A method to localize RF B1 field in high-field magnetic resonance imaging systems.
IEEE Trans Biomed Eng
; 59(12): 3365-71, 2012 Dec.
Article
en En
| MEDLINE
| ID: mdl-22929360
ABSTRACT
In high-field magnetic resonance imaging (MRI) systems, B0 fields of 7 and 9.4 T, the RF field shows greater inhomogeneity compared to clinical MRI systems with B0 fields of 1.5 and 3.0 T. In multichannel RF coils, the magnitude and phase of the input to each coil element can be controlled independently to reduce the nonuniformity of the RF field. The convex optimization technique has been used to obtain the optimum excitation parameters with iterative solutions for homogeneity in a selected region of interest. The pseudoinverse method has also been used to find a solution. The simulation results for 9.4- and 7-T MRI systems are discussed in detail for the head model. Variation of the simulation results in a 9.4-T system with the number of RF coil elements for different positions of the regions of interest in a spherical phantom are also discussed. Experimental results were obtained in a phantom in the 9.4-T system and are compared to the simulation results and the specific absorption rate has been evaluated.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Ingeniería Biomédica
/
Imagen por Resonancia Magnética
Límite:
Humans
Idioma:
En
Revista:
IEEE Trans Biomed Eng
Año:
2012
Tipo del documento:
Article
País de afiliación:
Estados Unidos