Noise analysis in magnetic resonance electrical impedance tomography at 3 and 11 T field strengths

In magnetic resonance electrical impedance tomography (MREIT), we measure the induced magnetic flux density inside an object subject to an externally injected current. This magnetic flux density is contaminated with noise, which ultimately limits the quality of reconstructed conductivity and current...

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Bibliographic Details
Published inPhysiological measurement Vol. 26; no. 5; pp. 875 - 884
Main Authors Sadleir, Rosalind, Grant, Samuel, Zhang, Sung Uk, Lee, Byung Il, Pyo, Hyun Chan, Oh, Suk Hoon, Park, Chunjae, Woo, Eung Je, Lee, Soo Yeol, Kwon, Ohin, Seo, Jin Keun
Format Journal Article
LanguageEnglish
Published England IOP Publishing 01.10.2005
Subjects
Electric Impedance
Humans
Magnetic Resonance Imaging
Noise
Tomography
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Summary:In magnetic resonance electrical impedance tomography (MREIT), we measure the induced magnetic flux density inside an object subject to an externally injected current. This magnetic flux density is contaminated with noise, which ultimately limits the quality of reconstructed conductivity and current density images. By analysing and experimentally verifying the amount of noise in images gathered from two MREIT systems, we found that a carefully designed MREIT study will be able to reduce noise levels below 0.25 and 0.05 nT at main magnetic field strengths of 3 and 11 T, respectively, at a voxel size of 3 x 3 x 3 mm(3). Further noise level reductions can be achieved by optimizing MREIT pulse sequences and using signal averaging. We suggest two different methods to estimate magnetic flux noise levels, and the results are compared to validate the experimental setup of an MREIT system.
ISSN:0967-3334
1361-6579
DOI:10.1088/0967-3334/26/5/023