Non-Invasive in vivo Loss Tangent Imaging: Thermal Sensitivity Estimation at the Larmor Frequency
Investigative Magnetic Resonance Imaging
; : 36-43, 2016.
Article
en En
| WPRIM
| ID: wpr-221982
Biblioteca responsable:
WPRO
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.
Palabras clave
Texto completo:
1
Índice:
WPRIM
Asunto principal:
Imagen por Resonancia Magnética
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Fiebre
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Imanes
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Hipertermia Inducida
Tipo de estudio:
Diagnostic_studies
Idioma:
En
Revista:
Investigative Magnetic Resonance Imaging
Año:
2016
Tipo del documento:
Article