Direct 2-D reconstructions of conductivity and permittivity from EIT data on a human chest

Abstract

A novel direct D-bar reconstruction algorithm is presented for reconstructing a complex conductivity distribution from 2-D EIT data. The method is applied to simulated data and archival human chest data. Permittivity reconstructions with the aforementioned method and conductivity reconstructions with the previously existing nonlinear D-bar method for real-valued conductivities depicting ventilation and perfusion in the human chest are presented. This constitutes the first fully nonlinear D-bar reconstructions of human chest data and the first D-bar permittivity reconstructions of experimental data. The results of the human chest data reconstructions are compared on a circular domain versus a chest-shaped domain.

Figures

Fig. 1.

The circular and chest-shaped domains used in the reconstructions of the human chest. rmaxcircle = 0.1432 m. rmaxchest = 0.1702 m.

Fig. 2.

Tests with simulated data. First column: Numerical phantom including lungs, heart, and spine. Second column: Reconstruction. Third column: Error = |Phantom − Reconstruction|. Top row: Conductivity. Bottom row: Permittivity.

Fig. 3.

Tests with simulated data. First column: Numerical phantom including high conductivity, low permittivity fluid in one lung. Second column: Reconstruction Third column: Error = |Phantom − Reconstruction|. Top row: Conductivity. Bottom row: Permittivity.

Fig. 4.

Selection of 8 reconstructed frames of the conductivity and permittivity distribution in a healthy human subject during breathholding (images displayed with the heart at the top). The images depict changes in blood flow, with red representing high conductivity/permittivity and blue low conductivity/permittivity. Moving from left to right, the first four frames depict diastole, the 5th and 6th depict systole, and in the last two frames, diastole is resuming.

Fig. 5.

Selection of 8 reconstructed frames of the conductivity and permittivity distribution in a healthy human subject during breathholding (images displayed with the heart at the top). The images depict changes in blood flow, with red representing high conductivity/permittivity and blue low conductivity/permittivity. Moving from left to right, the first four frames depict diastole, the 5th and 6th depict systole, and in the last two frames, diastole is resuming.

Fig. 6.

Selection of 5 reconstructed frames of the conductivity and permittivity distributions in a healthy human subject during a slow ventilation maneuver (images displayed with the heart at the top.) Top row: Red is high resistivity and blue low resistivity. Bottom row: Red is high permittivity and blue low permittivity.