Concentric dual-loop RF coil for magnetic resonance imaging*
R. Hernándeza, A. Rodríguezb, P. Salgadoc, F.A. Barriosd
a Facultad de Ciencias-Universidad Nacional Autónoma de México, Ciudad Universitaria, México, D.F. 01000, México.
b Departamento de Ingeniería Eléctrica, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, México, D.F, 09340, México, e-mail: arog@xanum.uam.mx
c American British Cowdray Medical Center, Mexico, D. F. 01120, México.
]]> d Instituto de Neurobiología, UNAM-Juriquilla, Querétaro, 76230, México.
Recibido el 12 de julio de 2002.
Aceptado el 11 de diciembre de 2002.
Abstract
A surface coil for MRI consisted of two concentric loops was developed to produce brain images with a commercial MR imager. Prior to build the coil prototype, the magnetic field (B1) generated by the coil was numerically simulated. This field simulation is based on the Biot-Savart law for the circular- and square-shaped loop coils. From these theoretical results, we can appreciate an improvement on the B1 homogeneity. Comparison of experimental SNR for a single-loop and dual concentric figure coils show that the latter has better sensitivity and uniformity. Phantom and brain images were obtained on a 1.5 Tesla clinical imager, and showed a good image quality. These brain images when compared against images obtained with a circular-shaped coil exhibit a better capability of penetration. This receiver coil can generate high quality brain images. This coil design can be used in clinical imagers and is compatible with conventional imaging sequences and protocols.
Keywords: Magnetic resonance imaging; signal-to-noise ratio; surface RF coil; brain imaging.
Resumen
]]> Se desarrollo una antena superficial para ser usada en imagenología por resonancia magnética (IRM) para generar imágenes cerebrales con un sistema RM comercial. Previo a la construcción del prototipo, simulamos el campo magnético generado por la antena. La simulación del campo estuvo basada en la ley de Biot-Savart para los casos de la antenas de una sola espira de forma cuadrada y circular. De estos resultados se puede apreciar una mejora en la homogeneidad del campo. Se compararon los cocientes de señal a ruido (S/R) experimentales de una antena superficial de una sola espira y la antena concéntrica de dos espiras con geometrías distintas. Las gráficas mostraron una mejora en la sensitividad y uniformidad para la antena de figuras concéntricas. Se obtuvieron imágenes de fantoma y cerebrales con un sistema clínico de resonancia magnética de 1.5 Teslas, mostrando una buena calidad de imagen. Este tipo de antenas pueden ser usadas en sistemas clínicos y con secuencias convencionales.Descriptores: Imagenología por resonancia magnética; cociente señal a ruido; antena RF superficial; imagenología cerebral.
PACS: 87.57Ce; 87.61.Ff; 87.61.Lh
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Acknowledgement
We would like to express our gratitude to the American Hospital Cowdray Medical Center for allowing us to carry out all the imaging experiments. We thank General Electric Sistemas Medicos and Schering Mexicana for the support of this research. FAB gratefully acknowledges the National Council of Science and Technology of Mexico (CONACYT) for the research grant: R 31162 A.
]]> References
*. This work was presented in part at the 6th Mexican Symposium on Medical Physics, CINVESTAV-Sur, Mexico, D.F., 2002.
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