solution using this mesh is compared with the analytical solution for a homogeneous field and a maximum error of 0.05% is observed in the voltage distribution. The boundary element method (BEM) is also used to generate the voltage data for inhomogeneous conductivity distributions inside regions with noncircular boundaries. An iterative reconstruction algorithm is described for approximating both the conductivity and permittivity distributions from this data. The results for an off-centered inhomogeneity showed a 35% improvement in contrast from that seen with only one iteration, for both the conductivity and the permittivity values. It is also shown that a significant improvement in images results from accurately modeling a noncircular boundary. Both static and difference images are distorted by assuming a circular boundary and the amount of distortion increases significantly as the boundary shape becomes more elliptical. For a homogeneous field in an elliptical body with axis ratio of 0.73, an imagereconstructed assuming the boundary to be circular has an artifact atthe center of the image with an error of 20%. This error increased to37% when the axis ratio was 0.64. A reconstruction algorithm which used a mesh with the same axis ratio as the elliptical boundary reduced the error in the conductivity values to within 0.5% of the actual values.

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Documento generato il 08/04/20 alle ore 09:13:17