Non-Invasive in vivo Loss Tangent Imaging: Thermal Sensitivity Estimation at the Larmor Frequency
Investigative Magnetic Resonance Imaging
;
: 36-43, 2016.
Artigo
em Inglês
| WPRIM
| ID: wpr-221982
ABSTRACT
Visualization of the tissue loss tangent property can provide distinct contrast and offer new information related to tissue electrical properties. A method for non-invasive imaging of the electrical loss tangent of tissue using magnetic resonance imaging (MRI) was demonstrated, and the effect of loss tangent was observed through simulations assuming a hyperthermia procedure. For measurement of tissue loss tangent, radiofrequency field maps (B1+ complex map) were acquired using a double-angle actual flip angle imaging MRI sequence. The conductivity and permittivity were estimated from the complex valued B1+ map using Helmholtz equations. Phantom and ex-vivo experiments were then performed. Electromagnetic simulations of hyperthermia were carried out for observation of temperature elevation with respect to loss tangent. Non-invasive imaging of tissue loss tangent via complex valued B1+ mapping using MRI was successfully conducted. Simulation results indicated that loss tangent is a dominant factor in temperature elevation in the high frequency range during hyperthermia. Knowledge of the tissue loss tangent value can be a useful marker for thermotherapy applications.
Texto completo:
DisponíveL
Índice:
WPRIM (Pacífico Ocidental)
Assunto principal:
Imageamento por Ressonância Magnética
/
Febre
/
Imãs
/
Hipertermia Induzida
Tipo de estudo:
Estudo diagnóstico
Idioma:
Inglês
Revista:
Investigative Magnetic Resonance Imaging
Ano de publicação:
2016
Tipo de documento:
Artigo
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