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

超高场（3 T和4 T）身体MR成像的灵敏度增加受到缺乏有效身体RF线圈的限制，无法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场和接收场。在本提案中，将证明高效椭圆体积线圈发射器与仅接收表面线圈一起用于在3 T和4 T下进行躯干成像的可行性。该系统将为身体MR成像提供独特的功能。所提出的体积发射线圈将基于椭圆形横截面的可解调传输线谐振器。该线圈的相对较小的几何形状将允许线圈用作可移除的体线圈插入件，其足够有效，可与现成的高频RF放大器（4- 8 kW）一起使用。使用原型系统的初步结果表明所提出的方法的潜力。在第一阶段，我们将完善椭圆体发射器设计，验证PIN二极管失谐电路的使用，以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缺乏显著的共模电流，并证明系统在均匀发射激励和提高图像灵敏度方面的潜在优势，以及在心脏，肝脏，和脊柱。拟议的商业应用：我们计划制作一个可解调椭圆体积线圈插入物，以首次为超过50个且数量不断增长的3 T和4 T人体MR系统提供躯干成像。这些系统主要是大脑研究仪器，但其能力可以通过所提出的设备扩展到以高灵敏度成像身体器官系统。

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.