RESUMEN
A transceive RF birdcage coil designed for very high field with a novel matching scheme was implemented with the specific geometry chosen for the human knee. This coil design incorporates a hinge for greater patient accessibility. Volunteer human subjects were studied using spin-echo and 3D gradient echo sequences for image acquisition. The higher signal-to-noise and improved tissue contrast obtained from this high-field system, coupled with the optimized coil design, improves visualization of the structural detail in articular cartilage, which is not seen well at conventional field strengths. This has important clinical implications, as newer medical and surgical treatments become available for the treatment of early cartilage degeneration. Magn Reson Med 42:215-221, 1999.
Asunto(s)
Cartílago Articular/anatomía & histología , Cartílago Articular/patología , Articulación de la Rodilla/anatomía & histología , Articulación de la Rodilla/patología , Imagen por Resonancia Magnética/instrumentación , Adulto , Cartílago Articular/lesiones , Diseño de Equipo , Humanos , Aumento de la Imagen , Artropatías/diagnóstico , Traumatismos de la Rodilla/diagnóstico , Persona de Mediana Edad , Fantasmas de ImagenRESUMEN
Functional brain imaging of the human cortex is limited by poor contrast to noise ratio (CNR) and image degradation due to subject motion during the acquisition period. The work described here combines the use of closely coupled phased array receiver coils with a stabilization system to address these needs. Several phased array designs are evaluated and compared with the conventional "birdcage" design. Coil performance is reported in terms of relative SNR and fMRI results. Relative improvements of up to 360% are obtained for the occipital region and 180% in the temporal region. More modest gains of 10-30% were obtained for a "dome"-shaped birdcage volume coil covering the entire cortex.