Current-induced alternating reversed dual-echo-steady-state for joint estimation of tissue relaxation and electrical properties.
Magn Reson Med
; 78(1): 107-120, 2017 07.
Article
em En
| MEDLINE
| ID: mdl-27489196
ABSTRACT
PURPOSE:
To develop a current-induced, alternating reversed dual-echo-steady-state-based magnetic resonance electrical impedance tomography for joint estimation of tissue relaxation and electrical properties.METHODS:
The proposed method reverses the readout gradient configuration of conventional, in which steady-state-free-precession (SSFP)-ECHO is produced earlier than SSFP-free-induction-decay (FID) while alternating current pulses are applied in between the two SSFPs to secure high sensitivity of SSFP-FID to injection current. Additionally, alternating reversed dual-echo-steady-state signals are modulated by employing variable flip angles over two orthogonal injections of current pulses. Ratiometric signal models are analytically constructed, from which T1 , T2 , and current-induced Bz are jointly estimated by solving a nonlinear inverse problem for conductivity reconstruction. Numerical simulations and experimental studies are performed to investigate the feasibility of the proposed method in estimating relaxation parameters and conductivity.RESULTS:
The proposed method, if compared with conventional magnetic resonance electrical impedance tomography, enables rapid data acquisition and simultaneous estimation of T1 , T2 , and current-induced Bz , yielding a comparable level of signal-to-noise ratio in the parameter estimates while retaining a relative conductivity contrast.CONCLUSION:
We successfully demonstrated the feasibility of the proposed method in jointly estimating tissue relaxation parameters as well as conductivity distributions. It can be a promising, rapid imaging strategy for quantitative conductivity estimation. Magn Reson Med 78107-120, 2017. © 2016 International Society for Magnetic Resonance in Medicine.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pletismografia de Impedância
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Algoritmos
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Processamento de Sinais Assistido por Computador
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Imageamento por Ressonância Magnética
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Interpretação de Imagem Assistida por Computador
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Impedância Elétrica
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Condutometria
Tipo de estudo:
Diagnostic_studies
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Prognostic_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article