Source localization in an inhomogeneous physical thorax phantom

Tenner, U.; Haueisen, Jens; Nowak, H.; Leder, U.; Brauer, Hartmut

doi:10.1088/0031-9155/44/8/309

Cited by 29 publications

(19 citation statements)

References 25 publications

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“…This means that the distribution based on the L\ norm is very peaked while the distribution based on the Li norm is very smeared. In order to evaluate the influence of the different norms for the data and the model term in the CDRs, we have computed the kunosis for the L p norm with p d and p rn varying between 1 and 2, where /?,/ and p m have been used for the norms of the data and the model term according to (1). The regularization factor λ has been kept at a fixed value in order to make the kurtosis values directly comparable.…”

Section: Resultsmentioning

confidence: 99%

Application of Kurtosis to the Interpretation of Current Density Reconstructions

Ziółkowski¹,

Haueisen²

2001

Biomedizinische Technik/Biomedical Engineering

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Section: Resultsmentioning

confidence: 99%

Application of Kurtosis to the Interpretation of Current Density Reconstructions

Ziółkowski¹,

Haueisen²

2001

Biomedizinische Technik/Biomedical Engineering

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“…Already the source localization error for the homogeneous measurement was about 4 mm, which is common in such experimental setups. 5,15,27 These errors are attributed to the finite signal-to-noise ratio, the coordinate system transformation error, imaging errors and other experimental inaccuracies. Comparing with HOMOGENEOUS measurement sets, we believe that, this additional error to some extent also to the source localization of measurement ANISOTROPIC POS1 and ANISOTROPIC POS2 (error propagation).…”

Section: Discussionmentioning

confidence: 99%

“…5,15,27 During the measurements the phantom was filled with 0.19 S/m conductivity saline solution to reproduce a physiological conductivity inside the phantom (Fig. 1).…”

Section: Methodsmentioning

confidence: 99%

“…16,20,28,32 The phantom is a realistically shaped torso phantom that had been constructed and used previously. 5,15,27 Bioelectric and biomagnetic measurements were made by using 60 surface electrodes and 195 biomagnetic field sensors 2 cm above the chest, respectively. The heart is modeled by guar gum skeins representing the anisotropy of the heart region.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An Experimental Study on the Effect of the Anisotropic Regions in a Realistically Shaped Torso Phantom

et al. 2008

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Determination of electrically active regions in the human body by observing generated bioelectric and/or biomagnetic signals is known as source reconstruction. In the reconstruction process, it is assumed that the volume conductor consists of isotropic compartments and homogeneous tissue bioelectric parameters but this assumption introduces errors when the tissue of interest is anisotropic. The aim of this study was to investigate changes in the measured signal strengths and the estimated positions and orientations of current dipoles in a realistically shaped torso phantom having a heart region built from single guar gum skeins. Electric data were recorded with 60 electrodes on the front of the chest and 195 sensors measured the magnetic field 2 cm above the chest. The artificial rotating dipoles were located underneath the anisotropic skeins distant from the sensors. It was found that the signal strengths and estimated dipole orientations were influenced by the anisotropy while the estimated dipole positions were not significantly influenced. The signal strength was reduced between 17% and 43% for the different dipole positions when comparing the parallel alignment of dipole orientation and anisotropy direction with the orthogonal alignment. The largest error in the estimation of dipole orientation was 42 degrees. The observed changes in the magnetic fields and electric potentials can be explained by the fact that the anisotropic skeins force the current along its direction. We conclude that taking into account anisotropic structures in the volume conductor might improve signal analysis as well as source strength and orientation estimations for bioelectric and biomagnetic investigations.

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“…The length from the base to the apex of the cardiac phantom was 95 mm, and the width was 65 mm. A realistically shaped physical torso phantom has been applying for increasing the localization accuracy [29], [30]. Here, the physical torso phantom made of fiberglass (Friedrich Schiller University Jena, Germany) in Fig.…”

Section: Phantom Modelmentioning

confidence: 99%

Three-Dimensional Reconstruction of a Cardiac Outline by Magnetocardiography

Kim

Lim

et al. 2015

IEEE Trans. Biomed. Eng.

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A 3-D cardiac visualization is significantly helpful toward clinical applications of magnetocardiography (MCG), but the cardiac reconstruction requires a segmentation process using additional image modalities. This paper proposes a 3-D cardiac outline reconstruction method using only MCG measurement data without further imaging techniques. The cardiac outline was reconstructed by a combination of both spatial filtering and coherence mapping method. The strength of cardiac activities was first estimated by the array-gain constraint minimum-norm spatial filter with recursively updated gram matrix (AGMN-RUG). Then, waveforms were reconstructed at whole source grids, and the maximum source points of an atrium and ventricle were selected as a reference, respectively. Next, the coherence between each maximum source point and whole source points was compared by the coherence mapping method. A reconstructed cardiac outline was validated by comparing with an overlapped volume ratio when the reconstructed volume was identically matched with the original volume. The results obtained by the AGMN-RUG were compared to the results by other spatial filters. The accuracy of numerical simulation and phantom experiment by the AGMN-RUG was superior 10% and 8%, respectively, than the accuracy by the standardized low-resolution electromagnetic tomography. This accuracy demonstrated the efficacy of the proposed 3-D cardiac reconstruction method.

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Source localization in an inhomogeneous physical thorax phantom

Cited by 29 publications

References 25 publications

Application of Kurtosis to the Interpretation of Current Density Reconstructions

Application of Kurtosis to the Interpretation of Current Density Reconstructions

An Experimental Study on the Effect of the Anisotropic Regions in a Realistically Shaped Torso Phantom

Three-Dimensional Reconstruction of a Cardiac Outline by Magnetocardiography

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