DETUNABLE VOLUME COIL INSERT FOR 3T AND 4T TORSO MRI

超高场(3和4T)人体磁共振成像灵敏度的提高受到缺乏有效的人体射频线圈的限制，以提供均匀体积线圈或仅接收表面线圈成像所需的均匀发射和接收场。在这份提案中，我们将展示一种高效率的椭圆形体积线圈发射机的可行性，该发射机与用于3T和4T躯干成像的仅接收表面线圈一起使用。该系统将为人体磁共振成像提供独特的能力。所提出的体积传输线圈将基于椭圆截面的可调谐传输线谐振器。线圈的相对较小的几何形状将允许线圈用作可拆卸的主体线圈插件，足以有效地与现成的高频射频放大器(4-8kW)一起使用。使用原型系统的初步结果证明了所提出方法的潜力。在第一阶段，我们将改进椭圆体发射机的设计，验证使用PIN二极管失谐电路来消除发射线圈和仅接收线圈之间的相互作用，验证接收线圈电缆上没有显著的共模电流，并展示该系统在均匀发射激励和提高心脏、肝脏和脊柱人体成像图像灵敏度方面的潜在优势。拟议的商业应用：我们计划制造一种可调谐的椭圆体积线圈插入物，首次为50多个和越来越多的3T和4T人体磁共振系统提供躯干成像。这些系统主要是大脑研究仪器，但通过所提出的设备，这些能力可以扩展到高灵敏度的身体器官系统成像。

The increases in sensitivity of ultra-high field (3 and 4T) body MR imaging have been limited by the lack of efficient body RF coils to provide a uniform transmit and receive fields needed for uniform volume coil or receive-only surface coil imaging. In this proposal will demonstrate the feasibility of a high efficiency elliptic volume coil transmitter for use with receive-only surface coils for torso imaging at 3T and 4T. This system will provide unique capabilities for the body MR imaging. The proposed volume transmit coil will be based on a detunable transmission line resonator of elliptic cross section. The relatively small geometry of this coil will allow the coil to be used as a removable body coil insert efficient enough for use with readily available high frequency RF amplifiers (4-8kW). Preliminary results using a prototype system demonstrate the potential of the proposed approach. In Phase I, we will refine the elliptic body transmitter design, validate the use of PIN diode detuning circuitry to eliminate interactions between the transmit coil and a receive-only coil, validate the lack of significant common mode currents on the receive coil cables, and demonstrate the potential advantages of the system in terms of uniform transmit excitation and increased image sensitivity with human imaging in the heart, liver, and spine. PROPOSED COMMERCIAL APPLICATIONS: We plan to make a detunable elliptic volume coil insert to provide torso imaging for the first time to the over 50 and growing number of 3T and 4T human MR systems. These systems are primarily brain research instruments but the capabilities can be expanded to imaging body organ systems with high sensitivity by the proposed device.