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Exploratory study on the methodology of fast imaging of unilateral stroke lesions by electrical impedance asymmetry in human heads.

Ma J, Xu C, Dai M, You F, Shi X, Dong X, Fu F - ScientificWorldJournal (2014)

Bottom Line: Diagnosing stroke is not a problem for hospitals with CT, MRI, and other imaging devices but is difficult for community hospitals without these devices.In this technique, electrical impedance tomography (EIT) data measured from the undamaged craniocerebral hemisphere (CCH) is regarded as reference data for the remaining EIT data measured from the other CCH for difference imaging to identify the differences in resistivity distribution between the two CCHs.The results of SEIT imaging based on simulation data from the 2D human head finite element model and that from the physical phantom of human head verified this method in detection of unilateral stroke.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Fourth Military Medical University, Xi'an 710032, China.

ABSTRACT
Stroke has a high mortality and disability rate and should be rapidly diagnosed to improve prognosis. Diagnosing stroke is not a problem for hospitals with CT, MRI, and other imaging devices but is difficult for community hospitals without these devices. Based on the mechanism that the electrical impedance of the two hemispheres of a normal human head is basically symmetrical and a stroke can alter this symmetry, a fast electrical impedance imaging method called symmetrical electrical impedance tomography (SEIT) is proposed. In this technique, electrical impedance tomography (EIT) data measured from the undamaged craniocerebral hemisphere (CCH) is regarded as reference data for the remaining EIT data measured from the other CCH for difference imaging to identify the differences in resistivity distribution between the two CCHs. The results of SEIT imaging based on simulation data from the 2D human head finite element model and that from the physical phantom of human head verified this method in detection of unilateral stroke.

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Image reconstruction model. The image reconstruction model consisted of 1804 triangular elements, 984 nodes, and 16 electrodes. The model was used for image reconstructions in all imaging experiments, including simulation and physical phantom experiments (A: anterior; P: posterior; L: left; and R: right).
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fig3: Image reconstruction model. The image reconstruction model consisted of 1804 triangular elements, 984 nodes, and 16 electrodes. The model was used for image reconstructions in all imaging experiments, including simulation and physical phantom experiments (A: anterior; P: posterior; L: left; and R: right).

Mentions: SEIT image reconstruction is similar to general difference EIT imaging. When a frame of SEIT reference data Vref was constructed, the damped least squares image reconstruction algorithm [30] was utilized for difference EIT image reconstruction. According to the changes in EIT boundary voltages (ΔV), difference EIT image reconstruction solved the changes in the internal resistivity of the measured subject with(2)Δρ=BΔV.In (2), matrix B is the image reconstruction matrix calculated from sensitivity coefficient matrix S [30]. Matrix S is the linearized sensitivity matrix, and its elements reflect the relationship between the resistivity changes in the finite elements of the imaging region and the changes in the EIT boundary voltages. Matrix S was acquired by solving EIT forward problems [30] with an image reconstruction model (Figure 3). The changes in EIT boundary voltages were calculated according to(3)ΔV=Vcur−VrefVref.During image reconstruction, the image reconstruction software directly employed the reconstruction model and image reconstruction matrix B to calculate (2) and to visualize the reconstructed image.


Exploratory study on the methodology of fast imaging of unilateral stroke lesions by electrical impedance asymmetry in human heads.

Ma J, Xu C, Dai M, You F, Shi X, Dong X, Fu F - ScientificWorldJournal (2014)

Image reconstruction model. The image reconstruction model consisted of 1804 triangular elements, 984 nodes, and 16 electrodes. The model was used for image reconstructions in all imaging experiments, including simulation and physical phantom experiments (A: anterior; P: posterior; L: left; and R: right).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4060593&req=5

fig3: Image reconstruction model. The image reconstruction model consisted of 1804 triangular elements, 984 nodes, and 16 electrodes. The model was used for image reconstructions in all imaging experiments, including simulation and physical phantom experiments (A: anterior; P: posterior; L: left; and R: right).
Mentions: SEIT image reconstruction is similar to general difference EIT imaging. When a frame of SEIT reference data Vref was constructed, the damped least squares image reconstruction algorithm [30] was utilized for difference EIT image reconstruction. According to the changes in EIT boundary voltages (ΔV), difference EIT image reconstruction solved the changes in the internal resistivity of the measured subject with(2)Δρ=BΔV.In (2), matrix B is the image reconstruction matrix calculated from sensitivity coefficient matrix S [30]. Matrix S is the linearized sensitivity matrix, and its elements reflect the relationship between the resistivity changes in the finite elements of the imaging region and the changes in the EIT boundary voltages. Matrix S was acquired by solving EIT forward problems [30] with an image reconstruction model (Figure 3). The changes in EIT boundary voltages were calculated according to(3)ΔV=Vcur−VrefVref.During image reconstruction, the image reconstruction software directly employed the reconstruction model and image reconstruction matrix B to calculate (2) and to visualize the reconstructed image.

Bottom Line: Diagnosing stroke is not a problem for hospitals with CT, MRI, and other imaging devices but is difficult for community hospitals without these devices.In this technique, electrical impedance tomography (EIT) data measured from the undamaged craniocerebral hemisphere (CCH) is regarded as reference data for the remaining EIT data measured from the other CCH for difference imaging to identify the differences in resistivity distribution between the two CCHs.The results of SEIT imaging based on simulation data from the 2D human head finite element model and that from the physical phantom of human head verified this method in detection of unilateral stroke.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Fourth Military Medical University, Xi'an 710032, China.

ABSTRACT
Stroke has a high mortality and disability rate and should be rapidly diagnosed to improve prognosis. Diagnosing stroke is not a problem for hospitals with CT, MRI, and other imaging devices but is difficult for community hospitals without these devices. Based on the mechanism that the electrical impedance of the two hemispheres of a normal human head is basically symmetrical and a stroke can alter this symmetry, a fast electrical impedance imaging method called symmetrical electrical impedance tomography (SEIT) is proposed. In this technique, electrical impedance tomography (EIT) data measured from the undamaged craniocerebral hemisphere (CCH) is regarded as reference data for the remaining EIT data measured from the other CCH for difference imaging to identify the differences in resistivity distribution between the two CCHs. The results of SEIT imaging based on simulation data from the 2D human head finite element model and that from the physical phantom of human head verified this method in detection of unilateral stroke.

Show MeSH
Related in: MedlinePlus