BioMedical Engineering and Imaging Institute and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave., 1st Floor, New York, NY, 10029, USA.
Department of Radiology and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 1470 Madison Ave., 1st Floor, New York, NY, 10029, USA.
Sci Rep. 2021 Nov 29;11(1):23034. doi: 10.1038/s41598-021-02533-3.
In recent years, new human magnetic resonance imaging systems operating at static magnetic fields strengths of 7 Tesla or higher have become available, providing better signal sensitivity compared with lower field strengths. However, imaging human-sized objects at such high field strength and associated precession frequencies is limited due to the technical challenges associated with the wavelength effect, which substantially disturb the transmit field uniformity over the human body when conventional coils are used. Here we report a novel passive inductively-coupled radiofrequency resonator array design with a simple structure that works in conjunction with conventional coils and requires only to be tuned to the scanner's operating frequency. We show that inductive-coupling between the resonator array and the coil improves the transmit efficiency and signal sensitivity in the targeted region. The simple structure, flexibility, and cost-efficiency make the proposed array design an attractive approach for altering the transmit field distribution specially at high field systems, where the wavelength is comparable with the tissue size.
近年来，新型磁共振成像系统的静态磁场强度可达 7 特斯拉或更高，与较低场强相比，其信号灵敏度更高。然而，由于与波长效应相关的技术挑战，在如此高的场强和相关进动频率下对人体大小的物体进行成像受到限制，当使用常规线圈时，该波长效应会严重干扰人体的发射场均匀性。在这里，我们报告了一种新颖的无源感应耦合射频谐振器阵列设计，其结构简单，与常规线圈配合使用，只需调谐到扫描仪的工作频率。我们表明，谐振器阵列与线圈之间的感应耦合提高了目标区域的发射效率和信号灵敏度。该设计结构简单、灵活且具有成本效益，使其成为一种有吸引力的方法，可用于改变特别是在高场系统中的发射场分布，因为在这些系统中，波长与组织尺寸相当。
