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 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.
Sadleir
Rosalind
R
Department of Biomedical Engineering, University of Florida, Gainesville, USA.
Grant
Samuel
S
Zhang
Sung Uk
SU
Lee
Byung Il
BI
Pyo
Hyun Chan
HC
Oh
Suk Hoon
SH
Park
Chunjae
C
Woo
Eung Je
EJ
Lee
Soo Yeol
SY
Kwon
Ohin
O
Seo
Jin Keun
JK
D017097:Electric Impedance; D006801:Humans; D008279:Magnetic Resonance Imaging; D009622:Noise; D014054:Tomography